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Question 1
Correct
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A 50-year-old woman visits her doctor with concerns about her vision. She reports experiencing double vision and had a recent fall while descending the stairs at her home. She denies experiencing any eye pain.
Which cranial nerve is most likely responsible for her symptoms?Your Answer: Trochlear nerve
Explanation:If you experience worsened vision while descending stairs, it may be indicative of 4th nerve palsy, which is characterized by vertical diplopia. This is because the 4th nerve is responsible for downward eye movement.
Understanding Fourth Nerve Palsy
Fourth nerve palsy is a condition that affects the superior oblique muscle, which is responsible for depressing the eye and moving it inward. One of the main features of this condition is vertical diplopia, which is double vision that occurs when looking straight ahead. This is often noticed when reading a book or going downstairs. Another symptom is subjective tilting of objects, also known as torsional diplopia. Patients may also develop a head tilt, which they may or may not be aware of. When looking straight ahead, the affected eye appears to deviate upwards and is rotated outwards. Understanding the symptoms of fourth nerve palsy can help individuals seek appropriate treatment and management for this condition.
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This question is part of the following fields:
- Neurological System
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Question 2
Correct
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A 4-year-old girl is rushed to the emergency department by her father due to breathing difficulties. He suspects that she may have ingested a small toy while he was not looking.
Which of the following statements accurately describes the lower respiratory tract?Your Answer: The right main bronchus is more vertical than the left
Explanation:Anatomy of the Bronchial Tree
The trachea divides into two bronchi at the sternal angle, with the right bronchus being wider, shorter, and more vertical than the left. This anatomical difference makes it more likely for foreign objects to become lodged in the right bronchus. However, this difference only occurs after the age of one, so younger children are at equal risk for foreign body aspiration in either bronchus.
Each main bronchus further divides into lobar bronchi, with the left having two and the right having three. These lobar bronchi then give rise to tertiary or segmental bronchi, which supply a specific bronchopulmonary segment. These segments are anatomically and functionally separate from each other and can be removed without affecting the surrounding lung tissue.
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This question is part of the following fields:
- Clinical Sciences
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Question 3
Correct
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A 79-year-old male arrives at the emergency department with sudden onset right sided hemiparesis. He has a medical history of hypertension and reports no changes to his vision, speech or hearing.
What is the probable diagnosis?Your Answer: Lacunar infarct
Explanation:A lacunar stroke can lead to isolated hemiparesis, hemisensory loss, or hemiparesis with limb ataxia. In this case, the patient is experiencing isolated hemiparesis, which is likely caused by a lacunar infarct. Hypertension is strongly linked to this type of stroke.
Weber’s syndrome results in CN III palsy on the same side as the stroke and weakness in the opposite limb.
Nystagmus is a common symptom of Wallenberg syndrome.
Ipsilateral deafness is a common symptom of lateral pontine syndrome.
Stroke can affect different parts of the brain depending on which artery is affected. If the anterior cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the lower extremities being more affected than the upper. If the middle cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the upper extremities being more affected than the lower. They may also experience vision loss and difficulty with language. If the posterior cerebral artery is affected, the person may experience vision loss and difficulty recognizing objects.
Lacunar strokes are a type of stroke that are strongly associated with hypertension. They typically present with isolated weakness or loss of sensation on one side of the body, or weakness with difficulty coordinating movements. They often occur in the basal ganglia, thalamus, or internal capsule.
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This question is part of the following fields:
- Neurological System
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Question 4
Incorrect
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A 65-year-old male presents with a six month history of weight loss and tiredness. He is a smoker of 10 cigarettes per day and drinks approximately 10 units of alcohol daily.
On examination, he appears slightly plethoric, but otherwise has no obvious abnormality. Investigations reveal a haemoglobin level of 202 g/L (130-180), platelets of 310 ×109/L (150-400), and a white cell count of 9.2 ×109/L (4-11). His U+Es are normal and his glucose level is 5.5 mmol/L (3.0-6.0). Urine analysis reveals blood 2+.
What is the most appropriate investigation for this patient that will aid in the diagnosis?Your Answer: Bone marrow examination
Correct Answer: Abdominal ultrasound scan
Explanation:Salient Features and Possible Causes of Polycythaemia
The patient presents with weight loss, no obvious physical abnormalities, and a polycythaemia with 2+ blood on dipstick analysis. These symptoms suggest the need for investigation of a genitourinary (GU) malignancy, with an ultrasound abdomen being the most appropriate test. It is important to note that smoking may cause polycythaemia, but it could also be caused by a hypernephroma that produces ectopic erythropoietin. Therefore, further investigation is necessary to determine the underlying cause of the patient’s polycythaemia.
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This question is part of the following fields:
- Renal System
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Question 5
Correct
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A passionate surgical resident attempts his first independent splenectomy. The procedure proves to be more challenging than expected and the resident places a tube drain in the splenic bed at the conclusion of the surgery. Within the next 24 hours, around 500ml of clear fluid drains into the tube. What is the most probable result of biochemical testing on the fluid?
Elevated creatinine
28%
Elevated triglycerides
10%
Elevated glucagon
9%
Elevated amylase
25%
None of the above
29%
During a splenectomy, the tail of the pancreas may be harmed, causing the pancreatic duct to drain into the splenic bed, resulting in an increase in amylase levels. Glucagon is not produced in the pancreatic duct.Your Answer: Elevated amylase
Explanation:If the tail of the pancreas is damaged during splenectomy, the pancreatic duct may end up draining into the splenic bed. This can result in an increase in amylase levels, but there will be no secretion of glucagon into the pancreatic duct.
Understanding the Anatomy of the Spleen
The spleen is a vital organ in the human body, serving as the largest lymphoid organ. It is located below the 9th-12th ribs and has a clenched fist shape. The spleen is an intraperitoneal organ, and its peritoneal attachments condense at the hilum, where the vessels enter the spleen. The blood supply of the spleen is from the splenic artery, which is derived from the coeliac axis, and the splenic vein, which is joined by the IMV and unites with the SMV.
The spleen is derived from mesenchymal tissue during embryology. It weighs between 75-150g and has several relations with other organs. The diaphragm is superior to the spleen, while the gastric impression is anterior, the kidney is posterior, and the colon is inferior. The hilum of the spleen is formed by the tail of the pancreas and splenic vessels. The spleen also forms the apex of the lesser sac, which contains short gastric vessels.
In conclusion, understanding the anatomy of the spleen is crucial in comprehending its functions and the role it plays in the human body. The spleen’s location, weight, and relations with other organs are essential in diagnosing and treating spleen-related conditions.
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This question is part of the following fields:
- Gastrointestinal System
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Question 6
Correct
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A 25-year-old male presents to his GP with recurrent episodes of haematuria. He reports having a sore throat and mild cough for the past three days. Upon examination, his urine dipstick is negative for leukocytes and nitrates. His vital signs are as follows: SpO2 99%, respiratory rate 16/min, blood pressure 140/90mmHg, heart rate 80bpm, and temperature 37.1ºC. The initial blood results show a Hb of 14.8 g/dL, platelets of 290 * 109/L, WBC of 14.9 * 109/L, Na+ of 138 mmol/L, K+ of 4.5 mmol/L, urea of 7.2 mmol/L, creatinine of 150 µmol/L, and CRP of 1.2 mg/L. What is the most likely mechanism responsible for his haematuria?
Your Answer: Immune complex deposition
Explanation:The likely diagnosis for the man is IgA nephropathy, which is characterized by immune complex deposition in the glomerulus and recurrent macroscopic haematuria following an upper respiratory tract infection. Disseminated intravascular coagulation (DIC) caused by activation of the coagulation cascade and damage from toxins such as Shiga toxin in haemolytic uraemic syndrome are not responsible mechanisms for IgA nephropathy. Benign prostatic hypertrophy (BPH), which is caused by hypertrophy of prostatic cells, can also cause haematuria, but it is unlikely in this patient as it typically affects older men and presents with other urinary symptoms.
Understanding IgA Nephropathy
IgA nephropathy, also known as Berger’s disease, is the most common cause of glomerulonephritis worldwide. It typically presents as macroscopic haematuria in young people following an upper respiratory tract infection. The condition is thought to be caused by mesangial deposition of IgA immune complexes, and there is considerable pathological overlap with Henoch-Schonlein purpura (HSP). Histology shows mesangial hypercellularity and positive immunofluorescence for IgA and C3.
Differentiating between IgA nephropathy and post-streptococcal glomerulonephritis is important. Post-streptococcal glomerulonephritis is associated with low complement levels and the main symptom is proteinuria, although haematuria can occur. There is typically an interval between URTI and the onset of renal problems in post-streptococcal glomerulonephritis.
Management of IgA nephropathy depends on the severity of the condition. If there is isolated hematuria, no or minimal proteinuria, and a normal glomerular filtration rate (GFR), no treatment is needed other than follow-up to check renal function. If there is persistent proteinuria and a normal or only slightly reduced GFR, initial treatment is with ACE inhibitors. If there is active disease or failure to respond to ACE inhibitors, immunosuppression with corticosteroids may be necessary.
The prognosis for IgA nephropathy varies. 25% of patients develop ESRF. Markers of good prognosis include frank haematuria, while markers of poor prognosis include male gender, proteinuria (especially > 2 g/day), hypertension, smoking, hyperlipidaemia, and ACE genotype DD.
Overall, understanding IgA nephropathy is important for proper diagnosis and management of the condition. Proper management can help improve outcomes and prevent progression to ESRF.
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This question is part of the following fields:
- Renal System
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Question 7
Incorrect
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The following result is obtained on a 48-year-old male who is admitted with acute onset chest pain:
Serum Cholesterol 7.3 mmol/L (<5.2)
He has a strong family history of ischaemic heart disease.
What abnormalities might be expected upon examination of this man?Your Answer:
Correct Answer: Tendon nodules
Explanation:Familial Hypercholesterolaemia and its Manifestations
Familial hypercholesterolaemia is a condition characterized by high levels of cholesterol in the blood. This condition is often indicated by the deposition of cholesterol in various parts of the body. The history of the patient suggests that they may be suffering from familial hypercholesterolaemia. The deposition of cholesterol can be observed around the corneal arcus, around the eye itself (xanthelasma), and in tendons such as achilles, knuckles or triceps tendons (tendon xanthomas).
While dietary and lifestyle modifications are recommended, they are usually not enough to manage the condition. High dose lifelong statin therapy is often necessary to control the levels of cholesterol in the blood. It is important to seek medical attention and follow the recommended treatment plan to prevent further complications associated with familial hypercholesterolaemia. The National Institute for Health and Care Excellence (NICE) recommends the use of statin therapy in conjunction with lifestyle modifications for the management of familial hypercholesterolaemia.
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This question is part of the following fields:
- Pharmacology
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Question 8
Incorrect
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Isabella is an 82-year-old female who visits the cardiology clinic for a check-up. She experienced a heart attack half a year ago and has been experiencing swollen ankles and difficulty breathing when lying down. You suspect heart failure and arrange for an echocardiogram, prescribe diuretic medications, and conduct a blood test. What blood marker can indicate excessive stretching of the heart muscle?
Your Answer:
Correct Answer: Brain natriuretic peptide (BNP)
Explanation:BNP is produced by the ventricles of the heart when the cardiomyocytes are excessively stretched. Its overall effect is to reduce blood pressure by decreasing systemic vascular resistance and increasing natriuresis.
Troponin is a protein that plays a role in cardiac muscle contraction and is a specific and sensitive marker for myocardial damage in cases of myocardial infarction.
Creatine kinase and LDH can be used as acute markers for myocardial infarction.
Myoglobin is released after muscle damage, but it is not specific to acute myocardial infarction and is typically measured in cases of rhabdomyolysis.
B-type natriuretic peptide (BNP) is a hormone that is primarily produced by the left ventricular myocardium in response to strain. Although heart failure is the most common cause of elevated BNP levels, any condition that causes left ventricular dysfunction, such as myocardial ischemia or valvular disease, may also raise levels. In patients with chronic kidney disease, reduced excretion may also lead to elevated BNP levels. Conversely, treatment with ACE inhibitors, angiotensin-2 receptor blockers, and diuretics can lower BNP levels.
BNP has several effects, including vasodilation, diuresis, natriuresis, and suppression of both sympathetic tone and the renin-angiotensin-aldosterone system. Clinically, BNP is useful in diagnosing patients with acute dyspnea. A low concentration of BNP (<100 pg/mL) makes a diagnosis of heart failure unlikely, but elevated levels should prompt further investigation to confirm the diagnosis. Currently, NICE recommends BNP as a helpful test to rule out a diagnosis of heart failure. In patients with chronic heart failure, initial evidence suggests that BNP is an extremely useful marker of prognosis and can guide treatment. However, BNP is not currently recommended for population screening for cardiac dysfunction.
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This question is part of the following fields:
- Cardiovascular System
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Question 9
Incorrect
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A 32-year-old patient with schizophrenia visits the clinic. He has observed discharge on his shirt twice and upon inspection, he noticed a milky fluid coming from his nipples. He recalls his psychiatrist mentioning that this could happen with his medication. What is the most probable reason for his discharge?
Your Answer:
Correct Answer: Risperidone
Explanation:Hyperprolactinaemia, which is characterized by high levels of prolactin, is a common side effect of certain atypical antipsychotics like risperidone. This medication can cause galactorrhoea, which is the abnormal secretion of milk due to the development of breast tissue and mammary glands.
Different antipsychotics have their own unique side effect profiles, and the most likely culprits of hyperprolactinaemia are haloperidol (a conventional antipsychotic) and risperidone (an atypical antipsychotic). While it is uncommon for most atypical antipsychotics to cause galactorrhoea, risperidone is an exception.
Other antipsychotics like clozapine are associated with agranulocytosis and myocarditis, while olanzapine is linked to dyslipidaemia, diabetes mellitus, and weight gain.
Atypical antipsychotics are now recommended as the first-line treatment for patients with schizophrenia, as per the 2005 NICE guidelines. These agents have a significant advantage over traditional antipsychotics in that they cause fewer extrapyramidal side-effects. However, atypical antipsychotics can still cause adverse effects such as weight gain, hyperprolactinaemia, and clozapine-associated agranulocytosis. Elderly patients who take antipsychotics are at an increased risk of stroke and venous thromboembolism, according to the Medicines and Healthcare products Regulatory Agency.
Clozapine is one of the first atypical antipsychotics to be developed, but it carries a significant risk of agranulocytosis. Therefore, full blood count monitoring is essential during treatment. Clozapine should only be used in patients who are resistant to other antipsychotic medication. The BNF recommends introducing clozapine if schizophrenia is not controlled despite the sequential use of two or more antipsychotic drugs, one of which should be a second-generation antipsychotic drug, each for at least 6-8 weeks. Clozapine can cause adverse effects such as reduced seizure threshold, constipation, myocarditis, and hypersalivation. Dose adjustment of clozapine may be necessary if smoking is started or stopped during treatment.
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This question is part of the following fields:
- Psychiatry
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Question 10
Incorrect
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A 35-year-old woman visits her doctor suspecting that she might be pregnant as she has missed her last two menstrual cycles. What hormone is expected to be present in the highest amount if her suspicion is true?
Your Answer:
Correct Answer: Human Chorionic Gonadotropin
Explanation:It is important to be aware of the role that hormones play during pregnancy.
Endocrine Changes During Pregnancy
During pregnancy, there are several physiological changes that occur in the body, including endocrine changes. Progesterone, which is produced by the fallopian tubes during the first two weeks of pregnancy, stimulates the secretion of nutrients required by the zygote/blastocyst. At six weeks, the placenta takes over the production of progesterone, which inhibits uterine contractions by decreasing sensitivity to oxytocin and inhibiting the production of prostaglandins. Progesterone also stimulates the development of lobules and alveoli.
Oestrogen, specifically oestriol, is another major hormone produced during pregnancy. It stimulates the growth of the myometrium and the ductal system of the breasts. Prolactin, which increases during pregnancy, initiates and maintains milk secretion of the mammary gland. It is essential for the expression of the mammotropic effects of oestrogen and progesterone. However, oestrogen and progesterone directly antagonize the stimulating effects of prolactin on milk synthesis.
Human chorionic gonadotropin (hCG) is secreted by the syncitiotrophoblast and can be detected within nine days of pregnancy. It mimics LH, rescuing the corpus luteum from degenerating and ensuring early oestrogen and progesterone secretion. It also stimulates the production of relaxin and may inhibit contractions induced by oxytocin. Other hormones produced during pregnancy include relaxin, which suppresses myometrial contractions and relaxes the pelvic ligaments and pubic symphysis, and human placental lactogen (hPL), which has lactogenic actions and enhances protein metabolism while antagonizing insulin.
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This question is part of the following fields:
- Reproductive System
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Question 11
Incorrect
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A 76-year-old man is experiencing symptoms suggestive of intermittent claudication. You plan to evaluate the extent of his condition by measuring his ankle brachial pressure index. In order to do so, you need to locate the dorsalis pedis artery. Which of the following statements regarding this artery is incorrect?
Your Answer:
Correct Answer: It originates from the peroneal artery
Explanation:The anterior tibial artery continues directly into the dorsalis pedis artery.
The foot has two arches: the longitudinal arch and the transverse arch. The longitudinal arch is higher on the medial side and is supported by the posterior pillar of the calcaneum and the anterior pillar composed of the navicular bone, three cuneiforms, and the medial three metatarsal bones. The transverse arch is located on the anterior part of the tarsus and the posterior part of the metatarsus. The foot has several intertarsal joints, including the sub talar joint, talocalcaneonavicular joint, calcaneocuboid joint, transverse tarsal joint, cuneonavicular joint, intercuneiform joints, and cuneocuboid joint. The foot also has various ligaments, including those of the ankle joint and foot. The foot is innervated by the lateral plantar nerve and medial plantar nerve, and it receives blood supply from the plantar arteries and dorsalis pedis artery. The foot has several muscles, including the abductor hallucis, flexor digitorum brevis, abductor digit minimi, flexor hallucis brevis, adductor hallucis, and extensor digitorum brevis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 12
Incorrect
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As a medical student on a surgical team, the FY1 doctor requests that you conduct a group and save blood test for a patient prior to their operation. The patient, who is identified as being in their 50s, has blood group A and therefore has anti-B antibodies. What type of antibodies will they possess?
Your Answer:
Correct Answer: IgM
Explanation:The IgM antibody is composed of five antibodies joined together and is primarily responsible for clumping antigens. Anti-A and anti-B antibodies are typically IgM and are produced during early childhood due to exposure to environmental factors like bacteria, viruses, and food.
On the other hand, IgG is the most prevalent antibody and exists as a single antibody complex. IgD, on the other hand, is located on the surface of B-lymphocytes.
Blood product transfusion complications can be categorized into immunological, infective, and other complications. Immunological complications include acute haemolytic reactions, non-haemolytic febrile reactions, and allergic/anaphylaxis reactions. Infective complications may arise due to transmission of vCJD, although measures have been taken to minimize this risk. Other complications include transfusion-related acute lung injury (TRALI), transfusion-associated circulatory overload (TACO), hyperkalaemia, iron overload, and clotting.
Non-haemolytic febrile reactions are thought to be caused by antibodies reacting with white cell fragments in the blood product and cytokines that have leaked from the blood cell during storage. These reactions may occur in 1-2% of red cell transfusions and 10-30% of platelet transfusions. Minor allergic reactions may also occur due to foreign plasma proteins, while anaphylaxis may be caused by patients with IgA deficiency who have anti-IgA antibodies.
Acute haemolytic transfusion reaction is a serious complication that results from a mismatch of blood group (ABO) which causes massive intravascular haemolysis. Symptoms begin minutes after the transfusion is started and include a fever, abdominal and chest pain, agitation, and hypotension. Treatment should include immediate transfusion termination, generous fluid resuscitation with saline solution, and informing the lab. Complications include disseminated intravascular coagulation and renal failure.
TRALI is a rare but potentially fatal complication of blood transfusion that is characterized by the development of hypoxaemia/acute respiratory distress syndrome within 6 hours of transfusion. On the other hand, TACO is a relatively common reaction due to fluid overload resulting in pulmonary oedema. As well as features of pulmonary oedema, the patient may also be hypertensive, a key difference from patients with TRALI.
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This question is part of the following fields:
- Haematology And Oncology
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Question 13
Incorrect
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You are a medical student on an endocrine ward. There is a 65-year-old patient on the ward suffering from hypopituitarism. One of the junior doctors explains to you that the patient's pituitary gland was damaged when they received radiation therapy for a successfully treated brain tumour last year. He shows you a CT scan and demonstrates that only the anterior pituitary gland is damaged, with the posterior pituitary gland unaffected.
Which of the following hormones is unlikely to be affected?Your Answer:
Correct Answer: antidiuretic hormone
Explanation:The pituitary gland is a small gland located within the sella turcica in the sphenoid bone of the middle cranial fossa. It weighs approximately 0.5g and is covered by a dural fold. The gland is attached to the hypothalamus by the infundibulum and receives hormonal stimuli from the hypothalamus through the hypothalamo-pituitary portal system. The anterior pituitary, which develops from a depression in the wall of the pharynx known as Rathkes pouch, secretes hormones such as ACTH, TSH, FSH, LH, GH, and prolactin. GH and prolactin are secreted by acidophilic cells, while ACTH, TSH, FSH, and LH are secreted by basophilic cells. On the other hand, the posterior pituitary, which is derived from neuroectoderm, secretes ADH and oxytocin. Both hormones are produced in the hypothalamus before being transported by the hypothalamo-hypophyseal portal system.
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This question is part of the following fields:
- Neurological System
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Question 14
Incorrect
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A 75-year-old male presents with painless frank haematuria. Clinical examination is unremarkable. Routine blood tests reveal a haemoglobin of 190 g/L but are otherwise normal. What is the most probable underlying diagnosis?
Your Answer:
Correct Answer: Adenocarcinoma of the kidney
Explanation:Renal cell carcinoma is often associated with polycythaemia, while Wilms tumours are predominantly found in children.
Causes of Haematuria
Haematuria, or blood in the urine, can be caused by a variety of factors. Trauma to the renal tract, such as blunt or penetrating injuries, can result in haematuria. Infections, including tuberculosis, can also cause blood in the urine. Malignancies, such as renal cell carcinoma or urothelial malignancies, can lead to painless or painful haematuria. Renal diseases like glomerulonephritis, structural abnormalities like cystic renal lesions, and coagulopathies can also cause haematuria.
Certain drugs, such as aminoglycosides and chemotherapy, can cause tubular necrosis or interstitial nephritis, leading to haematuria. Anticoagulants can also cause bleeding of underlying lesions. Benign causes of haematuria include exercise and gynaecological conditions like endometriosis.
Iatrogenic causes of haematuria include catheterisation and radiotherapy, which can lead to cystitis, severe haemorrhage, and bladder necrosis. Pseudohaematuria, or the presence of substances that mimic blood in the urine, can also cause false positives for haematuria. It is important to identify the underlying cause of haematuria in order to provide appropriate treatment and management.
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This question is part of the following fields:
- Gastrointestinal System
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Question 15
Incorrect
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A father brings his 9-year-old daughter to your general practice, as he is worried about her hearing. He notices that he has to repeat himself when talking to her, and thinks she is often 'in her own little world'. During the examination, the Rinne test is positive on the left and negative on the right. What conclusions can be drawn from this?
Your Answer:
Correct Answer: Can not tell if both sides are affected.
Explanation:The Rinne and Weber tests are used to diagnose hearing loss. The Rinne test involves comparing air and bone conduction, with a positive result indicating a healthy or sensorineural loss and a negative result indicating a conductive loss. The Weber test involves placing a tuning fork on the forehead and determining if the sound is symmetrical or louder on one side, with a conductive loss resulting in louder sound on the affected side and a sensorineural loss resulting in louder sound on the non-affected side. When used together, these tests can provide more information about the type and affected side of hearing loss.
Rinne’s and Weber’s Test for Differentiating Conductive and Sensorineural Deafness
Rinne’s and Weber’s tests are used to differentiate between conductive and sensorineural deafness. Rinne’s test involves placing a tuning fork over the mastoid process until the sound is no longer heard, then repositioning it just over the external acoustic meatus. A positive test indicates that air conduction (AC) is better than bone conduction (BC), while a negative test indicates that BC is better than AC, suggesting conductive deafness.
Weber’s test involves placing a tuning fork in the middle of the forehead equidistant from the patient’s ears and asking the patient which side is loudest. In unilateral sensorineural deafness, sound is localized to the unaffected side, while in unilateral conductive deafness, sound is localized to the affected side.
The table below summarizes the interpretation of Rinne and Weber tests. A normal result indicates that AC is greater than BC bilaterally and the sound is midline. Conductive hearing loss is indicated by BC being greater than AC in the affected ear and AC being greater than BC in the unaffected ear, with the sound lateralizing to the affected ear. Sensorineural hearing loss is indicated by AC being greater than BC bilaterally, with the sound lateralizing to the unaffected ear.
Overall, Rinne’s and Weber’s tests are useful tools for differentiating between conductive and sensorineural deafness, allowing for appropriate management and treatment.
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This question is part of the following fields:
- Respiratory System
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Question 16
Incorrect
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A 28-year-old male gives a blood unit that is stored at 4 oC. Which clotting factor will be most impacted after 72 hours?
Your Answer:
Correct Answer: Factor V
Explanation:FFP is frozen shortly after collection due to the temperature sensitivity of factors V and VIII.
Blood Products and Cell Saver Devices
Blood products are essential in various medical procedures, especially in cases where patients require transfusions due to anaemia or bleeding. Packed red cells, platelet-rich plasma, platelet concentrate, fresh frozen plasma, and cryoprecipitate are some of the commonly used whole blood fractions. Fresh frozen plasma is usually administered to patients with clotting deficiencies, while cryoprecipitate is a rich source of Factor VIII and fibrinogen. Cross-matching is necessary for all blood products, and cell saver devices are used to collect and re-infuse a patient’s own blood lost during surgery.
Cell saver devices come in two types, those that wash the blood cells before re-infusion and those that do not. The former is more expensive and complicated to operate but reduces the risk of re-infusing contaminated blood. The latter avoids the use of donor blood and may be acceptable to Jehovah’s witnesses. However, it is contraindicated in malignant diseases due to the risk of facilitating disease dissemination.
In some surgical patients, the use of warfarin can pose specific problems and may require the use of specialised blood products. Warfarin reversal can be achieved through the administration of vitamin K, fresh frozen plasma, or human prothrombin complex. Fresh frozen plasma is used less commonly now as a first-line warfarin reversal, and human prothrombin complex is preferred due to its rapid action. However, it should be given with vitamin K as factor 6 has a short half-life.
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This question is part of the following fields:
- Haematology And Oncology
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Question 17
Incorrect
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A woman in her early pregnancy is diagnosed with anaemia during a routine check-up. She is informed that this is a common occurrence. What causes anaemia to develop during pregnancy?
Your Answer:
Correct Answer: Haemodilution by the increased plasma volume
Explanation:Anaemia in pregnancy results from a greater increase in plasma volume compared to haemoglobin concentration, leading to a dilution of haemoglobin levels. It is important to note that haemoglobin levels actually increase during pregnancy. Drinking more water does not cause anaemia, as any excess water would be eliminated by the kidneys. Additionally, reduced secretion of ADH does not occur during pregnancy and would result in diuresis rather than anaemia.
During pregnancy, women are checked for anaemia twice – once at the initial booking visit (usually at 8-10 weeks) and again at 28 weeks. The National Institute for Health and Care Excellence (NICE) has set specific cut-off levels to determine if a woman requires oral iron therapy. For the first trimester, the cut-off is less than 110 g/L, for the second and third trimesters, it is less than 105 g/L, and for the postpartum period, it is less than 100 g/L. If a woman falls below these levels, she should receive oral ferrous sulfate or ferrous fumarate. Treatment should continue for three months after iron deficiency is corrected to allow for the replenishment of iron stores.
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This question is part of the following fields:
- Reproductive System
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Question 18
Incorrect
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A new antibody test is being researched to aid in the early diagnosis of juvenile rheumatoid arthritis. It has a specificity of 97%.
Which of the following statements is accurate?Your Answer:
Correct Answer: 97% of patients without the condition will have a negative test
Explanation:Precision refers to the consistency of a test in producing the same results when repeated multiple times. It is an important aspect of test reliability and can impact the accuracy of the results. In order to assess precision, multiple tests are performed on the same sample and the results are compared. A test with high precision will produce similar results each time it is performed, while a test with low precision will produce inconsistent results. It is important to consider precision when interpreting test results and making clinical decisions.
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This question is part of the following fields:
- General Principles
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Question 19
Incorrect
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A female infant is born prematurely at 32 weeks gestation by emergency cesarean section. She initially appears to be stable. However, over the ensuing 48 hours she develops worsening neurological function. What is the most probable process that has occurred?
Your Answer:
Correct Answer: Intraventricular haemorrhage
Explanation:Intraventricular haemorrhage is commonly seen in premature neonates, while subdural bleed is often associated with non-accidental injury.
Understanding Intraventricular Haemorrhage
Intraventricular haemorrhage is a rare condition that involves bleeding into the ventricular system of the brain. It is typically associated with severe head injuries in adults, while premature neonates may experience it spontaneously. The exact cause of this condition is not well understood, but it is believed to occur due to birth trauma and cellular hypoxia in neonates. In most cases, IVH occurs within the first 72 hours after birth.
Treatment for intraventricular haemorrhage is largely supportive, and therapies such as intraventricular thrombolysis and prophylactic CSF drainage have not been shown to be effective. If hydrocephalus and rising ICP occur, shunting may be necessary. It is important to monitor patients with IVH closely and provide appropriate care to manage any complications that may arise. By understanding this condition, healthcare professionals can provide better care for patients with intraventricular haemorrhage.
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This question is part of the following fields:
- General Principles
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Question 20
Incorrect
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In which part of the gastrointestinal system is water mainly taken up?
Your Answer:
Correct Answer: Small intestine
Explanation:The Function of the Large Intestine
Although many people believe that the primary function of the large intestine is to absorb water, this is not entirely accurate. In fact, the majority of water and fluids that are ingested or secreted are actually reabsorbed in the small intestine, which is located before the large intestine in the digestive tract. While the large intestine does play a role in absorbing some water and electrolytes, its primary function is to store and eliminate waste products from the body. This is achieved through the formation of feces, which are then eliminated through the rectum and anus. Overall, while the large intestine is an important part of the digestive system, its function is more complex than simply absorbing water.
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This question is part of the following fields:
- Clinical Sciences
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Question 21
Incorrect
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Which substance is not typically found in bile?
Your Answer:
Correct Answer: Glucose
Explanation:The Role and Composition of Bile
Bile plays a crucial role in the excretion of substances that are not easily eliminated by the kidneys, particularly lipid-rich molecules and non-polar substances. Its main components include bile acids or bile salts, cholesterol, phospholipids (such as lecithin), conjugated bilirubin, electrolytes, and a small amount of protein. Glucose is not typically found in bile as it is highly soluble and can be excreted in urine if present in excess in the bloodstream.
Cholesterol is broken down into bile acids, specifically cholic acid and chenodeoxycholic acid, which are then conjugated with proteins like glycine or taurine to form bile salts. Conjugated bilirubin, on the other hand, is a byproduct of the breakdown of haem from haemoglobin and myoglobin. Overall, bile serves as an important mechanism for the elimination of certain substances from the body.
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This question is part of the following fields:
- Clinical Sciences
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Question 22
Incorrect
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How can this question be restated?
Your Answer:
Correct Answer: NMDA receptors are ligand gated ion channels
Explanation:Different Types of Receptors in the Body
There are various types of receptors in the body that play important roles in different physiological processes. One type of receptor is the 5HT3 receptor, which is a ligand gated ion channel. This means that it opens and closes in response to the binding of a specific ligand, allowing ions to flow in and out of the cell. Another type of receptor is the aldosterone receptor, which is a steroid receptor. This receptor binds to the hormone aldosterone and regulates the body’s electrolyte balance.
The β2 adrenoreceptor is another type of receptor, which is a g protein coupled receptor. This receptor is activated by the hormone adrenaline and plays a role in regulating heart rate and bronchodilation. Finally, the insulin receptor is a tyrosine receptor kinase. This receptor is activated by the hormone insulin and plays a crucial role in regulating glucose metabolism in the body. the different types of receptors in the body is important for how different physiological processes are regulated.
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This question is part of the following fields:
- Pharmacology
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Question 23
Incorrect
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A young woman presents with sudden palpitations and difficulty breathing, and her ECG reveals tachycardia. Which cardiac component typically experiences the most rapid depolarization?
Your Answer:
Correct Answer: Sino-atrial node
Explanation:The heart’s conducting system is made up of specialized cardiac muscle cells and fibers that generate and rapidly transmit action potentials. This system is crucial for coordinating the contractions of the heart’s chambers during the cardiac cycle. When this system malfunctions due to conduction blockages or abnormal action potential sources, it can lead to arrhythmias.
The conducting system has five main components:
1. The sino-atrial (SAN) node, located in the right atrium, generates electrical signals.
2. These signals stimulate the atria to contract and travel to the atrio-ventricular (AVN) node in the interatrial septum.
3. After a delay, the stimulus diverges and is conducted through the left and right bundle of His.
4. The conduction then passes to the respective Purkinje fibers for each side of the heart.
5. Finally, the electrical signals reach the endocardium at the apex of the heart and the ventricular epicardium.Understanding the Cardiac Action Potential and Conduction Velocity
The cardiac action potential is a series of electrical events that occur in the heart during each heartbeat. It is responsible for the contraction of the heart muscle and the pumping of blood throughout the body. The action potential is divided into five phases, each with a specific mechanism. The first phase is rapid depolarization, which is caused by the influx of sodium ions. The second phase is early repolarization, which is caused by the efflux of potassium ions. The third phase is the plateau phase, which is caused by the slow influx of calcium ions. The fourth phase is final repolarization, which is caused by the efflux of potassium ions. The final phase is the restoration of ionic concentrations, which is achieved by the Na+/K+ ATPase pump.
Conduction velocity is the speed at which the electrical signal travels through the heart. The speed varies depending on the location of the signal. Atrial conduction spreads along ordinary atrial myocardial fibers at a speed of 1 m/sec. AV node conduction is much slower, at 0.05 m/sec. Ventricular conduction is the fastest in the heart, achieved by the large diameter of the Purkinje fibers, which can achieve velocities of 2-4 m/sec. This allows for a rapid and coordinated contraction of the ventricles, which is essential for the proper functioning of the heart. Understanding the cardiac action potential and conduction velocity is crucial for diagnosing and treating heart conditions.
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This question is part of the following fields:
- Cardiovascular System
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Question 24
Incorrect
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Emergency medical services are summoned to attend to a 44-year-old motorcyclist who collided with a vehicle. The patient is alert but has sustained a fracture to the shaft of his right humerus. He is experiencing difficulty with extending his wrist and elbow. Which nerve is most likely to have been affected?
Your Answer:
Correct Answer: Radial
Explanation:The radial nerve is the most probable nerve to have been affected.
Understanding the anatomical pathway of the major nerves in the upper limb is crucial. The radial nerve originates from the axilla, travels down the arm through the radial groove of the humerus, and then moves anteriorly to the lateral epicondyle in the forearm. It primarily supplies motor innervation to the posterior compartments of the arm and forearm, which are responsible for extension.
The radial nerve is commonly damaged due to mid-humeral shaft fractures, shoulder dislocation, and lateral elbow injuries.
The Radial Nerve: Anatomy, Innervation, and Patterns of Damage
The radial nerve is a continuation of the posterior cord of the brachial plexus, with root values ranging from C5 to T1. It travels through the axilla, posterior to the axillary artery, and enters the arm between the brachial artery and the long head of triceps. From there, it spirals around the posterior surface of the humerus in the groove for the radial nerve before piercing the intermuscular septum and descending in front of the lateral epicondyle. At the lateral epicondyle, it divides into a superficial and deep terminal branch, with the deep branch crossing the supinator to become the posterior interosseous nerve.
The radial nerve innervates several muscles, including triceps, anconeus, brachioradialis, and extensor carpi radialis. The posterior interosseous branch innervates supinator, extensor carpi ulnaris, extensor digitorum, and other muscles. Denervation of these muscles can lead to weakness or paralysis, with effects ranging from minor effects on shoulder stability to loss of elbow extension and weakening of supination of prone hand and elbow flexion in mid prone position.
Damage to the radial nerve can result in wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals. Axillary damage can also cause paralysis of triceps. Understanding the anatomy, innervation, and patterns of damage of the radial nerve is important for diagnosing and treating conditions that affect this nerve.
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This question is part of the following fields:
- Neurological System
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Question 25
Incorrect
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A 32-year-old woman has a positive pregnancy test using a home kit that tests for the presence of a hormone in the urine.
Which structure secretes this hormone?Your Answer:
Correct Answer: Syncytiotrophoblast
Explanation:During the early stages of pregnancy, the corpus luteum is stimulated to secrete progesterone by hCG, which is produced by the syncytiotrophoblast. Pregnancy tests commonly measure hCG levels in urine. This hormone is crucial for maintaining the pregnancy until the placenta is fully developed. The trophoblast is composed of two layers: the cytotrophoblast and the syncytiotrophoblast. The hypoblast is a type of tissue that forms from the inner cell mass, while the epiblast gives rise to the three primary germ layers and extraembryonic mesoderm.
Endocrine Changes During Pregnancy
During pregnancy, there are several physiological changes that occur in the body, including endocrine changes. Progesterone, which is produced by the fallopian tubes during the first two weeks of pregnancy, stimulates the secretion of nutrients required by the zygote/blastocyst. At six weeks, the placenta takes over the production of progesterone, which inhibits uterine contractions by decreasing sensitivity to oxytocin and inhibiting the production of prostaglandins. Progesterone also stimulates the development of lobules and alveoli.
Oestrogen, specifically oestriol, is another major hormone produced during pregnancy. It stimulates the growth of the myometrium and the ductal system of the breasts. Prolactin, which increases during pregnancy, initiates and maintains milk secretion of the mammary gland. It is essential for the expression of the mammotropic effects of oestrogen and progesterone. However, oestrogen and progesterone directly antagonize the stimulating effects of prolactin on milk synthesis.
Human chorionic gonadotropin (hCG) is secreted by the syncitiotrophoblast and can be detected within nine days of pregnancy. It mimics LH, rescuing the corpus luteum from degenerating and ensuring early oestrogen and progesterone secretion. It also stimulates the production of relaxin and may inhibit contractions induced by oxytocin. Other hormones produced during pregnancy include relaxin, which suppresses myometrial contractions and relaxes the pelvic ligaments and pubic symphysis, and human placental lactogen (hPL), which has lactogenic actions and enhances protein metabolism while antagonizing insulin.
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This question is part of the following fields:
- Reproductive System
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Question 26
Incorrect
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What is the name of the protozoal infection that results in chronic diarrhoea, bloating, and weight loss, and is treated with metronidazole?
Your Answer:
Correct Answer: Giardia lamblia
Explanation:Protozoan Infections of the Gastrointestinal Tract
Giardiasis is a gastrointestinal condition caused by the ingestion of water contaminated with cysts of the protozoan Giardia lamblia. This protozoan can exist in two forms, an inactive cyst form used for transmission and an active trophozoite form. Once ingested, Giardia invades the duodenal enterocytes and resides there, occasionally shedding cysts into the stool. The symptoms of giardiasis can mimic many other gastrointestinal conditions, including Coeliac disease, and may only be diagnosed by biopsy during endoscopy. Treatment for giardiasis involves the use of metronidazole.
Cryptosporidium is another protozoan that can cause gastrointestinal symptoms, but only in immunocompromised individuals. Entamoeba histolytica, on the other hand, causes colitis with bloody diarrhoea and can lead to liver abscesses if it invades through to the portal vein. Treatment for Entamoeba histolytica involves the use of metronidazole and iodoquinol to clear colonisation in the liver.
Schistosoma species are not protozoa, but rather helminths that cause schistosomiasis. This condition can manifest in various ways, including intestinal, liver, and pulmonary symptoms.
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This question is part of the following fields:
- Microbiology
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Question 27
Incorrect
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A 16-year-old male presents to the emergency department after falling onto outstretched hands. An x-ray confirms a fracture in one of the bones in his forearm. Based on the mechanism of injury, which bone is most likely affected by this fracture?
Your Answer:
Correct Answer: Distal shaft of the radius
Explanation:The forearm has two weight-bearing bones, the scaphoid at the wrist and the radius within the forearm. If someone falls onto outstretched hands, there is a risk of fracturing both of these bones. The shaft of the radius is particularly vulnerable as it carries the weight and takes the full compression of the fall. The ulna is more likely to fracture from stress applied to the side of the arm rather than down its length. The lunate bone at the wrist is not involved in weight-bearing.
Anatomy of the Radius Bone
The radius bone is one of the two long bones in the forearm that extends from the lateral side of the elbow to the thumb side of the wrist. It has two expanded ends, with the distal end being the larger one. The upper end of the radius bone has articular cartilage that covers the medial to lateral side and articulates with the radial notch of the ulna by the annular ligament. The biceps brachii muscle attaches to the tuberosity of the upper end.
The shaft of the radius bone has several muscle attachments. The upper third of the body has the supinator, flexor digitorum superficialis, and flexor pollicis longus muscles. The middle third of the body has the pronator teres muscle, while the lower quarter of the body has the pronator quadratus muscle and the tendon of supinator longus.
The lower end of the radius bone is quadrilateral in shape. The anterior surface is covered by the capsule of the wrist joint, while the medial surface has the head of the ulna. The lateral surface ends in the styloid process, and the posterior surface has three grooves that contain the tendons of extensor carpi radialis longus and brevis, extensor pollicis longus, and extensor indicis. Understanding the anatomy of the radius bone is crucial in diagnosing and treating injuries and conditions that affect this bone.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 28
Incorrect
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A 29-year-old woman, who was recently diagnosed with iron deficiency anaemia secondary to menorrhagia, visits the clinic complaining of persistent fatigue and exhaustion despite being prescribed iron supplements. She has a medical history of dyspepsia that is managed with omeprazole.
What is the reason for the doctor's instruction to discontinue omeprazole?Your Answer:
Correct Answer: Omeprazole inhibits acid secretion which is essential for iron absorption
Explanation:Iron absorption is dependent on the presence of gastric acid, which can be hindered by the use of PPIs that reduce acid production. PPIs do not have a direct impact on iron metabolism or binding, but their inhibition of acid secretion can interfere with iron absorption. While ranitidine works by blocking histamine-2 receptors to reduce acid secretion, omeprazole is a proton pump inhibitor that operates differently.
Iron Metabolism: Absorption, Distribution, Transport, Storage, and Excretion
Iron is an essential mineral that plays a crucial role in various physiological processes. The absorption of iron occurs mainly in the upper small intestine, particularly the duodenum. Only about 10% of dietary iron is absorbed, and ferrous iron (Fe2+) is much better absorbed than ferric iron (Fe3+). The absorption of iron is regulated according to the body’s need and can be increased by vitamin C and gastric acid. However, it can be decreased by proton pump inhibitors, tetracycline, gastric achlorhydria, and tannin found in tea.
The total body iron is approximately 4g, with 70% of it being present in hemoglobin, 25% in ferritin and haemosiderin, 4% in myoglobin, and 0.1% in plasma iron. Iron is transported in the plasma as Fe3+ bound to transferrin. It is stored in tissues as ferritin, and the lost iron is excreted via the intestinal tract following desquamation.
In summary, iron metabolism involves the absorption, distribution, transport, storage, and excretion of iron in the body. Understanding these processes is crucial in maintaining iron homeostasis and preventing iron-related disorders.
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This question is part of the following fields:
- General Principles
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Question 29
Incorrect
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You are giving a lecture to a group of high school students on the pathophysiology of pemphigus vulgaris.
Halfway through your talk, you briefly mention the importance of cadherins, transmembrane proteins that are crucial for cell-cell adhesion, and explain that they rely on certain ions to function properly.
What specific ions are you referring to?Your Answer:
Correct Answer: Calcium ions
Explanation:Cadherins require calcium ions for their proper functioning.
Understanding Cadherins: Proteins that Play a Vital Role in Cell Adhesion
Cadherins are a type of transmembrane proteins that are crucial for cell adhesion. They are also known as ‘calcium-dependent adhesion’ proteins. These proteins are responsible for maintaining the integrity of tissues and organs by binding cells together. Cadherins are found in various tissues and organs, including epithelial tissues and neurons.
One of the most well-known cadherins is E-cadherin, which is found in epithelial tissues. Dysfunction of E-cadherin is often associated with tumour metastasis. Another type of cadherin is N-cadherin, which is found in neurons. It plays a crucial role in the development and maintenance of the nervous system. Desmoglein is another type of cadherin that is found in desmosomes, which are structures that hold cells together in tissues such as the skin. Pemphigus vulgaris is a disease that is caused by the formation of antibodies against desmoglein 3.
In summary, cadherins are essential proteins that play a vital role in cell adhesion. They are found in various tissues and organs and are responsible for maintaining the integrity of tissues and organs by binding cells together. Dysfunction of cadherins can lead to various diseases, including cancer and autoimmune disorders.
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This question is part of the following fields:
- General Principles
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Question 30
Incorrect
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A 15-year-old boy presents with diplopia and headache. Imaging reveals acute hydrocephalus and a space occupying lesion in the base of the 4th ventricle. What type of cell proliferation would be expected on biopsy?
Your Answer:
Correct Answer: Ependymal cells
Explanation:Childhood tumours of the central nervous system (CNS) frequently develop at the base of the 4th ventricle. Oligodendrocytes are accountable for creating the myelin sheath in the CNS. The formation of the blood-brain barrier is a crucial function of astrocytes. Schwann cells are responsible for creating the myelin sheath in the peripheral nervous system.
The nervous system is composed of various types of cells, each with their own unique functions. Oligodendroglia cells are responsible for producing myelin in the central nervous system (CNS) and are affected in multiple sclerosis. Schwann cells, on the other hand, produce myelin in the peripheral nervous system (PNS) and are affected in Guillain-Barre syndrome. Astrocytes provide physical support, remove excess potassium ions, help form the blood-brain barrier, and aid in physical repair. Microglia are specialised CNS phagocytes, while ependymal cells provide the inner lining of the ventricles.
In summary, the nervous system is made up of different types of cells, each with their own specific roles. Oligodendroglia and Schwann cells produce myelin in the CNS and PNS, respectively, and are affected in certain diseases. Astrocytes provide physical support and aid in repair, while microglia are specialised phagocytes in the CNS. Ependymal cells line the ventricles. Understanding the functions of these cells is crucial in understanding the complex workings of the nervous system.
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This question is part of the following fields:
- Neurological System
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