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Question 1
Correct
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What is the mechanism of action of captopril:
Your Answer: Inhibition of the conversion of angiotensin I to angiotensin II
Explanation:Angiotensin-converting enzyme inhibitors (ACE inhibitors) e.g. captopril inhibit the conversion of angiotensin I to angiotensin II, and thus have a vasodilatory effect, lowering both arterial and venous resistance. The cardiac output increases and, because the renovascular resistance falls, there is an increase in renal blood flow. This latter effect, together with reduced aldosterone release, increases Na+ and H2O excretion, contracting the blood volume and reducing venous return to the heart.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 2
Correct
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A 61-year-old woman returns to get the results of recent blood tests she had done for non-specific malaise, lethargy, and weight loss. The only abnormality discovered during the blood tests was a 580 x 10 9 /l increase in platelets. Her platelets were also elevated on a blood test taken 6 months earlier, according to her previous results. You're aware of the recent emergence of elevated platelet levels as a cancer risk marker and decide to look into it.Which of the following cancers is most likely to cause isolated thrombocytosis?
Your Answer: Colorectal cancer
Explanation:Raised platelet levels have emerged as a cancer risk marker, according to a large population-based study published in 2017(link is external). According to the study, 12 percent of men and 6% of women with thrombocytosis were diagnosed with cancer within a year. These figures increased to 18% in men and 10% in women if a second platelet count was taken within 6 months of the first and showed an increased or stable elevated platelet count.The researchers discovered that thrombocytosis linked to cancer is most common in colorectal and lung cancers, and it is linked to a worse prognosis. Furthermore, one-third of the cancer patients in the study had no other symptoms that would have prompted an immediate cancer referral.The exact mechanism by which these cancers cause thrombocytosis is unknown, but one theory proposes the existence of pathogenic feedback loops between malignant cells and platelets, with a reciprocal interaction between tumour growth and metastasis, as well as thrombocytosis and platelet activation. Another hypothesis is that thrombocytosis occurs independently of cancer but aids in its spread and progression.The findings show that routinely testing for thrombocytosis could cut the time it takes to diagnose colorectal and lung cancer by at least two months. In the UK, this could result in around 5500 earlier cancer diagnoses per year.Because the positive predictive value of thrombocytosis in middle age for cancer (10%) is higher than the positive predictive value for a woman in her 50s presenting with a new breast lump (8.5%), this is clearly an important research paper that should be used to adjust future clinical practise. The current NICE guidelines predate these new research findings, so we’ll have to wait and see how they affect cancer referral guidelines in the UK.Because there are so many possible cancers associated with thrombocytosis, the treating clinician should take a thorough history and perform a thorough clinical examination if a patient is diagnosed with it. Further investigation and the most appropriate referral route should be aided by this information.It’s worth noting that the patients in the study had their blood tests done for a medical reason rather than as a random screening test.If there are no other symptoms to guide investigation and referral (one-third of the patients in the study had no other symptoms), keep in mind that the two most common cancers encountered were colorectal and lung cancer, so a chest X-ray and a faecal immunochemical test (FIT) for faecal blood may be reasonable initial investigations.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 3
Correct
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Which of the following is NOT a function of bile:
Your Answer: Digestion of fats into monoglycerides and fatty acids.
Explanation:Bile functions to eliminate endogenous and exogenous substances from the liver (including bilirubin), to neutralise gastric acid in the small intestine, and to emulsify fats in the small intestine and facilitate their digestion and absorption. Bile salts also act as bactericides, destroying many of the microbes that may be present in the food. Bile doesn’t contain digestive enzymes for digestion of lipids into monoglycerides and fatty acids; this is performed mainly by pancreatic lipase.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 4
Correct
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A 15-year-old boy was brought to the emergency room with complaints of a headache, stiffness of the neck, and photophobia. Upon observation, the following were noted: HR 124, BP 86/43, RR 30, SaO 95%, temperature 39.5 deg C. A recently developed non-blanching rash on his legs was also observed.What is most likely the causative agent of the case presented above?
Your Answer: Neisseria meningitidis group B
Explanation:The meningococcus is solely a human pathogen, and up to 50% of the population may carry meningococci in the nasopharynx. Factors that lead to invasion and production of disease include complex inter-relationships of genetic predisposition, host status, environmental conditions, and virulence of the organism.Meningococcal disease is the most common infectious cause of death in childhood in developed countries. It presents as septicaemia, meningitis, or a combination. Septicaemia is the more dangerous presentation, especially with septic shock; meningitis is more likely to lead to neurodevelopmental sequelae. Classic features of septicaemia are a non-blanching rash in a feverish, ill child.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 5
Correct
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Regarding V/Q mismatch, which of the following statements is CORRECT:
Your Answer: In a true shunt, increasing inspired oxygen has no effect on improving hypoxaemia.
Explanation:Both ventilation and perfusion increase towards the lung base, because of the effects of gravity, but the gravitational effects are greater on perfusion than ventilation and therefore there is a regional variation in V/Q ratio from lung apex (high V/Q) to lung base (low V/Q). In a pure shunt, there is normal perfusion but absent ventilation and the V/Q ratio = 0. In a true shunt increasing oxygen fraction has no effect because the oxygen-enriched air fails to reach the shunted blood. An increased A-a gradient is seen in V/Q mismatch.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 6
Correct
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Regarding probability distribution, which of the following statements is CORRECT:
Your Answer: In a negative skew, the mass of distribution is concentrated on the right.
Explanation:Distribution of data is usually unimodal (one peak) but may be bimodal (two peaks) or uniform (no peaks, each value equally likely). The normal distribution is a symmetrical bell-shaped curve. The mean, median, and mode of a normal distribution are equal. In a positive skew, the right tail is longer and the mass of distribution is concentrated on the left; mean > median > mode. In a negative skew, the left tail is longer and the mass of distribution is concentrated on the right; mean < median < mode.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 7
Correct
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ACE inhibitors are indicated for all of the following EXCEPT for:
Your Answer: Angina
Explanation:ACE inhibitors have many uses and are generally well tolerated. They are indicated for:Heart failureHypertensionDiabetic nephropathySecondary prevention of cardiovascular events
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 8
Correct
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A 35 year old patient presents to ED having sustained an injury to his right hand whilst playing cricket. He is unable to fully straighten his right middle finger as the distal phalanx remains flexed. Which of the following structures within the digit was most likely injured:
Your Answer: Insertion of terminal extensor digitorum tendon
Explanation:Damage to the insertion of the terminal extensor digitorum tendon would result in loss of extension at the distal interphalangeal joint causing a fixed flexion deformity, called the Mallet deformity.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 9
Correct
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What is the primary mode of action of Enoxaparin?
Your Answer: Inhibits factor Xa
Explanation:Heparin acts as an anticoagulant by enhancing the inhibition rate of clotting proteases by antithrombin III impairing normal haemostasis and inhibition of factor Xa. Low molecular weight heparins have a small effect on the activated partial thromboplastin time and strongly inhibit factor Xa. Enoxaparin is derived from porcine heparin that undergoes benzylation followed by alkaline depolymerization.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 10
Correct
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Which of the following is first-line for management of status epilepticus:
Your Answer: Intravenous lorazepam
Explanation:First-line treatment is with intravenous lorazepam if available. Intravenous diazepam is effective but it carries a high risk of thrombophlebitis so should only be used if intravenous lorazepam is not immediately available. Absorption of diazepam from intramuscular injection or from suppositories is too slow for treatment of status epilepticus. When facilities for resuscitation are not immediately available or if unable to secure immediate intravenous access, diazepam can be administered as a rectal solution or midazolam oromucosal solution can be given into the buccal cavity.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 11
Correct
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Regarding the phases of gastric secretion, which of the following statements is INCORRECT:
Your Answer: A high pH in the stomach inhibits gastrin secretion.
Explanation:A low pH in the stomach inhibits gastrin secretion, therefore when the stomach is empty or when acid has been secreted for some time after food has entered it, there is inhibition of acid secretion. However, when food first enters the stomach, the pH rises, and this leads to release of the inhibition and causes a maximum secretion of gastrin. Thus gastric acid secretion is self-regulating.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 12
Correct
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Regarding folate requirements, which of the following statements is CORRECT:
Your Answer: Dietary folate is found particularly in leafy green vegetables and liver.
Explanation:Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the growth stage to the mitosis stage. This leads to continuing cell growth without division, which presents as macrocytosis, with an increase in mean corpuscular volume (MCV). The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically vitamin B12 deficiency or folate deficiency.Folate is an essential vitamin found in most foods, especially liver, green vegetables and yeast. The normal daily diet contains 200 – 250 μg, of which about 50% is absorbed. Daily adult requirements are about 100 μg. Absorption of folate is principally from the duodenum and jejunum. Stores of folate are normally only adequate for 4 months and so features of deficiency may be apparent after this time.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 13
Incorrect
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A young female was diagnosed with a urinary tract infection and was sent home with medications. However, after 48 hours of discharge, she returned to the hospital because there had been no relief from her symptoms. The urine sensitivity test report is still unavailable. Fresh blood tests were sent, and her estimated GFR is calculated to be >60 ml/minute. She was prescribed nitrofurantoin 100 mg modified-release orally twice a day for two days.Out of the following, which antibiotic is most appropriate to be prescribed to this patient?
Your Answer: Ciprofloxacin
Correct Answer: Fosfomycin
Explanation:The NICE guidelines for women with lower UTIs who are not pregnant are:1. Consider prescribing a different antibiotic if symptoms do not improve within 48 hours or worsen at any time 2. If the urine culture and susceptibility test results are available, review the choice of antibiotic according to the results and change the antibiotic accordingly if symptoms are not improving or bacteria is resistant to the prescribed antibioticThe first choice of antibiotics for non-pregnant women aged 16 years and over is:1. Nitrofurantoin100 mg modified-release PO BD for 3 days – if eGFR >45 ml/minute2. Trimethoprim 200 mg PO BD for three daysThe second-choice (no improvement in lower UTI symptoms on first-choice for at least 48 hours, or when first-choice is not suitable) are:1. Nitrofurantoin100 mg modified-release PO BD for three days – if eGFR >45 ml/minute2. Pivmecillinam400 mg PO initial dose, then 200 mg PO TDS for three days3. Fosfomycin 3 g single sachet dose
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 14
Incorrect
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Antidiuretic hormone (ADH) has which of the following effects:
Your Answer: Increases fluid reabsorption in the proximal tubule via the insertion of aquaporin water channels
Correct Answer: Increases urine osmolality
Explanation:ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, raising cAMP levels and causing intracellular vesicles to fuse with the apical membrane. In their membrane these vesicles have water channels called aquaporins, which increase the water permeability allowing greater water reabsorption and concentration of urine. ADH also binds to V1 receptor receptors on vascular smooth muscle, causing vasoconstriction and enhancing the effect of aldosterone on sodium reabsorption in the distal tubule. ADH release is stimulated primarily by raised plasma osmolality detected by osmoreceptors in the anterior hypothalamus. Other factors that increase ADH release include: extracellular fluid volume depletion, angiotensin II, nausea, pain, stress, exercise, emotion, hypoglycaemia. ADH release is inhibited by low plasma osmolality, alcohol, caffeine, glucocorticoids and atrial natriuretic peptide (ANP). ADH deficiency (or an inadequate response to ADH) results in diabetes insipidus. Excess levels of ADH results in syndrome of inappropriate ADH secretion (SIADH).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 15
Incorrect
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Among the following infectious diseases, which is typically considered to have an incubation period of less than 3 weeks?
Your Answer: Infectious mononucleosis
Correct Answer: Diphtheria
Explanation:C. diphtheriae, which is the causative agent of diphtheria, is carried in the upper respiratory tract and spread by droplet infection or hand-to-mouth contact. The incubation period averages 2 to 5 days.Infectious mononucleosis is caused by Epstein-Barr virus (EBV). The incubation period for EBV varies from 2 weeks to 2 months.The incubation for Hepatitis A virus is approximately 1 month.The incubation period for Hepatitis C ranges from 2 weeks to 6 months.The period from infection to development of anti-HIV antibodies is usually less than 1 month but may be up to 3 months.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 16
Correct
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Which of the following statements regarding the pituitary gland is CORRECT:
Your Answer: Cortisol inhibits release of adrenocorticotropic hormone (ACTH) from the anterior pituitary.
Explanation:Anterior pituitary hormones are released under the control of hypothalamic releasing or inhibiting hormones originating from small neurons with their cell bodies in the hypothalamus and released into the blood at the median eminence. These hypothalamic hormones are transported directly to the anterior pituitary via hypophyseal portal vessels. The anterior pituitary hormones (and the hormones released by their target organs) inhibit further release of hypothalamic and anterior pituitary hormones by negative feedback mechanisms e.g. cortisol inhibits the release of ACTH. Prolactin release from the anterior pituitary is inhibited by dopamine.The posterior pituitary is really a direct extension of the hypothalamus. Oxytocin and ADH are manufactured in the cell bodies of large neurons in the hypothalamus and are transported down the axons of these cells to their terminals on capillaries originating from the inferior hypophyseal artery within the posterior pituitary gland. ADH release is controlled by negative feedback mechanisms based on plasma osmolality and blood volume, oxytocin however is involved in positive feedback mechanisms.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 17
Correct
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What proportion of peripheral blood leukocytes are monocytes?
Your Answer: 5 - 10%
Explanation:Monocytes account for around 5 to 10% of peripheral white cells. Monocytes in peripheral blood are generally bigger than other leukocytes and feature a large central oval or indented nucleus with clumped chromatin. The abundant cytoplasm staining blue and containing numerous fine vacuoles gives the appearance of ground glass. Cytoplasmic granules are another type of granule. Monocytes evolve from the granulocyte-macrophage progenitor to become monoblasts, promonocytes, monocytes, and tissue macrophages (in increasing order of maturity). Monocytes only stay in the bone marrow for a short time before exiting to circulate in the bloodstream for 20-40 hours before becoming macrophages.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 18
Correct
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A 68-year-old female has presented to the Emergency Department with chest pain, palpitations, and breathlessness complaints. On ECG, she is diagnosed with ventricular arrhythmia and is administered lidocaine. Which of the following is the correct mechanism of action of lidocaine?
Your Answer: Blocks Na+ channels in the heart
Explanation:Lidocaine is a tertiary amide local anaesthetic and also a class IV antiarrhythmic.Like other local anaesthetics, lidocaine works on the voltage-gated sodium ion channel on the nerve cell membranes. It works in the following steps:1. diffuses through neural sheaths and the axonal membrane into the axoplasm2. binds fast voltage-gated Na+ channels in the neuronal cell membrane and inactivates them3. With sufficient blockage, the membrane of the postsynaptic neuron will not depolarise and will be unable to transmit an action potential, thereby preventing the transmission of pain signalsThe same principle applies to Lidocaine’s actions in the heart as it blocks the sodium channels in the conduction system and the myocardium. This raises the threshold for depolarizing, making it less likely for the heart to initiate or conduct any action potential that can cause arrhythmia.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 19
Correct
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All of the following typically occurs as part of normal inspiration except:
Your Answer: Contraction of the internal intercostal muscles
Explanation:Passive inspiration is a result of contraction of the diaphragm (depressing the diaphragm) and the external intercostal muscles (elevating the ribs). In inspiration, several movements occur. These are:1. elevation of the sternal ends of the ribs (‘pump handle’ movement), 2. elevation of the lateral shafts of the ribs (‘bucket handle’ movement) 3. depression of the diaphragm. These result in expansion of the thorax in an anteroposterior, transverse and vertical direction respectively. There is an increased intrathoracic volume and decreased intrathoracic pressure and air is drawn into the lungs.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 20
Incorrect
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Which of the following best describes the popliteal artery's course?
Your Answer: Terminates as the posterior tibial and the fibular artery
Correct Answer: After exiting the popliteal fossa terminates at the lower border of the popliteus muscle
Explanation:The popliteal artery divides into the anterior and posterior tibial arteries at the lower border of the popliteus after exiting the popliteal fossa between the gastrocnemius and popliteus muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 21
Correct
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If a lesion is observed in Broca's area, which function is expected to become affected?
Your Answer: Formation of words
Explanation:The primary functions of the Broca area are both language production and comprehension. While the exact role in the production is still unclear, many believe that it directly impacts the motor movements to allow for speech. Although originally thought to only aid in speech production, lesions in the area can rarely be related to impairments in the comprehension of language. Different regions of the Broca area specialize in various aspects of comprehension. The anterior portion helps with semantics, or word meaning, while the posterior is associated with phonology, or how words sound. The Broca area is also necessary for language repetition, gesture production, sentence grammar and fluidity, and the interpretation of others’ actions.Broca’s aphasia is a non-fluent aphasia in which the output of spontaneous speech is markedly diminished and there is a loss of normal grammatical structure. Specifically, small linking words, conjunctions, such as and, or, and but, and the use of prepositions are lost. Patients may exhibit interjectional speech where there is a long latency, and the words that are expressed are produced as if under pressure. The ability to repeat phrases is also impaired in patients with Broca’s aphasia. Despite these impairments, the words that are produced are often intelligible and contextually correct. In pure Broca’s aphasia, comprehension is intact.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 22
Incorrect
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A 79-year-old male had a humeral shaft fracture during a road traffic accident and is being followed up in a fracture clinic. He complains of inability to use the limb 6 months after the injury. X-rays of that arm shows non union of his fracture.All the following are responsible for this non-union EXCEPT?
Your Answer: Infection
Correct Answer: Osteoporosis
Explanation:An imbalance between bone resorption and formation is Osteoporosis. In normal bone, formation and resorption are roughly equal, and the density of bone matrix remains constant but there is more resorption in osteoporosis and the matrix density reduces and bones become weaker. Fractures are more likely to occur but healing is unaffected. Non-union of a fracture occurs when the two sides of a fracture fail to unite after 6 months. Causes include: infection, movement at the fracture site, avascular necrosis, tissue interposed between the fracture and gross misalignment.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 23
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 24
Correct
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When there is the presence of distended and engorged veins in the umbilical area, which of the following portosystemic anastomoses has most likely occurred?
Your Answer: Para-umbilical veins and inferior epigastric vein
Explanation:Caput medusae is a condition that consists of collateral veins radiating from the umbilicus and results from recanalization of the umbilical vein.Under normal conditions, the portal venous blood traverses the liver and drains into the inferior vena cava of the systemic venous circulation by way of the hepatic veins. This is the direct route. However, other, smaller communications exist between the portal and systemic systems, and they become important when the direct route becomes blocked. These communications are as follows:At the lower third of the oesophagus, the oesophageal branches of the left gastric vein (portal tributary) anastomose with the oesophageal veins draining the middle third of the oesophagus into the azygos veins (systemic tributary).Halfway down the anal canal, the superior rectal veins (portal tributary) draining the upper half of the anal canal anastomosis with the middle and inferior rectal veins (systemic tributaries), which are tributaries of the internal iliac and internal pudendal veins, respectively.The paraumbilical veins connect the left branch of the portal vein with the superficial veins of the anterior abdominal wall (systemic tributaries). The paraumbilical veins travel in the falciform ligament and accompany the ligamentum teres.The veins of the ascending colon, descending colon, duodenum, pancreas, and liver (portal tributary) anastomose with the renal, lumbar, and phrenic veins (systemic tributaries).
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 25
Correct
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The neurotransmitter in the synaptic cleft is either eliminated or deactivated after the postsynaptic cell responds to the neurotransmitter.Which of the following enzymes catalyses the breakdown of noradrenaline?
Your Answer: Catechol-O-methyltransferase (COMT)
Explanation:The neurotransmitter in the synaptic cleft is either eliminated or deactivated after the post-synaptic cell responds to the neurotransmitter. This can be accomplished in a variety of ways:Re-uptakeBreakdownDiffusionSerotonin is an example of a neurotransmitter that is uptake. Serotonin is absorbed back into the presynaptic neuron via the serotonin transporter (SERT), which is found in the presynaptic membrane. Re-uptake neurotransmitters are either recycled by repackaging into vesicles or broken down by enzymes.Specific enzymes found in the synaptic cleft can also break down neurotransmitters. The following enzymes are examples of these enzymes:Acetylcholinesterase (AChE) catalyses the acetylcholine breakdown (ACh)The enzyme catechol-O-methyltransferase (COMT) catalyses the breakdown of catecholamines like adrenaline , dopamine and noradrenaline. The breakdown of catecholamines, as well as other monoamines like serotonin, tyramine, and tryptamine, is catalysed by monoamine oxidases (MOA).Diffusion of neurotransmitters into nearby locations can also be used to eliminate them.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 26
Correct
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Which of the following would you NOT expect from a deep fibular nerve palsy:
Your Answer: Loss of sensation over heel
Explanation:Damage to the deep fibular nerve results in loss of dorsiflexion of the ankle, with resultant foot drop with high-stepping gait, loss of toe extension, weakness of foot inversion and loss of sensation over the webspace between the 1st and 2nd toes.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 27
Correct
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Gastrin release from antral G-cells is stimulated by all but which one of the following:
Your Answer: Secretin
Explanation:Gastrin secretion is stimulated by: The presence of small peptides and amino acids in chymeGastric distensionVagal stimulation directly via acetylcholine and indirectly via gastrin-releasing peptide (GRP)Raised gastric pH
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 28
Correct
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Regarding gastric motility and emptying, which of the following statements is CORRECT:
Your Answer: Gastric emptying is inhibited by the presence of the products of fat digestion in the duodenum.
Explanation:Gastric emptying is decreased by the presence of fats in the duodenum (by stimulating release of cholecystokinin). Mixing of the food with gastric secretions takes place in the distal body and antrum of the stomach where the muscularis externa layer is thicker. The stomach has an additional inner oblique smooth muscle layer (in addition to the inner circular layer and outer longitudinal layer). Gastric emptying is increased by a low gastric pH and decreased by a low duodenal pH.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 29
Correct
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A 62-year-old woman presents with cold sensitivity, tiredness, and weight gain. A series of blood tests done shows a grossly elevated TSH level and a diagnosis of hypothyroidism is made.What is the commonest cause of hypothyroidism worldwide?
Your Answer: Iodine deficiency
Explanation:Hypothyroidism occurs when there is a deficiency of circulating thyroid hormones. It is commoner in women and is most frequently seen in the age over 60.Iodine deficiency is the commonest cause of hypothyroidism worldwide.In the UK and other developed countries, iodine deficiency is not a problem and autoimmune thyroiditis is the commonest cause.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 30
Incorrect
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Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer: It is not found in normal intestinal flora.
Correct Answer: Infection is predominantly derived from animal faeces and soil.
Explanation:Clostridium tetaniis a Gram positive, rod shaped, obligate anaerobic bacterium.The incubation period is quoted as anywhere between 4-21 days and can occur after several months but symptoms usually occur within the first 7 days after exposure.Approximately 80% of patients develop generalised tetanus. The commonest presenting feature of generalised tetanus is trismus (lockjaw), occurring in approximately 75% of affected individuals. Other clinical features include:Facial spasms (risus sardonicus)Opisthotonus (characteristic body shape during spasms)Neck stiffnessDysphagiaCalf and pectoral muscle rigidityFeverHypertensionTachycardiaSpasms can occur frequently and last for several minutes, they can continue to occur for up to 4 weeks. Current mortality rates are between 10 and 15%.Tetanic spasms are caused by the exotoxin tetanospasmin. The effects of tetanolysin are not fully understood but it is not believed to have clinical significance.Localised tetanus is a rare form of the disease, occurring in around 1% of affected individuals. Patients have persistent contraction of muscles in the same anatomic area as the injury. It may precede generalised tetanus.
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This question is part of the following fields:
- Microbiology
- Pathogens
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