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Question 1
Correct
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The Meissner’s plexus acts as the main control for gastrointestinal secretion and local blood flow within the gut.The Meissner’s plexus lies in which layer of the gut wall?
Your Answer: Submucosa
Explanation:The Meissner’s plexus (submucosal plexus), an enteric nervous plexus, acts as the main control for gastrointestinal secretion and local blood flow within the gut.It is located in the submucosal layer on the inner surface of the muscularis externa.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 2
Correct
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Pancreatic acinar digestive enzyme secretion is mainly stimulated by which of the following hormones:
Your Answer: Cholecystokinin
Explanation:Exocrine pancreatic secretion is controlled by:Parasympathetic stimulation which enhances secretion of both the enzyme and aqueous componentsSympathetic stimulation which inhibits pancreatic secretionSecretin which stimulates secretion of the alkaline-rich fluid from ductal cellsCholecystokinin which stimulates secretion of the enzyme-rich fluid from acinar cellsSomatostatin which inhibits secretion from both acinar and ductal cellsGastrin which stimulates pancreatic acinar cells to secrete digestive enzymes
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 3
Incorrect
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You proceed to administer lorazepam intravenously to a 21-year-old patient with status epilepticus. Which of the following best describes lorazepam's action?
Your Answer: Inhibits effect of GABA
Correct Answer: Potentiates effect of GABA
Explanation:Lorazepam is a type of benzodiazepine. Benzodiazepines are gamma-aminobutyric acid (GABA) receptor agonists with sedative, hypnotic, anxiolytic, anticonvulsant, and muscle relaxant characteristics that promote inhibitory synaptic transmission across the central nervous system.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 4
Correct
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Carbon dioxide is transported in the blood approximately:
Your Answer: 60% as bicarbonate ions, 30% as carbamino compounds and 10% dissolved in plasma.
Explanation:Carbon dioxide is transported in the blood from tissues to the lungs in three ways as bicarbonate ions (60%), as carbamino compounds with proteins (30%) or simply dissolved in plasma (10%).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 5
Incorrect
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A 32 year old woman presents with episodes of flushing, headaches and palpitations. On examination her blood pressure is significantly elevated. Which of the following is the most likely diagnosis:
Your Answer: Cushing's syndrome
Correct Answer: Pheochromocytoma
Explanation:Phaeochromocytomas are catecholamine-secreting tumours which occur in about 0.1% of patients with hypertension. In about 90% of cases they arise from the adrenal medulla. The remaining 10%, which arise from extra-adrenal chromaffin tissue, are termed paragangliomas. Common presenting symptoms include one or more of headache, sweating, pallor and palpitations. Less commonly, patients describe anxiety, panic attacks and pyrexia. Hypertension, whether sustained or episodic, is present in at least 90% of patients. Left untreated phaeochromocytoma can occasionally lead to hypertensive crisis, encephalopathy, hyperglycaemia, pulmonary oedema, cardiac arrhythmias, or even death.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 6
Correct
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Ipratropium bromide should be used with caution in patients with which of the following conditions:
Your Answer: Prostatic hyperplasia
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma)
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 7
Incorrect
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You are instructed by a senior to administer Mannitol to an RTA patient with increased intracranial pressure. Mannitol is a low molecular weight compound that freely filters at the glomerulus and is not reabsorbed.Out of the following, which is a contraindication to the use of mannitol?
Your Answer: Jaundice
Correct Answer: Severe pulmonary oedema
Explanation:Mannitol is the most widely used osmotic diuretic that is most commonly used to reduce cerebral oedema and intracranial pressure. It is recommended to use mannitol for the reduction of CSF pressure/cerebral oedema in a dose of 0.25-2 g/kg as an intravenous infusion over 30-60 minutes. This can be repeated 1-2 times after 4-8 hours if needed.Mannitol has several contraindications and some of them are listed below:1. Anuria due to renal disease2. Acute intracranial bleeding (except during craniotomy)3. Severe cardiac failure4. Severe dehydration5. Severe pulmonary oedema or congestion6. Known hypersensitivity to mannitol
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 8
Incorrect
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A 39-year-old man with a long history of depression presents after intentionally overdoing his heart medication. Verapamil immediate-release 240 mg is the tablet he takes for this condition, he says. He took the pills about 30 minutes ago, but his wife discovered him right away and rushed him to the emergency room.Which of the following is a verapamil toxicity?
Your Answer: Increased afterload
Correct Answer: Negative inotropy
Explanation:Overdosing on calcium-channel blockers should always be taken seriously and regarded as potentially fatal. Verapamil and diltiazem are the two most lethal calcium-channel blockers in overdose. These work by binding the alpha-1 subunit of L-type calcium channels, preventing calcium from entering the cell. In cardiac myocytes, vascular smooth muscle cells, and islet beta-cells, these channels play an important role.The following summarises the toxicity of calcium-channel blockers:Cardiac effectsVascular smooth muscle tone affectsMetabolic effectsExcessive negative inotropy: myocardial depressionNegative chronotropy: sinus bradycardiaNegative dromotropy: atrioventricular node blockadeDecreased afterloadSystemic hypotensionCoronary vasodilationHypoinsulinaemiaCalcium channel blocker-induced insulin resistance
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 9
Correct
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Foetal haemoglobin (HbF) comprises about how much of the total haemoglobin in adults:
Your Answer: 0.5 - 0.8%
Explanation:Foetal haemoglobin (HbF) makes up about 0.5 – 0.8 % of total adult haemoglobin and consists of two α and two gamma (γ) globin chains.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 10
Incorrect
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An analytical cohort study is done to compare the relationship between omega 3 intake and occurrence of myocardial infarction (MI) among males aged over 65 years. The following are the data from the study:No. of subjects taking placebo: 100 menNo. of subjects taking placebo who suffered an MI: 15 menNo. of subjects taking omega 3: 100 menNo. of subjects taking omega 3 who suffered an MI: 5 menCompute for the relative risk of the study.
Your Answer: 0.15
Correct Answer: 0.33
Explanation:Relative risk (RR) is a ratio of the probability of an event occurring in the exposed group versus the probability of the event occurring in the non-exposed group.RR can be computed as the absolute risk of events in the treatment group (ART), divided by the absolute risk of events in the control group (ARC).RR = ART/ARCRR = (5/100) / (15/100)RR = 0.33
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This question is part of the following fields:
- Evidence Based Medicine
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Question 11
Correct
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Regarding ACE inhibitors, which of the following statements is CORRECT:
Your Answer: Angiotensin-II receptor blockers are a useful alternative in patients who cannot tolerate ACE-inhibitors due a persistent cough.
Explanation:ACE inhibitors should be used with caution in patients of Afro-Caribbean descent who may respond less well; calcium channel blockers are first line for hypertension in these patients. ACE inhibitors have a role in the management of diabetic nephropathy. ACE inhibitors are contraindicated in pregnant women. ACE inhibitors inhibit the breakdown of bradykinin; this is the cause of the persistent dry cough. Blocking ACE also diminishes the breakdown of the potent vasodilator bradykinin which is the cause of the persistent dry cough. Angiotensin-II receptor blockers do not have this effect, therefore they are useful alternative for patients who have to discontinue an ACE inhibitor because of persistent cough.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 12
Correct
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A 24 year old male sustained an insect bite and presents with a red hot arm and acute cellulitis has been diagnosed. The predominant white cells in this type of acute inflammation are:
Your Answer: Neutrophils
Explanation:Neutrophil polymorphs are the predominant type of white cells in an acute reaction. They pass between endothelial cell junctions to invade damaged tissue so that the effects of injury can be combated. Extravasation occurs with the movement of leukocytes out of the vessel lumen, and is achieved in five phases which are margination, ‘rolling’, adhesion, transmigration and chemotaxis.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 13
Incorrect
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A patient presents with increased breathlessness and worsening of his chronic cough and. He has a chronic lung disorder and is on long-term oxygen therapy (LTOT).Which of these is an indication for LTOT?
Your Answer: A non-smoker with COPD and a PaO 2 of 7.5 kPa when stable
Correct Answer: A non-smoker with COPD and a PaO 2 of 7.5 kPa when stable with secondary polycythaemia
Explanation:Long-term administration of oxygen, usually at least 15 hours daily, improves survival in COPD patients who have severe hypoxaemia. Long-term oxygen therapy should be considered in:A non-smoker with COPD and a PaO2<7.3 kPa when stableA non-smoker with COPD and PaO27.3–8 kPa when stable and with secondary polycythaemia, peripheral oedema, or evidence of pulmonary hypertensionSevere chronic asthma with PaO2<7.3 kPa or persistent disabling breathlessnessA patient with Interstitial lung disease with PaO28 kPa with disabling dyspnoeaA patient with cystic fibrosis when PaO2<7.3 kPa or if PaO27.3–8 kPa in the presence of secondary polycythaemia, nocturnal hypoxaemia, pulmonary hypertension, or peripheral oedemaPulmonary hypertension, without parenchymal lung involvement when PaO2<8 kPaNeuromuscular or skeletal disorders, after specialist assessmentObstructive sleep apnoea despite continuous positive airways pressure therapy, after specialist assessmentPulmonary malignancy or other terminal disease with disabling dyspnoeaHeart failure with daytime PaO2<7.3 kPa when breathing air or with nocturnal hypoxaemia
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 14
Incorrect
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The movement of molecules across the cell membrane relies greatly on active transport.Which of the following statements about active transport is correct?
Your Answer: The proton pump is an example of secondary active transport
Correct Answer: Active transport occurs in glucose absorption from the gut
Explanation:The movement of a material against a concentration gradient, i.e. from a low to a high concentration, is known as active transport. Primary active transport is defined as active transport that involves the use of chemical energy, such as adenosine triphosphate (ATP). Secondary active transport occurs when an electrochemical gradient is used.The sodium-potassium pump, calcium ATPase pump, and proton pump are all key active transport systems that use ATP. An electrochemical gradient is used by the sodium-calcium co-transporter, which is an example of secondary active transport.The sodium-dependent hexose transporter SGLUT-1 transports glucose and galactose into enterocytes. Secondary active transport is exemplified here.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 15
Correct
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A 52-year old male comes to the out-patient department for a groin mass that protrudes when standing. The patient notes that it is reducible when lying down. On physical examination, there is presence of a cough impulse. The initial assessment is hernia. Further investigation reveals that the mass lies lateral to the epigastric vessels.Among the types of hernia, which is the most likely diagnosis of the case above?
Your Answer: Indirect inguinal hernia
Explanation:Inguinal hernias can present with an array of different symptoms. Most patients present with a bulge in the groin area, or pain in the groin. Some will describe the pain or bulge that gets worse with physical activity or coughing. Symptoms may include a burning or pinching sensation in the groin. These sensations can radiate into the scrotum or down the leg. It is important to perform a thorough physical and history to rule out other causes of groin pain. At times an inguinal hernia can present with severe pain or obstructive symptoms caused by incarceration or strangulation of the hernia sac contents. A proper physical exam is essential in the diagnosis of an inguinal hernia. Physical examination is the best way to diagnose a hernia. The exam is best performed with the patient standing. Visual inspection of the inguinal area is conducted first to rule out obvious bulges or asymmetry in groin or scrotum. Next, the examiner palpates over the groin and scrotum to detect the presence of a hernia. The palpation of the inguinal canal is completed last. The examiner palpates through the scrotum and towards the external inguinal ring. The patient is then instructed to cough or perform a Valsalva manoeuvre. If a hernia is present, the examiner will be able to palpate a bulge that moves in and out as the patient increases intra abdominal pressure through coughing or Valsalva.Groin hernias are categorized into 2 main categories: inguinal and femoral.Inguinal hernias are further subdivided into direct and indirect. An indirect hernia occurs when abdominal contents protrude through the internal inguinal ring and into the inguinal canal. This occurs lateral to the inferior epigastric vessels. The hernia contents may extend into the scrotum, and can be reduced superiorly then superolaterally. A direct inguinal hernia is protrusion of abdominal contents through the transversalis fascia within Hesselbach’s triangle. The borders of Hesselbach’s triangle are the inferior epigastric vessels superolaterally, the rectus sheath medially, and inguinal ligament inferiorly.A femoral hernia is a protrusion into the femoral ring. The borders of the femoral ring are the femoral vein laterally, Cooper’s ligament posteriorly, the iliopubic tract/inguinal ligament anteriorly and lacunar ligament medially.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 16
Correct
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A patient is referred to the Medicine Department for complaints of unilateral hearing loss, tinnitus and facial numbness. Upon further investigation, an acoustic neuroma is given as the final diagnosis.Which of the following nerves is least likely to be affected in acoustic neuroma?
Your Answer: Trochlear nerve
Explanation:Acoustic neuroma is also called vestibular schwannoma (VS), acoustic neuroma, vestibular neuroma or acoustic neurofibroma. These are tumours that evolve from the Schwann cell sheath and can be either intracranial or extra-axial. They usually occur adjacent to the cochlear and vestibular nerves and most often arise from the inferior division of the latter. Anatomically, acoustic neuroma tends to occupy the cerebellopontine angle. About 5-10% of cerebellopontine angle (CPA) tumours are meningiomas and may occur elsewhere in the brain. Bilateral acoustic neuromas tend to be exclusively found in individuals with type 2 neurofibromatosis.The following nerves may be affected due to nerve compression:Facial nerve: usually minimal with late presentation except for very large tumours. Depending on the degree of engagement of the nerve, the symptoms may include twitching, increased lacrimation and facial weakness.Trigeminal Nerve: paraesthesia in the trigeminal distribution, tingling of the tongue, impairment of the corneal reflex, and less commonly pain which may mimic typical trigeminal neuralgia.Glossopharyngeal and Vagus nerves: palatal paresis, hoarseness of voice and dysphagia
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 17
Correct
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Most of the lymph from vessels that drain the breast is collected in which of the following lymph nodes?
Your Answer: Axillary nodes
Explanation:Lymph is the fluid that flows through the lymphatic system. Axillary lymph nodes are near the breasts. They are often the first location to which breast cancer spreads if it moves beyond the breast tissue. They receive approximately 75% of lymph drainage from the breast via lymphatic vessels, laterally and superiorly. The lymph usually first drains to the anterior axillary nodes, and from here, through the central axillary, apical, and supraclavicular nodes in sequence.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 18
Correct
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A 69-year-old man with a history of chronic anaemia is transfused. He takes bisoprolol and furosemide for his cardiac failure, and his most recent BNP was 123 pmol/l. He developed shortness of breath and his pre-existing peripheral oedema became worse 5 hours after transfusion was commenced. His BP rises to 170/105 mmHg and a repeat measurement of his BNP is 192 pmol/l.What is the most likely transfusion reaction to have occurred?
Your Answer: TACO
Explanation:Transfusion-associated circulatory overload (TACO) presents as acute or worsening respiratory distress within 6 hours of transfusion of a large volume of blood. It is common in patients with diminished cardiac reserve or chronic anaemia. Elderly patients, infants and severely anaemic patients are particularly susceptible. Typical clinical features of TACO include: Acute respiratory distress, Tachycardia, Hypertension, Acute/worsening pulmonary oedema on chest X-ray. The BNP is usually raised to at least 1.5 times the pre-transfusion baseline.Febrile transfusion reaction presents with a 1 degree rise in temperature from baseline during transfusion. Patient may have chills and malaise. It is the most common transfusion reaction (1 in 8 transfusions) and is usually caused by cytokines released from leukocytes in transfused red cell or platelet components. TRALI (Transfusion Related Acute Lung Injury) is a clinical syndrome with abrupt onset of non-cardiogenic pulmonary oedema within 6 hours of transfusion not explained by another risk factor. Associated with the presence of antibodies in the donor blood to recipient leukocyte antigens. patients present with dyspnoea, hypertension, hypotension, acute leukopenia. Graft versus host disease(GVHD) is an immune mediated condition that arises from a complex interaction between donor and recipients adaptive immunity. It presents as dermatitis, hepatitis and enteritis developing within 100 days after stem cell or bone marrow transplant.Acute haemolytic reaction aka immediate haemolytic transfusion reaction presents with fever, chills, pain at transfusion site, nausea, vomiting, dark urine and feeling of ‘impending doom’. Often, it occurs due to ABO incompatibility.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 19
Incorrect
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Regarding platelets, which of the following statements is CORRECT:
Your Answer: Normally about 60% of the total body pool of platelets is stored in the spleen.
Correct Answer: Platelets are produced in the bone marrow by fragmentation of the cytoplasm of megakaryocytes.
Explanation:Platelets are produced in the bone marrow by fragmentation of the cytoplasm of megakaryocytes, derived from the common myeloid progenitor cell. The time interval from differentiation of the human stem cell to the production of platelets averages 10 days. Thrombopoietin is the major regulator of platelet formation and 95% of this is produced by the liver. The normal platelet count is approximately 150 – 450 x 109/L and the normal platelet lifespan is 10 days. Under normal circumstances, about one-third of the marrow output of platelets may be trapped at any one time in the normal spleen.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 20
Incorrect
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Red cell protein expression is induced by which of the following pathogens:
Your Answer: Epstein-Barr virus
Correct Answer: Plasmodium falciparum
Explanation:Plasmodium falciparum induces the expression of red cell protein, making cerebral malaria more severe. Bacteria may invade a host passively through micro traumata or macro traumata in the skin or mucosa. On the other hand, bacteria that invadethrough intact mucosa first, adhere to this anatomical barrier, then activelybreach it.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 21
Incorrect
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All of the following statements are considered true regarding likelihood ratios, except:
Your Answer: They provide a way to estimate the pre-test probabilities of having a condition
Correct Answer: A likelihood ratio less than 1 indicates that the result is associated with the presence of the disease
Explanation:The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.The LR is used to assess how good a diagnostic test is and to help in selecting an appropriate diagnostic tests or sequence of tests. They have advantages over sensitivity and specificity because they are less likely to change with the prevalence of the disorder, they can be calculated for several levels of the symptom/sign or test, they can be used to combine the results of multiple diagnostic test and they can be used to calculate post-test probability for a target disorder.A LR greater than 1 produces a post-test probability which is higher than the pre-test probability. An LR less than 1 produces a post-test probability which is lower than the pre-test probability. When the pre-test probability lies between 30 and 70 per cent, test results with a very high LR (say, above 10) rule in disease. An LR below 1 produces a post-test probability les than the pre-test probability. A very low LR (say, below 0.1) virtually rules out the chance that the patient has the disease.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 22
Correct
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You've been summoned to a young man in the resus area who has an SVT. You decide to use adenosine after trying several vagal manoeuvres without success.The use of adenosine is not contraindicated in which of the following situations?
Your Answer: Concurrent use of a beta-blocker
Explanation:The use of a beta-blocker at the same time increases the risk of myocardial depression, but it is not a contraindication.The use of adenosine is contraindicated in the following situations:AsthmaCOPD (chronic obstructive pulmonary disease)Decompensated heart failure Long QT syndromeAV block in the second or third degreeSinusitis is a condition in which the sinuses become (unless pacemaker fitted)Hypotension that is severe
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 23
Incorrect
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The most important nerve for plantar flexion of the foot at the ankle joint is:
Your Answer: Superficial fibular nerve
Correct Answer: Tibial nerve
Explanation:Muscles of the posterior compartment of the leg, innervated by the tibial nerve, perform plantar flexion of the foot at the ankle joint. The fibularis longus (innervated by the superficial fibular nerve) assists in plantar flexion but is not the most important.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 24
Correct
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A 27-year-old athlete presents with buttock pain after tearing his gluteus maximus muscle.In which of the following nerves is the gluteus maximus muscle innervated by?
Your Answer: Inferior gluteal nerve
Explanation:The gluteal muscles are a group of muscles that make up the buttock area. These muscles include: gluteus maximus, gluteus medius. and gluteus minimus.The gluteus maximus is the most superficial as well as largest of the three muscles and makes up most of the shape and form of the buttock and hip area. It is a thick, fleshy muscle with a quadrangular shape. It is a large muscle and plays a prominent role in the maintenance of keeping the upper body erect.The innervation of the gluteus maximus muscle is from the inferior gluteal nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 25
Correct
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What is the pathophysiology of a phaeochromocytoma:
Your Answer: Catecholamine-secreting tumour
Explanation:Phaeochromocytomas are catecholamine-secreting tumours which occur in about 0.1% of patients with hypertension. In about 90% of cases they arise from the adrenal medulla. The remaining 10%, which arise from extra-adrenal chromaffin tissue, are termed paragangliomas. Common presenting symptoms include one or more of headache, sweating, pallor and palpitations. Less commonly, patients describe anxiety, panic attacks and pyrexia. Hypertension, whether sustained or episodic, is present in at least 90% of patients. Left untreated phaeochromocytoma can occasionally lead to hypertensive crisis, encephalopathy, hyperglycaemia, pulmonary oedema, cardiac arrhythmias, or even death.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 26
Incorrect
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A 39-year-old woman's son with meningococcal meningitis was recently admitted to the Paediatric Intensive Care Unit. She is currently 22 weeks pregnant and is concerned about the possibility of her also contracting the disease as she cared closely for her son during his admission. Which antibiotic would be the MOST appropriate choice for chemoprophylaxis in this case?
Your Answer: Penicillin V
Correct Answer: Ciprofloxacin
Explanation:Ciprofloxacin is recommended for use as meningococcal chemoprophylaxis in all age groups and in pregnancy, and is the most appropriate for this patient.However, rifampicin is the drug of choice for meningococcal chemoprophylaxis because it is licensed for chemoprophylaxis, but multiple doses are necessary and it is not readily available in community pharmacies. It also interacts with oral contraceptives.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 27
Incorrect
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C5 - C9 deficiency increases susceptibility to infection with which of the following:
Your Answer: Intracellular bacteria
Correct Answer: Neisseria spp.
Explanation:If the complement sequence is completed, an active phospholipase (the membrane attack complex, MAC) is produced, which punches holes in the cell membrane and causes cell lysis. Because the MAC appears to be the sole means to destroy the Neisseria family of bacteria, C5 – C9 deficiency increases susceptibility to Neisseria infections.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 28
Incorrect
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Which of the following occurs at the transverse thoracic plane:
Your Answer: Thoracic duct crosses from left to right hand side
Correct Answer: Bifurcation of the trachea
Explanation:A way to help remember the structures transected by the transverse thoracic plane is CLAPTRAP:C: cardiac plexusL: ligamentum arteriosumA: aortic arch (inner concavity)P: pulmonary trunkT: tracheal bifurcation (carina)R: right-to-left movement of the thoracic duct (posterior to the oesophagus)A: azygos vein drains into superior vena cavaP: pre-vertebral fascia and pre-tracheal fascia end
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 29
Correct
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Which of the following is NOT a contraindication to the use of diazepam:
Your Answer: Acute alcohol withdrawal
Explanation:Benzodiazepines are used to treat symptoms in patients with acute alcohol withdrawal syndrome. Benzodiazepines are contraindicated in: Respiratory depressionMarked neuromuscular respiratory weakness, such as unstable myasthenia gravisObstructive sleep apnoea syndrome (symptoms may be aggravated)Severe hepatic impairment (the elimination half-life of diazepam may be prolonged; increased risk of coma)Phobic or obsessional states, chronic psychosis or hyperkinesis (paradoxical reactions may occur).
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 30
Correct
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A 50-year-old man presents with signs and symptoms of an anaphylactic reaction. His GP had recently given him a new medication.Which one of these is the most likely medication responsible for the drug-induced anaphylactic reaction?
Your Answer: Penicillin
Explanation:The most common cause of drug-induced anaphylaxis is penicillin.The second commonest cause are NSAIDs. Other drugs associated with anaphylaxis are ACE inhibitors and aspirin.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 31
Correct
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A 70-year-old man presents with right-sided hemiplegia and loss of joint position sense, vibratory sense, and discriminatory touch. Upon further physical examination, it was observed that her tongue deviates to the left-hand side. An MRI and CT scan was ordered and results showed that he was suffering a left-sided stroke. Branches of which of the following arteries are most likely implicated in the case?
Your Answer: Anterior spinal artery
Explanation:Medial medullary syndrome is a form of stroke that affects the medial medulla of the brain. It is caused by a lesion in the medial part of the medulla, which is due to an infraction of vertebral arteries and/or paramedian branches of the anterior spinal artery.It is characterized by contralateral paralysis of the upper and lower limb of the body, a contralateral decrease in proprioception, vibration, and/or fine touch sensation, paresthesias or less commonly dysesthesias in the contralateral trunk and lower limb, and loss of position and vibration sense with proprioceptive dysfunction. Ipsilateral deviation of the tongue due to ipsilateral hypoglossal nerve damage can also be seen.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 32
Correct
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Regarding box and whisker plots, which of the following statements is true?
Your Answer: 25% of the values lie below the lower quartile
Explanation:A box and whisker plot is defined as a graphical method of displaying variation in a set of data. In most cases, a histogram analysis provides a sufficient display, but a box and whisker plot can provide additional detail while allowing multiple sets of data to be displayed in the same graph.The procedure to develop a box and whisker plot comes from the five statistics below:(1) Minimum value: The smallest value in the data set(2) Second quartile: The value below which the lower 25% of the data are contained(3) Median value: The middle number in a range of numbers(4) Third quartile: The value above which the upper 25% of the data are contained(5) Maximum value: The largest value in the data set
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This question is part of the following fields:
- Evidence Based Medicine
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Question 33
Correct
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The transport of oxygen from maternal to fetal circulation is made possible by fetal haemoglobin. Which of the statements about fetal haemoglobin (HbF) is also correct?
Your Answer: The oxygen dissociation curve for foetal haemoglobin is shifted to the left of that of adult haemoglobin
Explanation:Fetal haemoglobin is the most common type of haemoglobin found in the foetus during pregnancy. It transports oxygen from the maternal circulation to the fetal circulation. It can easily bind to oxygen from the maternal circulation because it has a high affinity for oxygen. From 10 to 12 weeks of pregnancy to the first six months after birth, the erythroid precursor cells produce fetal haemoglobin. In comparison to adult haemoglobin, fetal haemoglobin has two alpha and two gamma subunits, whereas adult haemoglobin has two alpha and two beta subunits in its major form. And, unlike adult haemoglobin, the oxygen dissociation curve of fetal haemoglobin is left-shifted. Myoglobin is an oxygen storage molecule with a very high affinity for oxygen. Only when the partial pressure of oxygen is exceeded does it release oxygen.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 34
Incorrect
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A 68-year-old man with multiple myeloma presents with complaints of abdominal pain and malaise. A series of blood tests is done and his calcium level is 2.96 mmol/l.What effect will this blood test result have on gastric secretions?
Your Answer: Inhibit the release of histamine
Correct Answer: Stimulate the release of gastrin
Explanation:Hypercalcaemia stimulates the release of gastrin from the G-cells in the pyloric antrum of the stomach, the duodenum and the pancreas.Gastrin is also released in response to:Stomach distensionVagal stimulationThe presence of amino acids.Gastrin release is inhibited by the presence of acid and somatostatin.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 35
Correct
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Which of the following diseases is caused by a build-up of lymphoblasts in the bone marrow?
Your Answer: Acute lymphoblastic leukaemia
Explanation:Acute lymphoblastic leukaemia (ALL) is a clonal (malignant) bone marrow disorder in which early lymphoid precursors multiply and replace the marrow’s normal hematopoietic cells. ALL is most common between the ages of 3 and 7, with 75 percent of cases occurring before the age of 6.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 36
Incorrect
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Question 37
Correct
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What is the direct mechanism of action of digoxin as a positive inotrope:
Your Answer: Inhibition of Na+/K+ ATPase pump
Explanation:Digoxin directly inhibits membrane Na+/K+ ATPase, which is responsible for Na+/K+ exchange across the myocyte cell membrane. This increases intracellular Na+ and produces a secondary increase in intracellular Ca2+ that increases the force of myocardial contraction. The increase in intracellular Ca2+ occurs because the decreased Na+ gradient across the membrane reduces the extrusion of Ca2+ by the Na+/Ca2+ exchanger that normally occurs during diastole. Digoxin and K+ ions compete for the receptor on the outside of the muscle cell membrane, and so the effects of digoxin may be dangerously increased in hypokalaemia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 38
Incorrect
-
A 2nd-year medical student is solving an exam paper with questions about the immune system. She comes across a question regarding innate immunity. Innate immunity is the immunity naturally present within the body from birth. Which ONE of the following is not a part of this type of immunity?
Your Answer: The cough reflex
Correct Answer: Antibody production
Explanation:Innate immunity, also called non-specific immunity, refers to the components of the immune system naturally present in the body at birth. The components of innate immunity include: 1) Natural Killer Cells 2) Neutrophils 3) Macrophages 4) Mast Cells 5) Dendritic Cells 6) Basophils. Acquired or adaptive immunity is acquired in response to infection or vaccination. Although the response takes longer to develop, it is also a more long-lasting form of immunity. The components of this system include: 1) T lymphocytes 2) B lymphocytes 3) Antibodies
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 39
Incorrect
-
A 24-year-old patient is suspected to have a possible acute hepatitis B infection and is currently under investigation.Which of the following markers is considered the earliest indicator of acute infection in acute Hepatitis B?
Your Answer: IgM antibody to hepatitis B core antigen
Correct Answer: Hepatitis B surface Ag
Explanation:HBsAg is the serological hallmark of HBV infection. After an acute exposure to HBV, HBsAg appears in serum within 1 to 10 weeks. Persistence of this marker for more than 6 months implies chronic HBV infection.Anti-HBs is known as a neutralizing antibody, and confers long-term immunity. In patients with acquired immunity through vaccination, anti-HBs is the only serological marker detected in serum.HBcAg is an intracellular presence in infected hepatocyte, thus it is not identified in the serum. During acute infection, anti-HBc IgM and IgG emerges 1–2 weeks after the presence of HBsAg along with raised serum aminotransferase and symptoms. After 6 months of acute infection, anti-HBc IgM wears off. Anti-HBc IgG continues to detect in both patients with resolved HBV infection and chronic hepatitis B.Hepatitis D virus, also known as the delta hepatitis virus, is a defective ssRNA virus that requires HBV for replication. The infection can occur in one of two clinical forms, co-infection or superinfection. In a co-infection, the patient is simultaneously infected with HBV and HDV. In a superinfection, an HDV infection develops in a patient with a chronic HBV infection.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 40
Correct
-
A 29 year old patient with known inflammatory bowel disease presents to ED with surgical complications following his recent ileocaecal resection. Removal of the terminal ileum may result in the malabsorption of which of the following:
Your Answer: Vitamin B12
Explanation:On ingestion, vitamin B12 is bound to R protein found in saliva and gastric secretions, which protects it from digestion in the stomach. Intrinsic factor is secreted by gastric parietal cells. Receptors for the IF-B12 complex are present in the membrane of epithelial cells of the terminal ileum, which bind the complex and allow uptake of vitamin B12 across the apical membrane by endocytosis. Vitamin B12 is then transported across the basal membrane into the portal blood where it is bound to transcobalamin II and processed by the liver. In pernicious anaemia, there are autoantibodies against gastric parietal cells and intrinsic factor, resulting in vitamin B12 deficiency anaemia.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 41
Correct
-
Angiotensin II is part of the RAAS system. One of its effects is the constriction of efferent arterioles. Which of the following best describes the effect of angiotensin II- mediated constriction of efferent arterioles?
Your Answer: Decreased renal plasma flow, increased filtration fraction, increased GFR
Explanation:The Renin-Angiotensin-Aldosterone System (RAAS) is a hormone system composed of renin, angiotensin, and aldosterone. Those hormones are essential for the regulation of blood pressure and fluid balance. Cases of hypotension, sympathetic stimulation, or hyponatremia can activate the Renin-angiotensin-aldosterone system (RAAS). The following process will then increase the blood volume and blood pressure as a response. When renin is released it will convert the circulating angiotensinogen to angiotensin I. The ACE or angiotensin-converting enzyme will then catalyst its conversion to angiotensin II, which is a potent vasoconstrictor. Angiotensin II can constrict the vascular smooth muscles and the efferent arteriole of the glomerulus. The efferent arteriole is a blood vessel that delivers blood away from the capillaries of the kidney. The angiotensin II-mediated constriction of efferent arterioles increases GFR, reduces renal blood flow and peritubular capillary hydrostatic pressure, and increases peritubular colloid osmotic pressure, as a response to its action of increasing the filtration fraction.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 42
Correct
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Which of the following immunoglobulins is most important for mast cell degranulation:
Your Answer: IgE
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 43
Correct
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An analytical cohort study aimed to determine a relationship between intake of dietary calcium and incidence of hip fractures among post-menopausal women. The following are the data obtained from the study:No. of post-menopausal women who took Calcium: 500No. of post-menopausal women who took Calcium and suffered a hip fracture: 10No. of post-menopausal women who took placebo: 500No. of post-menopausal women who took placebo and suffered a hip fracture: 25Compute for the absolute risk in the placebo group.
Your Answer: 0.05
Explanation:The absolute risk (AR) is the probability or chance of an event. It is computed as the number of events in treated or control groups, divided by the number of people in that group.AR = 25/500 = 0.05
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This question is part of the following fields:
- Evidence Based Medicine
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Question 44
Correct
-
Renal potassium excretion is promoted by all but which one of the following:
Your Answer: Increased intracellular magnesium
Explanation:Aldosterone: A rise in [K+] in the extracellular fluid of the adrenal cortex directly stimulates aldosterone release. Aldosterone promotes the synthesis of Na+/K+ATPases and the insertion of more Na+/K+ATPases into the basolateral membrane, and also stimulates apical sodium and potassium channel activity, overall acting to increase sodium reabsorption and potassium secretion.pH changes: Potassium secretion is reduced in acute acidosis and increased in acute alkalosis. A higher pH increases the apical K+channel activity and the basolateral Na+/K+ATPase activity – both changes that promote K+secretion.Flow rates: Increased flow rates in the collecting duct reduce K+concentration in the lumen and therefore enhance K+secretion. Increased flow also activates BK potassium channels, and ENaC channels which promote potassium secretion and sodium reabsorption respectively.Sodium delivery: Decreased Na+delivery to the collecting ducts results in less Na+reabsorption and hence a reduced gradient for K+secretion.Magnesium: Intracellular magnesium can bind and block K+channels inhibiting K+secretion into the tubules. Therefore magnesium deficiency reduces this inhibitory effect and so allows more potassium to be secreted into tubules and can cause hypokalaemia.
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This question is part of the following fields:
- Physiology
- Renal
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Question 45
Incorrect
-
One of the following pathogens is a conditional pathogen:
Your Answer: Mycobacterium tuberculosis
Correct Answer: Neisseria meningitidis
Explanation:Obligate pathogens include Mycobacterium TB, HIV, Treponema pallidum, and Neisseria gonorrhoeae. Neisseria meningitidis, on the other hand, is a conditional pathogen.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 46
Incorrect
-
A 7-year-old girl is admitted to the hospital with a persistently high temperature. To help her reduce her fever, you decide to give her paracetamol and ibuprofen.What are the effects of paracetamol and ibuprofen on fever?
Your Answer: Resetting of the central thermostatic control
Correct Answer: Reduction in prostaglandin synthesis
Explanation:Interleukin-1, which is released by leukocytes and acts on the thermoregulatory centre of the hypothalamus, causes fever. Because prostaglandins mediate this process, antipyretics such as NSAIDs, paracetamol, and aspirin reduce prostaglandin levels by inhibiting cyclooxygenase enzymes. Malignant disease secretes interleukins, which cause the B-symptoms seen in lymphoma, for example. Bacterial toxins can also cause interleukins to be produced.Pyrexia of unknown origin (PUO) is defined as a fever of greater than 38.3 degrees Celsius that lasts for more than 2-3 weeks with no clear diagnosis despite extensive investigation.Investigation necessitates a thorough understanding of the conditions that can cause febrile illness, which may be missed during an initial investigation, as well as a thorough history, examination, and investigation centred on that list.Pyrexia of unknown origin has a wide differential diagnosis, which includes:InfectionBacterialPyogenic abscessTuberculosisInfective endocarditisBrucellosisLyme diseaseViralHIV Epstein Barr VirusCytomegalovirusParasiteToxoplasmosisMalignancy LeukaemiaLymphomaRenal cell carcinomaHepatocellular carcinomaVasculitides Still’s diseaseGranulomatosis with polyangiitis (formerly Wegener’s)Systemic lupus erythematosusGiant cell arteritisRheumatoid arthritisPolymyalgia rheumaticaMiscellaneous Drug induced fevers Familial Mediterranean feverThyrotoxicosisInflammatory bowel diseaseSarcoidosisFactitious fever Exaggerated normal circadian fluctuationThe patient might need to be admitted to the hospital for observation and further investigation. Because infection is still a possibility, blood cultures should be repeated on a regular basis, and inflammatory markers should be closely monitored. CT, PET, and MRI imaging have largely replaced diagnostic laparotomy as a diagnostic tool.
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This question is part of the following fields:
- Pathology
- Pathology Of Infections
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Question 47
Incorrect
-
Oedema can occur as a result of any of the following WITH THE EXCEPTION OF:
Your Answer: Decreased plasma oncotic pressure
Correct Answer: Increased interstitial hydrostatic pressure
Explanation:Oedema is defined as a palpable swelling produced by the expansion of the interstitial fluid volume. A variety of clinical conditions are associated with the development of oedema, including heart failure, cirrhosis, and nephrotic syndrome. The development of oedema requires an alteration in capillary dynamics in a direction that favours an increase in net filtration and also inadequate removal of the additional filtered fluid by lymphatic drainage. Oedema may form in response to an elevation in capillary hydraulic pressure (which increases the delta hydraulic pressure) or increased capillary permeability, or it can be due to disruption of the endothelial glycocalyx, decreased interstitial compliance, a lower plasma oncotic pressure (which reduces the delta oncotic pressure), or a combination of these changes. Oedema can also be induced by lymphatic obstruction since the fluid that is normally filtered is not returned to the systemic circulation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 48
Incorrect
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A 42-year-old woman with a history of hyposplenism arrives at the Emergency Department sick and feverish. A complete set of bloods, including a peripheral blood film, is organised.On a hyposplenic blood film, which of the following features is LEAST likely to be seen?
Your Answer: Target cells
Correct Answer: Teardrop cells
Explanation:The collection of abnormalities found in these patients is referred to as a hyposplenic film.The following features can be seen on hyposplenic blood films:Howell-Jolly bodiesHeinz’s bodiesTarget cellsRBCs with nuclei on occasionLymphocytosisMacrocytosisAcanthocytesTeardrop cells, also known as dacrocytes, are named for their teardrop-shaped shape. Dacrocytosis is a condition in which a large number of these cells are present. Myelofibrosis and beta thalassemia major both have dacrocytes, but hyposplenism does not.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 49
Correct
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A mother has serious concerns about vaccinating her child. She has read about many contraindications and risks in the papers and would like to discuss them with you.One of these is a valid contraindication to vaccination.
Your Answer: None of the other options
Explanation:The options listed in this question are not true contraindications to vaccination. Therefore, the correct answer is ‘none of the other options’.The contraindications to vaccination are:Confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.A confirmed anaphylactic reaction to another component in the vaccine.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 50
Incorrect
-
Regarding fibrinolytics, which of the following statements is INCORRECT:
Your Answer: Tenecteplase has a longer half-life than alteplase allowing for bolus administration.
Correct Answer: Fibrinolytic drugs act as thrombolytics by directly degrading the fibrin mesh and so breaking up thrombi.
Explanation:Fibrinolytic drugs act as thrombolytics by activating plasminogen to form plasmin, which degrades fibrin and so breaks up thrombi.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 51
Incorrect
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Fibrinoid necrosis is typically seen in which of the following:
Your Answer: Myocardial infarction
Correct Answer: Malignant hypertension
Explanation:Fibrinoid necrosis occurs in malignant hypertension where increased arterial pressure results in necrosis of smooth muscle wall. Eosinophilic and fibrinous deposits are seen.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 52
Incorrect
-
A patient presents with a rash for dermatological examination. A large area of purplish discolouration of the skin that measures 2 cm in diameter and does not blanch when pressure is applied is seen .What is the best description of this rash that you have found on examination?
Your Answer: Purpura
Correct Answer: Ecchymoses
Explanation:Ecchymosis are discolouration of the skin or mucous membranes caused by extravasation of blood. They are usually red or purple in colour and measure greater than 1 cm in diameter and do not blanch on applying pressure. A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin. Petechiae are discolouration of the skin measuring less than 3 mm in diameterPurpura are discolouration of the skin measuring between 0.3 cm and 1 cm in diameter.Erythema is redness of the skin or mucous membranes caused by hyperaemia of superficial capillaries caused by skin injury, infection or inflammation. Erythema blanches when pressure is applied whereas ecchymosis, purpura and petechiae do not.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 53
Correct
-
Which of the following infections is vancomycin most likely prescribed for?
Your Answer: Clostridium difficile colitis
Explanation:125 mg PO q6hr for 10 days is indicated for treatment of Clostridium difficile (C. difficile)-associated diarrhoea
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 54
Incorrect
-
The following are all examples of type III hypersensitivity EXCEPT for:
Your Answer: Extrinsic allergic alveolitis
Correct Answer: Goodpasture's syndrome
Explanation:Examples of type III reactions include:Extrinsic allergic alveolitisSystemic lupus erythematosus (SLE)Post-streptococcal glomerulonephritisReactive arthritisRheumatoid arthritis
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 55
Correct
-
Regarding iron handling, which of the following statements is CORRECT:
Your Answer: Iron is taken across the enterocyte apical membrane by the divalent metal transporter (DMT1).
Explanation:Dietary iron may be in the form of haem or non-haem iron. Haem iron is degraded after absorption through the cell surface to release Fe2+. Most non-haem iron is in the form Fe3+, which is reduced at the luminal surface to the more soluble Fe2+, facilitated by hydrochloric acid in gastric secretions (and enhanced by ascorbic acid). Fe2+is taken across the enterocyte apical membrane by the divalent metal transporter (DMT1). In the enterocyte, Fe2+is then either stored in enterocyte epithelial cells as ferritin, or released into portal plasma via the molecule ferroportin at the basolateral membrane.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 56
Incorrect
-
Approximately what percentage of filtered bicarbonate is reabsorbed in the proximal tubule:
Your Answer: 60 - 70%
Correct Answer: 0.8
Explanation:Bicarbonate is freely filtered at the glomerulus. Less than 0.1% of filtered bicarbonate is normally excreted in the urine (if plasma [HCO3-] increases, maximum tubular transport is exceeded and some HCO3-is excreted in urine). About 80% of bicarbonate is reabsorbed in the proximal tubule. For each H+secreted into the lumen, one Na+and one HCO3-are reabsorbed into the plasma. H+is recycled so there is little net secretion of H+at this stage. A further 10 – 15% of HCO3-is similarly reabsorbed in the thick ascending limb of the loop of Henle. In the early distal tubule, H+secretion is predominantly by Na+/H+exchange but more distally, the Na+gradient is insufficient so secretion is via H+ATPase and H+/K+ATPase in intercalated cells, which contain plentiful carbonic acid. As secreted H+is derived from CO2, new HCO3-is formed and returns to the blood.H+secretion is proportional to intracellular [H+] which itself is related to extracellular pH. A fall in blood pH will therefore stimulate renal H+secretion. In the proximal tubule secretion of H+serves to reclaim bicarbonate from glomerular filtrate so it is not lost, but in the distal nephron, secretion leads to net acid excretion and generation of new bicarbonate.
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This question is part of the following fields:
- Physiology
- Renal
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Question 57
Correct
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A 50-year-old woman has an anaphylactic reaction following accidental ingestion peanuts at a restaurant. She is a known hypertensive on atenolol 50 mg daily and BP is well controlled. She is also on amlodipine 5 mg daily. Two doses of IM adrenaline has been given without improvement.Which medication may prove helpful in this patient?
Your Answer: IM Glucagon
Explanation:Resistant to the effects of adrenaline in anaphylaxis is seen in patients taking beta-blockers.Glucagon can be used to overcome the effects of the beta-blockade if initial doses of adrenaline are unsuccessful in patients taking beta-blockers.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 58
Correct
-
Which of the following nerves innervates the gastrocnemius muscle?
Your Answer: Tibial nerve
Explanation:The gastrocnemius is innervated by the anterior rami of S1 and S2 spinal nerves, carried by the tibial nerve into the posterior compartment of the leg.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 59
Correct
-
During bedside rounds, an 82-year old female in the Medicine Ward complains of pain and tingling of all fingers of the right hand. The attending physician is considering carpal tunnel syndrome.Which of the following is expected to undergo atrophy in carpal tunnel syndrome?
Your Answer: The thenar eminence
Explanation:Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression of the median nerve as it travels through the wrist’s carpal tunnel. It is the most common nerve entrapment neuropathy, accounting for 90% of all neuropathies. Early symptoms of carpal tunnel syndrome include pain, numbness, and paraesthesia’s. These symptoms typically present, with some variability, in the thumb, index finger, middle finger, and the radial half (thumb side) of the ring finger. Pain also can radiate up the affected arm. With further progression, hand weakness, decreased fine motor coordination, clumsiness, and thenar atrophy can occur.The muscles innervated by the median nerve can be remembered using the mnemonic ‘LOAF’:L– lateral two lumbricalsO– Opponens pollicisA– Abductor pollicisF– Flexor pollicis brevisIn the early presentation of the disease, symptoms most often present at night when lying down and are relieved during the day. With further progression of the disease, symptoms will also be present during the day, especially with certain repetitive activities, such as when drawing, typing, or playing video games. In more advanced disease, symptoms can be constant.Typical occupations of patients with carpal tunnel syndrome include those who use computers for extended periods of time, those who use equipment that has vibration such as construction workers, and any other occupation requiring frequent, repetitive movement.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 60
Incorrect
-
What is the interquartile range for these numbers: 11, 4, 6, 8, 3, 10, 8, 10, 4, 12, 31?
Your Answer: 5
Correct Answer: 7
Explanation:We obtain 3, 4, 4, 6, 8, 8, 10, 11, 12, and 31, and sample size (n) = 11 when we order the data. [(n+1)/2] = median 6th value = (11+1)/2 = [(n+1)/4] represents the bottom (first) quartile. (3rd value = 4th value = (11 + 1)/4 3[(n+1)/4] for the top (third) quartile 3[(11 + 1)/4] = 9th value = 11th value = 11th value = 11th value = 11th value = 11th value = 11th value = 11th value = 11th The difference between the upper and lower quartiles is the interquartile range, which is equal to 11 minus 4 = 7.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 61
Correct
-
Which of the following ions is more abundant in extracellular fluid than in intracellular fluid:
Your Answer: Cl -
Explanation:Protein and phosphate are the primary intracellular anions, while chloride (Cl-) and bicarbonate are the predominant extracellular anions (HCO3-).
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 62
Correct
-
Which of the following side effects would you least associated with ciprofloxacin:
Your Answer: Folate deficiency
Explanation:Common side effects include diarrhoea, dizziness, headache, nausea and vomiting.Other adverse effects include: Tendon damage (including rupture), Seizures (in patients with and without epilepsy), QT-interval prolongation, Photosensitivity and Antibiotic-associated colitis
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 63
Correct
-
A 75-year-old man with rheumatoid arthritis had gained weight, developed resistant hypertension, muscle weakness, and ankle oedema. This patient is most likely suffering from what condition?
Your Answer: Cushing's syndrome
Explanation:Overuse of cortisol medication, as seen in the treatment of patients with chronic asthma or rheumatoid arthritis, can cause Cushing’s syndrome. Weight gain, thin arms and legs, a round face, increased fat around the base of the neck, a fatty hump between the shoulders, easy bruising, wide purple stretch marks primarily on the abdomen, breasts, hips, and under the arms, weak muscles, hirsutism, hypertension, erectile dysfunction, osteoporosis, frontal alopecia, acne, depression, poor wound healing, and polycythaemia are all clinical features of Cushing’s syndrome.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 64
Correct
-
Eosinophils comprise what percentage of circulating white cells:
Your Answer: 1 - 3%
Explanation:Eosinophils comprise 1 – 3% of circulating white cells. Eosinophils are similar to neutrophils, except that the cytoplasmic granules are coarser and more deeply red staining, and there are rarely more than three nuclear lobes. They are less motile, but longer lived. They enter inflammatory exudates and have a special role in allergic responses, defence against parasites and removal of fibrin formed during inflammation. Thus they play a role in local immunity and tissue repair.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 65
Correct
-
An elderly man with chronic heart and lung disease develops Legionnaires' disease. Which of the following clinical features is NOT typical of Legionnaires' disease:
Your Answer: Haemoptysis
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 66
Correct
-
Which of the following is the correct sequential order of the phases of healing:
Your Answer: Haemostasis, inflammation, proliferation, remodelling
Explanation:Acute wound healing has four main stages: haemostasis, inflammation, proliferation and remodelling.
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This question is part of the following fields:
- Pathology
- Wound Healing
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Question 67
Incorrect
-
Regarding skeletal muscle, which of the following best describes the Z-line:
Your Answer: A line dividing the thick and the thin myofilaments
Correct Answer: A line dividing muscle fibres into sarcomeres
Explanation:Each muscle fibre is divided at regular intervals along its length into sarcomeres separated by Z-lines. The sarcomere is the functional unit of the muscle.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 68
Correct
-
Parathyroid hormone is released by which of the following:
Your Answer: Chief cells of the parathyroid gland
Explanation:Parathyroid hormone (PTH) is a peptide hormone synthesised by the chief cells of the parathyroid glands, located immediately behind the thyroid gland. PTH is primarily released in response to decreasing plasma [Ca2+] concentration. PTH acts to increase plasma calcium levels and decrease plasma phosphate levels.Parathyroid hormone (PTH) acts to increase calcium reabsorption in the distal tubule of the nephron (by activating Ca2+entry channels in the apical membrane and the Ca2+ATPase pump in the basolateral membrane) and increase phosphate excretion by inhibiting reabsorption in the proximal tubule of the nephron.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 69
Incorrect
-
Which of the following describes the site of a Meckel's diverticulum:
Your Answer: Second part of duodenum
Correct Answer: Ileum
Explanation:Meckel’s lies on the antimesenteric surface of the middle-to-distal ileum, approximately 2 feet proximal to the ileocaecal junction. It appears as a blind-ended tubular outpouching of bowel, about 2 inches long, occurring in about 2% of the population, and may contain two types of ectopic tissue (gastric and pancreatic). The rich blood supply to the diverticulum is provided by the superior mesenteric artery.Proximal to the major duodenal papilla the duodenum is supplied by the gastroduodenal artery (branch of the coeliac trunk) and distal to the major duodenal papilla it is supplied by the inferior pancreaticoduodenal artery (branch of superior mesenteric artery). The arterial supply to the jejunoileum is from the superior mesenteric artery.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 70
Correct
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A 50-year-old man from Russia presents with a history of cough with blood-stained sputum, fever, night sweats, and weight loss. Suspecting tuberculosis, you begin investigations.All the following statements regarding tuberculosis (TB) are true EXCEPT?
Your Answer: Corticosteroid use is not a risk factor for developing TB
Explanation:Immunosuppressants like corticosteroids may be an important risk factor for developing tuberculosis. All of the other statements are true.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 71
Correct
-
C3 deficiency leads to particular susceptibility of infection with which of the following:
Your Answer: Encapsulated bacteria
Explanation:Macrophages and neutrophils have C3b receptors and they phagocytose C3b-coated cells. C3 deficiency thus leads to increased susceptibility of infection with encapsulated organisms (e.g. S. pneumoniae, H. influenzae).The early stages of the complement cascade leading to coating of the cells with C3b can occur by two different pathways:The classical pathway usually activated by IgG or IgM coating of cellsThe alternative pathway which is more rapid and activated by IgA, endotoxin and other factors
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 72
Correct
-
Regarding postural hypotension, which of the following statements is INCORRECT:
Your Answer: Postural hypotension usually causes a reflex bradycardia.
Explanation:On standing from a prone position, gravity causes blood to pool in veins in the legs. Central venous pressure (CVP) falls, causing a fall in stroke volume and cardiac output (due to Starling’s law) and thus a fall in blood pressure. Normally this fall in BP is rapidly corrected by the baroreceptor reflex which causes venoconstriction (partially restoring CVP), and an increase in heart rate and contractility, so restoring cardiac output and blood pressure. Impaired autonomic nervous activity in the elderly accounts for the greater likelihood of postural hypotension. Any symptoms of dizziness, blurred vision or syncope is due to a transient fall in cerebral perfusion that occurs before cardiac output and mean arterial pressure (MAP) can be corrected.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 73
Incorrect
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You've been requested to give a discussion to a group of medical students about cardiovascular physiology. One of them inquires about cardiac output and asks if you can explain it.Which of the following statements is correct?
Your Answer: An average resting cardiac output in a man is 4 L/min
Correct Answer: An average resting cardiac output in a woman is 5 L/min
Explanation:The terminology cardiac output refers to the amount of blood pumped by the heart in one minute. Women’s rates are around 5 L/min, whereas men’s rates are somewhat higher, around 5.5 L/min.Cardiac output (CO) is calculated by multiplying stroke volume (SV) by heart rate (HR):CO = HR x SVAs a result, both stroke volume and heart rate are exactly proportional to cardiac output. There will be an increase in cardiac output if the stroke volume or heart rate increases, and a reduction in cardiac output if the stroke volume or heart rate lowers.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 74
Correct
-
The most common complication of paracetamol overdose is:
Your Answer: Hepatic failure
Explanation:The maximum daily dose of paracetamol in an adult is 4 grams. Doses greater than this can lead to hepatotoxicity and, less frequently, acute kidney injury. Early symptoms of paracetamol toxicity include nausea, vomiting, and abdominal pain, and usually settle within 24 hours. Symptoms of liver damage include right subcostal pain and tenderness, and this peaks 3 to 4 days after paracetamol ingestion. Other signs of hepatic toxicity include encephalopathy, bleeding, hypoglycaemia, and cerebral oedema.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 75
Correct
-
The sensory innervation of the oropharynx is provided by which of the following nerves:
Your Answer: Glossopharyngeal nerve
Explanation:Each subdivision of the pharynx has a different sensory innervation:the nasopharynx is innervated by the maxillary nervethe oropharynx is innervated by the glossopharyngeal nervethe laryngopharynx is innervated by the vagus nerve.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 76
Correct
-
A patient suffered from a chest injury while working out in the gym. As a consequence of his injury, his pectoralis minor muscle was damaged.Which of the following statements regarding the pectoralis minor muscle is considered correct?
Your Answer: It stabilises the scapula
Explanation:The pectoralis minor, in comparison to the pectoralis major, is much thinner and triangular in shape and resides below the major. It originates from the margins of the third to fifth ribs adjacent to the costochondral junction. The fibres consequently pass upward and laterally to insert into the medial border and superior surface of the coracoid process. It is crucial in the stabilization of the scapula by pulling it downward and anteriorly against the thoracic wall.Arterial supply to the pectoralis minor also derives from the pectoral branch of the thoracoacromial trunk. Nerve supply of the pectoralis minor is a function of the lateral pectoral nerve and the medial pectoral nerve.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 77
Correct
-
A newborn baby girl is delivered vaginally to a 19-year old female, however with complications due to cephalopelvic disproportion. Upon examination by the attending paediatrician, there is a notable 'claw hand' deformity of the left, and sensory loss of the ulnar aspect of the left distal upper extremity.What is the most probable diagnosis of the case above?
Your Answer: Klumpke’s palsy
Explanation:Klumpke palsy, named after Augusta Dejerine-Klumpke, is a neuropathy involving the lower brachial plexus. In contrast, the more common Erb–Duchenne palsy involves the more cephalic portion of the brachial plexus C5 to C6. The brachial plexus is a bundle of individual nerves that exit between the anterior and middle scalene muscles in the anterior lateral and basal portion of the neck. Although the most common anatomical presentation of the brachial plexus is between the anterior and middle scalene, there are variations, with the most common being penetration of the anterior scalene. The main mechanism of injury to the lower brachial plexus is hyper-abduction traction, and depending on the intensity, it will lead to signs and symptoms consistent with a neurological insult.The most common aetiology resulting in Klumpke palsy is a hyper-abduction trauma to the arm that has enough intensity to traction the lower brachial plexus. Trauma during birth can cause brachial plexus injuries, but again hyper-abduction and traction forces to the upper extremity are usually present.The history presented by the patient usually depicts a long axis hyper-abduction traction injury with high amplitude and velocity. The typical patient presentation is a decrease of sensation along the medial aspect of the distal upper extremity along the C8 and T1 dermatome. The patient might also present myotome findings that can range from decreasing muscular strength to muscular atrophy and positional deformity. For example, if the neurological damage has led to muscular atrophy and tightening, the patient may present with a claw hand. This deformity presents a finger and wrist flexion. The patient may also describe the severe pain that starts at the neck and travels down the medial portion of the arm. One other sign of a lower brachial plexus injury is Horner syndrome; because of its approximation to the T1 nerve root, it may damage the cephalic sympathetic chain. If this happens, the patient will develop ipsilateral ptosis, anhidrosis, and miosis.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 78
Incorrect
-
Approximately what proportion of lymphocytes are B-cells:
Your Answer: 0.35
Correct Answer: 0.2
Explanation:B-cells (20% of lymphocytes) mature in the bone marrow and circulate in the peripheral blood until they undergo recognition of antigen. B-cell immunoglobulin molecules synthesised in the cell are exported and bound to the surface membrane to become the B-cell receptor (BCR) which can recognise and bind to a specific antigen (either free or presented by APCs). The BCR is also important for antigen internalisation, processing and presentation to T helper cells. Most antibody responses require help from antigen-specific T helper cells (although some antigens such as polysaccharide can lead to T-cell independent B-cell antibody production). When the B-cell is activated, the receptor itself is secreted as free soluble immunoglobulin and the B-cell matures into a memory B-cell or a plasma cell (a B-cell in its high-rate immunoglobulin secreting state). Plasma cells are non-motile and are found predominantly in the bone marrow or spleen. Most plasma cells are short-lived (1 – 2 weeks) but some may survive much longer. A proportion of B-cells persist as memory cells, whose increased number and rapid response underlies the augmented secondary response of the adaptive immune system.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 79
Incorrect
-
Identify the type of graph described below:A graph wherein the frequency distribution is represented by adjoining vertical bars and cases are stacked in adjoining columns. It can be used for continuous quantitative data, such as to analyse outbreak data to show an epidemic curve.
Your Answer: Forest plot
Correct Answer: Histogram
Explanation:A histogram is used to demonstrate the distribution of continuous quantitative data. It is a very familiar graphical display device for representing the distribution of a single batch of data. The range of the data is divided into class intervals or bins, and the number of values falling into each interval is counted. The histogram then consists of a series of rectangles whose widths are defined by the class limits implied by the binwidths, and whose heights depend on the number of values in each bin. Histograms quickly reveal such attributes of the data distribution as location, spread, and symmetry. If the data are multimodal (i.e., more than one “hump” in the distribution of the data), this is quickly evident as well.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 80
Correct
-
A 55-year-old woman was complaining of headaches. On examination, the patient is found to have weakness on the left side of her body and her eyes are deviated towards the right hand side. These are signs of damage to which of the following areas?
Your Answer: Frontal lobe
Explanation:Some potential symptoms of frontal lobe damage can include loss of movement, either partial or complete, on the opposite side of the body. In the patient’s case, it is a result of motor cortex damage on the right side since her left side of the body is affected. The conjugate eye deviation symptom towards the side of the lesion is a result of damage to the frontal eye field.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 81
Incorrect
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A 70-year-old man presents with right-sided hemiplegia and loss of joint position sense, vibratory sense, and discriminatory touch. Upon further physical examination, it was observed that her tongue deviates to the left-hand side. An MRI and CT scan was ordered and results showed that he was suffering a left-sided stroke. Which of the following is considered the best diagnosis for the case presented above?
Your Answer: Lateral medullary syndrome
Correct Answer: Medial medullary syndrome
Explanation:Medial medullary syndrome is a form of stroke that affects the medial medulla of the brain. It is caused by a lesion in the medial part of the medulla, which is due to an infraction of vertebral arteries and/or paramedian branches of the anterior spinal artery.It is characterized by contralateral paralysis of the upper and lower limb of the body, a contralateral decrease in proprioception, vibration, and/or fine touch sensation, paresthesias or less commonly dysesthesias in the contralateral trunk and lower limb, and loss of position and vibration sense with proprioceptive dysfunction. Ipsilateral deviation of the tongue due to ipsilateral hypoglossal nerve damage can also be seen.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 82
Incorrect
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An 18-year-old student presents with a 1-week history of sore throat, low grade fever, and malaise. Upon history taking, she noted that she had a fine rash over her body a week ago that quickly fades. Further examination and observation was done and the presence of mild splenomegaly was noted. Her test shows positive for heterophile antibody test, suspecting a diagnosis of infectious mononucleosis.Which of the following characteristics is mostly associated with the diagnosis of infectious mononucleosis?
Your Answer: Pruritic maculopapular rash
Correct Answer: Atypical lymphocytes
Explanation:Epstein-Barr virus causes infectious mononucleosis which is a clinical entity characterized by sore throat, cervical lymph node enlargement, fatigue and fever. It is accompanied by atypical large peripheral blood lymphocytes. These atypical lymphocytes, also known as Downey cells, are actually activated CD8 T lymphocytes, most of which are responding to EBV-infected cells.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 83
Correct
-
Which of the following microbes binds strongly to CD4 antigen:
Your Answer: HIV
Explanation:HIV mainly infects CD4+ T helper cells. Viral replication results in progressive T-cell depletion and impaired cell-mediated immunity with subsequent secondary opportunistic infections and increased risk of malignancy. B-cell function is also reduced as a result of lack of T-cell stimulation.HIV is not a notifiable disease.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 84
Correct
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A 45-year-old businessman returns from a trip to West Africa with headaches and intermittent fevers. Thick and thin films are sent to the lab and a diagnosis is made of malaria. The patient is started on treatment but his condition deteriorates and he develops jaundice, renal failure and haemoglobinuria.Which of the following is the MOST likely causative organism? Select ONE answer only.
Your Answer: Plasmodium falciparum
Explanation:Malaria is an infectious disease transmitted by female of theAnophelesgenus of mosquito. It is a parasitic infection caused by the genusPlasmodium. Five species are recognized as causing disease in humans;Plasmodium falciparum,Plasmodium ovale,Plasmodium vivax,Plasmodium malariaeandPlasmodium knowlesi.The classic symptom of malaria is the malarial paroxysm, a cyclical occurrence of a cold phase, where the patient experiences intense chills, a hot stage, where the patient feels extremely hot and finally a sweating stage, where the fever declines and the patient sweats profusely. On examination the patient may show signs of anaemia, jaundice and have hepatosplenomegaly without evidence of lymphadenopathy.Plasmodium falciparum is the most serious form and is responsible for most deaths. Severe or complicated malaria is suggested by the presence of impaired consciousness, seizures, hypoglycaemia, anaemia, renal impairment, respiratory distress and spontaneous bleeding.Plasmodium falciparum is the most likely type in this case in view of the presentation.Haemoglobinuria and renal failure following treatment is suggestive of blackwater fever, which is caused byPlasmodium falciparum. An autoimmune reaction between the parasite and quinine causes haemolysis, haemoglobinuria, jaundice and renal failure. This can be fatal.The benign malarias: P.vivax, P. malariae and P.ovale are usually treated with chloroquine. A course of primaquine is also required in P.vivax and P.ovale infection. Artesunate is the drug treatment of choice for Plasmodium falciparum malaria. Quinine can still be used where artesunate is not available. Often combination therapy with drugs such as doxycycline or fansidar is also required.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 85
Correct
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Which of the following is NOT a function of the commensal intestinal bacterial flora:
Your Answer: Breakdown of haem into bilirubin
Explanation:Commensal intestinal bacterial flora have a role in:Keeping pathogenic bacteria at bay by competing for space and nutrientConverting conjugated bilirubin to urobilinogen (some of which is reabsorbed and excreted in urine) and stercobilinogen which is excreted in the faecesThe synthesis of vitamins K, B12, thiamine and riboflavinThe breakdown of primary bile acids to secondary bile acidsThe breakdown of cholesterol, some food additives and drugs
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 86
Incorrect
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A 32-old woman comes for a follow-up visit after being discharged on medications for her newly diagnosed epilepsy. She now complains of a tremor in her arm when she holds a tray in her hand. You examine the patient and notice she has developed postural tremors. Which of the following medications for epilepsy is most likely responsible for this tremor?
Your Answer: Phenytoin
Correct Answer: Sodium valproate
Explanation:A postural tumour is observed when a person maintains a position against gravity, such as holding the arms outstretched. (The patient holding her tray against gravity) Sodium valproate is the most commonly prescribed medication for epilepsy. It is commonly associated with tremors as valproate-induced tremors occur in around 6-45% of patients. The tremors are commonly postural, but a resting tremor may also occur.Approximately 25% of patients taking sodium valproate are found to develop a tremor within 3-12 months of initiating therapy.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 87
Correct
-
Compliance is decreased by all but which one of the following:
Your Answer: Aging
Explanation:Factors increasing compliance:Old ageEmphysemaFactors decreasing compliance:Pulmonary fibrosisPulmonary oedemaAtelectasisExtremes of lung volumes (at higher lung volumes the compliance of the lung becomes less as the lung becomes stiffer)
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 88
Incorrect
-
What is the average healing time for a femoral shaft fracture under normal circumstances? Choose ONE answer.
Your Answer: 6-8 weeks
Correct Answer: 12 weeks
Explanation:The process of fracture healing occurs naturally after traumatic bone disruption and begins with haemorrhage, then progresses through Inflammatory, reparative, and remodelling stagesAverage healing times of common fractures are:Femoral shaft: 12 weeksTibia: 10 weeksPhalanges: 3 weeksMetacarpals: 4-6 weeksDistal radius: 4-6 weeksHumerus: 6-8 weeks
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 89
Correct
-
Regarding the cardiac cycle, which of the following statements is INCORRECT:
Your Answer: The second heart sound occurs in late diastole caused by closure of the atrioventricular valves.
Explanation:Diastole is usually twice the length of systole at rest, but decreases with increased heart rate. During systole, contraction of the ventricles compresses the coronary arteries and suppresses blood flow. This is particularly evident in the left ventricle, where during systole the ventricular pressure is the same as or greater than that in the arteries and as a result more than 85% of left ventricular perfusion occurs during diastole. This becomes a problem if the heart rate is increased as the diastolic interval is shorter and can result in ischaemia. The second heart sound, caused by closure of the semilunar valves, marks the end of systole.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 90
Correct
-
What is the most common application of Nitrates?
Your Answer: Angina
Explanation:In patients with exertional stable angina, nitrates improve exercise tolerance, time to onset of angina, and ST-segment depression during exercise testing. In combination with beta-blockers or calcium channel blockers, nitrates produce greater anti-anginal and anti-ischemic effects.While they act as vasodilators, coronary vasodilators, and modest arteriolar dilators, the primary anti ischemic effect of nitrates is to decrease myocardial oxygen demand by producing systemic vasodilation more than coronary vasodilation. This systemic vasodilation reduces left ventricular systolic wall stress.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 91
Incorrect
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A 4-year-old child has been convulsing for 20 minutes. She has received two doses of lorazepam. She takes phenytoin for maintenance therapy, and you draw up a phenobarbitone infusion.What dose of phenobarbitone is advised in the treatment of the convulsing child that reaches that stage of the APLS algorithm? Select ONE answer only.
Your Answer: 10 mg/kg over 30-60 minutes
Correct Answer: 20 mg/kg over 30-60 minutes
Explanation:If a convulsing child reaches step 3 of the APLS algorithm, then a phenytoin infusion should be set up at 20 mg/kg over 20 minutes. If they are already taken phenytoin as maintenance therapy, then a phenobarbitone infusion should be set up at 20 mg/kg over 30-60 minutes.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 92
Correct
-
After collapsing in his nursing home, a 70-year-old man is brought into the ER. He has diabetes mellitus and is on medication for it. An RBS of 2.0 mmol/L (3.9-5.5 mmol/L) is recorded in the ER. Out of the following, which medication for diabetes mellitus is LEAST likely responsible for his hypoglycaemic episode?
Your Answer: Metformin
Explanation:Metformin is a biguanide used as the first-line to treat type 2 diabetes mellitus. It has a good reputation as it has an extremely low risk of causing hypoglycaemia compared to the other agents for diabetes. It does not affect the insulin secreted by the pancreas or increase insulin levels. Toxicity with metformin can, however, cause lactic acidosis with associated hypoglycaemia.
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This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
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Question 93
Correct
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Where: Capillary hydrostatic pressure is (P c) Hydrostatic pressure in the interstices is (P I )Plasma oncotic pressure is (π p) Interstitial oncotic pressure is (π i)Which of the following formulas best represents fluid flow at the capillary bed?
Your Answer: Volume / min = (P c - P i ) - (π p - π i )
Explanation:Starling’s equation for fluid filtration describes fluid flow at the capillary bed.Filtration forces (capillary hydrostatic pressure and interstitial oncotic pressure) stimulate fluid movement out of the capillary, while resorption forces promote fluid movement into the capillary (interstitial hydrostatic pressure and plasma oncotic pressure). Although the forces fluctuate along the length of the capillary bed, overall filtration is achieved.At the capillary bed, there is fluid movement.The reflection coefficient (σ), the surface area accessible (S), and the hydraulic conductance of the wall (Lp) are frequently used to account for the endothelium’s semi-permeability, yielding:Volume / min = LpS [(Pc- Pi) – σ(πp– πi)]Volume /min = (Pc-Pi) – (πp–πi) describes the fluid circulation at the capillaries.Where:Pc= capillary hydrostatic pressurePi= interstitial hydrostatic pressureπp= plasma oncotic pressureπi= interstitial oncotic pressure
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 94
Correct
-
A 12-year old boy is taken to the emergency room after accidentally falling off the monkey bars. Witnesses of the accident reported that, when the patient fell, he hit his right hand on a bar and a loud thump was heard. On examination, the hand is oedematous, tender and erythematous. On ultrasound, a rupture of the flexor carpi ulnaris is noted.Which of the following statements is true regarding the flexor carpi ulnaris?
Your Answer: It acts to adduct the hand at the wrist joint
Explanation:Flexor carpi ulnaris is a fusiform muscle located in the anterior compartment of the forearm. It belongs to the superficial flexors of the forearm, along with pronator teres, palmaris longus, flexor digitorum superficialis and flexor carpi radialis. Flexor carpi ulnaris is the most medial of the superficial flexors.Innervation of the flexor carpi ulnaris muscle is from the brachial plexus via the ulnar nerve (C7-T1).Flexor carpi ulnaris receives its arterial blood supply via three different routes. Proximally, a branch of the posterior ulnar recurrent artery supplies the muscle as it passes between the humeral and ulnar heads. Branches of the ulnar artery supply the middle and distal parts of the muscle, with an accessory supply also present distally via the inferior ulnar collateral artery.Due to its position and direction in the forearm, flexor carpi ulnaris can move the hand sideways as well as flexing it. Contracting with flexor carpi radialis and palmaris longus, flexor carpi ulnaris produces flexion of the hand at the wrist joint. However, when it contracts alongside the extensor carpi ulnaris muscle in the posterior compartment, their counteracting forces produce adduction of the hand at the wrist, otherwise known as ulnar deviation or ulnar flexion
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 95
Incorrect
-
Which of the following is most true of the sinoatrial node:
Your Answer: It is a region of specialised nerve cells that can initiate an impulse.
Correct Answer: Frequency of depolarisation is increased by sympathetic stimulation.
Explanation:Cardiac myocyte contraction is not dependent on an external nerve supply but instead the heart generates its own rhythm, demonstrating inherent rhythmicity. The heartbeat is initiated by spontaneous depolarisation of the sinoatrial node (SAN), a region of specialised myocytes in the right atrium close to the coronary sinus, at a rate of 100-110 beats/min. This intrinsic rhythm is primarily influenced by autonomic nerves, with vagal influences being dominant over sympathetic influences at rest. This vagal tone reduces the resting heart rate down to 60-80 beats/min. To increase heart rate, the autonomic nervous system increases sympathetic outflow to the SAN, with concurrent inhibition of vagal tone. These changes mean the pacemaker potential more rapidly reaches the threshold for action potential generation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 96
Correct
-
A 21-year-old student presents to the minors area of your Emergency Department with a laceration on his external nose that occurred during sparring in a kickboxing class. The area is bleeding profusely and will require suturing. Pressure is being applied. The laceration extends through some of the nasal muscles.Motor innervation of the nasal muscles of facial expression is provided by which of the following ? Select ONE answer only.
Your Answer: Facial nerve
Explanation:The facial nerve (the labyrinthine segment) is the seventh cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue.Motor innervation of the nasal muscles of facial expression is provided by the facial nerve (CN VII).
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 97
Correct
-
An analytical cohort study is done to compare the relationship between omega 3 intake and occurrence of myocardial infarction (MI) among males aged over 65 years. The following are the data from the study:No. of subjects taking placebo: 100 menNo. of subjects taking placebo who suffered an MI: 15 menNo. of subjects taking omega 3: 100 menNo. of subjects taking omega 3 who suffered an MI: 5 menCompute for the absolute risk in the treatment (omega 3) group.
Your Answer: 0.05
Explanation:The absolute risk (AR) is the probability or chance of an event. It is computed as the number of events in treated or control groups, divided by the number of people in that group.AR = 5/100 = 0.05
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This question is part of the following fields:
- Evidence Based Medicine
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Question 98
Correct
-
Nitric oxide release from endothelium is stimulated by all of the following EXCEPT for:
Your Answer: Noradrenaline
Explanation:Nitric oxide (NO) production by the endothelium is increased by factors that elevate intracellular Ca2+, including local mediators such as bradykinin, histamine and serotonin, and some neurotransmitters (e.g. substance P). Increased flow (shear stress) also stimulates NO production and additionally activates prostacyclin synthesis. The basal production of NO continuously modulates vascular resistance; increased production of nitric oxide acts to cause vasodilation. Nitric oxide also inhibits platelet activation and thrombosis.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 99
Incorrect
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All of the following statement are correct regarding endothelium derived nitric oxide except:
Your Answer: Nitric oxide inhibits platelet activation and thrombosis.
Correct Answer: Nitric oxide production is inhibited by local mediators such as bradykinin, histamine and serotonin.
Explanation:Factors that elevate intracellular Ca2+ increase nitric oxide (NO) production by the endothelium included local mediators such as histamine and serotonin, bradykinin, and some neurotransmitters like substance P. NO production is also stimulated by increased flow (shear stress) and additionally activates prostacyclin synthesis. As a result of basal production of NO, there is continuous modulation of vascular resistance and as a result, there is increased production of nitric oxide acts which causes vasodilation. Platelet activation and thrombosis are inhibited by nitric oxide.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 100
Correct
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Which of the following is NOT a typical clinical feature of diabetic ketoacidosis:
Your Answer: Cheyne–Stokes respiration
Explanation:Clinical features of DKA: Symptoms: Polyuria, polydipsia, thirst, lethargy, weight loss, nausea, vomiting, anorexia, abdominal pain, dehydration, headache, altered mental stateSigns: Dry mucous membranes, ketotic breath, tachycardia, hypotension, Kussmaul breathing, focal signs of precipitant e.g. infection
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This question is part of the following fields:
- Endocrine
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
