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Question 1
Correct
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During routine laboratory tests, a 66-year-old man is found to be suffering from hypercholesterolaemia and is prescribed atorvastatin. What is the mechanism of action of atorvastatin?
Your Answer: Inhibits cholesterol synthesis
Explanation:Atorvastatin is a member of the drug class of statins, used for lowering cholesterol. The mode of action of statins is inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. This enzyme is needed by the body to make cholesterol. The primary uses of atorvastatin is for the treatment of dyslipidaemia and the prevention of cardiovascular disease.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 2
Correct
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An organ transplant patient may be at risk of developing which type of cancer?
Your Answer: Skin cancer
Explanation:The most common malignancies encountered in the post–solid organ transplant setting are non-melanoma skin cancers, post-transplant lymphoproliferative disorders and Kaposi’s sarcoma (KS). The pathogenesis of these tumours is likely related to the immunosuppressive drugs used post-transplantation and subsequent viral infection.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 3
Correct
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In order to arrest sudden bleeding during pericardiectomy that started after accidental injury to a major vasculature in the pericardium; the surgeon inserted his left index finger through the transverse pericardial sinus, pulled forward on the two large vessels lying ventral to his finger, and compressed these vessels with his thumb to control the bleeding. Which vessels were these?
Your Answer: Pulmonary trunk and aorta
Explanation:Transverse pericardial sinus: located behind two great vessels (aorta and pulmonary trunk) and in front of the superior vena cava and is accessed from above as in this case. The brachiocephalic trunk is located above the pericardium and the right pulmonary artery is above the pericardial reflections.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 4
Correct
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A 5 year-old-child with fever complains of sore throat . She was brought to her paediatrician for consult because she has also developed a rash and has swollen lymph nodes. Upon physical examination she cried when her liver was palpated and the tip of her spleen is slightly palpable. Full blood count shows haemoglobin 13 g/dL, Haematocrit 40%, white blood cell count 13x109/L with a WBC differential count of 45 neutrophils, 4 bands, 26 lymphocytes, 15 atypical lymphocytesm, 10 monocytes and 1 eosinophil. Whick is the most likely infectious agent that is responsible for the patient's condition?
Your Answer: Epstein–Barr virus
Explanation:Epstein-Barr virus (EBV), also known as human herpes virus 4,is a member of the herpes virus family. EBV spreads most commonly through bodily fluids, primarily saliva. EBV can cause infectious mononucleosis. Symptoms of EBV can include fatigue, fever, inflamed throat, swollen lymph nodes in the neck, enlarged spleen, swollen liver and rash.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 5
Incorrect
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An abdominal aortogram of a 59 year-old female with an abdominal aortic aneurysm shows occlusion of the inferior mesenteric artery. The patient, however, does not complain of any symptoms. Occlusion of the inferior mesenteric artery is rarely symptomatic because its territory is supplied by branches of the:
Your Answer: Ileocolic artery
Correct Answer: Middle colic artery
Explanation:The transverse colon is supplied by the middle colic artery which is a branch from the superior mesenteric artery. If the inferior mesenteric artery was occluded, branches from the middle colic may go to the marginal artery which supplies the descending colon, sigmoid colon and rectum.. Ileocolic and right colic arteries also branch from the superior mesenteric artery that supply the colon but the middle colic, which serves the more distal part of the colon is the better answer. The gastroduodenal artery branches off the common hepatic artery, which supplies part of the duodenum, pancreas and stomach. The splenic artery supplies the spleen, pancreas and curvature of the stomach.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 6
Correct
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A 55-year old gentleman presented to the doctor with worsening dysphagia for both solids and liquids over 6 months. This was associated with regurgitation of undigested food and occasional chest pain. Barium swallow revealed distal oesophageal dilatation with lack of peristalsis in the distal two-third oesophagus. The likely diagnosis is:
Your Answer: Achalasia
Explanation:Achalasia is an oesophageal motility disorder where inappropriate contractions in the oesophagus lead to reduced peristalsis and failure of the lower oesophageal sphincter to relax properly in response to swallowing. Classical triad of symptoms include dysphagia to fluids followed by solids, chest pain and regurgitation of undigested food. Other symptoms include belching, hiccups, weight loss and cough. Diagnosis is by:
– X-ray with a barium swallow or oesophagography : narrowing at the gastroesophageal junction (‘bird/parrot beak’ or ‘rat tail’ appearance) and various degrees of mega-oesophagus (oesophageal dilatation) as the oesophagus is gradually stretched by retained food. Effectiveness of treatment can be measured with a 5-minute timed barium swallow.
– Manometry – probe measures the pressure waves in different parts of oesophagus and stomach while swallowing.
– Endoscopy
– CT scan to exclude other causes like malignancy
– Pathological examination showing defect in the nerves which control oesophageal motility (myenteric plexus).
In Chagas disease, there is destruction of ganglion cells by Trypanosoma cruzi.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 7
Incorrect
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Low molecular weight heparin (LMWH) has less side effects than heparin and is used in the prophylaxis and treatment of venous and arterial thrombotic disorders. Which of the following is LMWHs mechanism of action?
Your Answer: Inhibition of antithrombin III
Correct Answer: Inhibition of factor Xa
Explanation:Low molecular weight heparin (LMWH) is a anticoagulant that differs from normal heparin in that it has only short chains of polysaccharide. LMWH inhibits thrombin formation by converting antithrombin from a slow to a rapid inactivator of coagulation factor Xa.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 8
Correct
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A woman that presented with dyspnoea, chest pain and cough was found to have a serous pleural effusion. This finding is most likely to be associated with which of the following conditions?
Your Answer: Congestive heart failure
Explanation:A pleural effusion is defined as an abnormal collection of fluid in the pleural space. Pleural effusion can result from excess fluid production or decreased absorption or both. Thoracentesis and laboratory testing help determine the origin of the accumulated fluid. Serous fluid accumulation in the pleural space indicates the presence of a hydrothorax and is most likely to develop secondary to congestive heart failure.
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This question is part of the following fields:
- Pathology
- Respiratory
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Question 9
Correct
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The thyrocervical trunk branches into which artery that passes upward and in front of the vertebral artery and longus colli muscle:
Your Answer: Inferior thyroid
Explanation:The inferior thyroid artery is an artery in the neck. It arises from the thyrocervical trunk and passes upward, in front of the vertebral artery and longus colli muscle.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 10
Correct
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Which of the following will be a likely sequelae of complete ileal resection?
Your Answer: Vitamin B12 deficiency
Explanation:The ileum is a part of the small intestine and has a pH of around 7-8 (neutral or slightly alkaline). Its main function is absorption of products of digestion. The ileal wall has multiple villi, which in turn have numerous microvilli. This increases the surface area available for absorption significantly. The cells lining the ileum contain multiple enzymes such as protease and carbohydrase, which aid in the final stages of digestion. Villi contain lacteals which absorb the products of fat digestion, fatty acids and glycerol. Thus, ileal resection will lead to their decreased absorption and increased fat content in the stool. The ileum is also responsible for absorption of vitamin B12.
Maximum water absorption occurs in the colon followed by the jejunum. Hence, ileal resection is less likely to lead to fluid volume deficiency. Also, most minerals (like calcium, iron etc.) are absorbed in the duodenum, and thus will not be affected by ileal resection.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 11
Correct
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Which is the correct superficial to deep order of structures that would be affected following a knife wound to the lateral aspect of the knee?
Your Answer: skin, fibular collateral ligament, popliteus muscle tendon, lateral meniscus
Explanation:Skin, fibular collateral ligament, popliteus muscle tendon and lateral meniscus is the correct order of structures covering the lateral aspect of the knee joint from a superficial to deep.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 12
Correct
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In a study, breast lumps were analysed to determine the characteristic of malignant neoplasm on biopsy. What microscopic findings are suggestive of malignancy?
Your Answer: Invasion
Explanation:Invasion is suggestive of malignancy and an even better option would have been metastasis. Pleomorphism is found in both benign and malignant neoplasms along with atypia and anaplasia. A height nuclear/cytoplasmic ratio is suggestive of malignancy but not the best indicator. Malignant tumours are aggressive and growth rapidly. Necrosis can be seen in benign tumours if they deplete their blood supply.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 13
Correct
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The Henderson–Hasselbalch equation describes the derivation of pH as a measure of acidity. According to this equation, the buffering capacity of the system is at maximum when the number of free anions compared with undissociated acid is:
Your Answer: Equal
Explanation:In 1908, Lawrence Joseph Henderson wrote an equation describing the use of carbonic acid as a buffer solution. Later, Karl Albert Hasselbalch re-expressed that formula in logarithmic terms, resulting in the Henderson–Hasselbalch equation. The equation is also useful for estimating the pH of a buffer solution and finding the equilibrium pH in acid–base reactions. Two equivalent forms of the equation are: pH = pKa + log10 [A–]/[HA] or pH = pKa + log10 [base]/[acid]. Here, pKa is − log10(Ka) where Ka is the acid dissociation constant, that is: pKa = –log10(Ka) = –log10 ([H3 O+][A–]/[HA]) for the reaction: HA + H2 O ≈ A– + H3 O+ In these equations, A– denotes the ionic form of the relevant acid. Bracketed quantities such as [base] and [acid] denote the molar concentration of the quantity enclosed. Maximum buffering capacity is found when pH = pKa or when the number of free anions to undissociated acid is equal and buffer range is considered to be at a pH = pKa ± 1.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 14
Incorrect
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Rapid eye movement (REM) sleep is likely to be affected by a lesion in the:
Your Answer: Frontal lobe
Correct Answer: Pons
Explanation:Rapid eye movement (REM) sleep is also known as paradoxical sleep, as the summed activity of the brain’s neurons is quite similar to that during waking hours. Characterised by rapid movements of the eyes, most of the vividly recalled dreams occur during this stage of sleep. The total time of REM sleep for an adult is about 90–120 min per night.
Certain neurones in the brainstem, known as REM sleep-on cells, which are located in the pontine tegmentum, are particularly active during REM sleep and are probably responsible for its occurrence. The eye movements associated with REM are generated by the pontine nucleus with projections to the superior colliculus and are associated with PGO (pons, geniculate, occipital) waves.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 15
Correct
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A 45-year old gentleman presented to the emergency department at 5.00 AM with pain in his left flank. The pain began suddenly and presented in waves throughout the night. Urine examination was normal except for presence of blood and few white blood cells. The pH and specific gravity of the urine were also found to be within normal range. What is the likely diagnosis?
Your Answer: Ureteric calculus
Explanation:A calculus in the ureter, if less than 5mm in diameter is likely to pass spontaneously. However, a larger calculus irritates the ureter and may become lodged, leading to hydroureter and/or hydronephrosis. Likely sites where the calculus might get lodged, include pelviureteric junction, distal ureter at the level of iliac vessels and the vesicoureteric junction. An obstruction can result in reduced glomerular filtration. There can be deterioration in renal function due to hydronephrosis and a raised glomerular pressure, leading to poor renal blood flow. Permanent renal dysfunction usually takes about 4 weeks to occur. Secondary infection can also occur in chronic obstruction.
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This question is part of the following fields:
- Pathology
- Renal
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Question 16
Incorrect
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A 25 year old male patient who had sustained a stab wound in the middle of the posterior aspect of the left thigh, was discharged from hospital after dressing and antibiotic prophylaxis. Later on the patient developed bleeding through the wound and upon review, the source was discovered to be an artery that is the direct source of the medial and lateral circumflex arteries. Which is this artery that was injured?
Your Answer: First perforating artery
Correct Answer: Profunda femoris artery
Explanation:The medial and lateral circumflex arteries are direct branches of the Profunda femoris artery otherwise also known as the deep artery of the thigh. The Profunda femoris artery arises from the femoral artery just below the inguinal ligament (approximately 2-5cm below it).
The following are the branches of the deep artery of the thigh:
Lateral circumflex femoral artery
Medial circumflex femoral artery
Perforating arteries
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 17
Incorrect
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A surgeon trainee is assisting in an operation to ligate the ductus arteriosus. The consultant supervising explains that caution is required when placing a clamp on the ductus to avoid injury to an important structure immediately dorsal to it. To which structure is the consultant referring?
Your Answer: Left internal thoracic artery
Correct Answer: Left recurrent laryngeal nerve
Explanation:The left recurrent laryngeal nerve branches off the vagus and wraps around the aorta, posterior to the ductus arteriosus/ligamentum arteriosum from whence it courses superiorly to innervate the laryngeal muscles.
Accessory Hemiazygous vein is on the left side of the body draining the posterolateral chest wall and emptying blood into the azygos vein.
The left internal thoracic artery is branch of the left subclavian artery supplying blood to the anterior wall of the thorax.
Left phrenic nerve is lateral to the vagus nerve.
Thoracic duct: is behind the oesophagus, coursing between the aorta and the azygos vein in the posterior chest.
Right recurrent laryngeal nerve: loops around the right subclavian artery and is not in danger in this procedure.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 18
Correct
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C5a (a complement component) is a potent?
Your Answer: Anaphylotoxin
Explanation:C5a is a strong chemoattractant as well as an anaphylotoxin and is involved in the recruitment of inflammatory cells such as neutrophils, eosinophils, monocytes, and T lymphocytes. It is also involved in activation of phagocytic cells, release of granule-based enzymes and generation of oxidants. All of which contribute to innate immune functions.
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This question is part of the following fields:
- General
- Physiology
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Question 19
Incorrect
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Multiple, non-tender lymphadenopathy with biopsy showing several crowded follicles of small, monomorphic lymphocytes and the absence of Reed-Sternberg cells is seen in which of the following?
Your Answer: Chronic lymphocytic leukaemia
Correct Answer: Poorly differentiated lymphocytic lymphoma
Explanation:Malignant lymphoma usually causes non-tender lymphadenopathy, unlike the tender lymphadenopathy caused by infections (including infectious mononucleosis caused by Epstein-Barr virus). Also, the lymphoid hyperplasia seen in infectious mononucleosis is benign and polyclonal.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 20
Incorrect
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A young man was thrown from a vehicle in a collision. He landed on his head and shoulder tip, stretching the left side of his neck. A neurological examination revealed that the fifth and sixth cervical nerves had been torn from the spinal cord. What is the most obvious clinical manifestation of this?
Your Answer: Medial rotation
Correct Answer: Abduction
Explanation:In the case of injuries to the upper roots of the brachial plexus there is complete loss of abduction. The muscle performing this movement is the supraspinatus. This initiates the movement, followed by the deltoid muscle, which allows for complete abduction. Both these muscles are innervated by nerves originating from C5 and C6. The injury to these roots results in a condition named Erb-Duchenne’s palsy.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 21
Incorrect
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A 7-year old child from a rural setting complains of recurrent abdominal pain. The child is found to have a heavy parasitic infestation and anaemia. Which type of anaemia is most likely seen in this patient?
Your Answer: Folic acid deficiency anaemia
Correct Answer: Iron deficiency anaemia
Explanation:The most common cause of iron deficiency anaemia in children in developing countries is parasitic infection (hookworm, amoebiasis, schistosomiasis and whipworm).
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 22
Incorrect
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A cell is classified on the basis of its regenerative ability. Which of the following cells represent a permanent cell?
Your Answer: Osteocyte
Correct Answer: Erythrocyte
Explanation:An erythrocyte is the last cell in the progeny of RBC cell division and is not capable of further division and regeneration. Hepatocytes, osteocytes and epithelium of kidney tubules are all stable cells. Colonic mucosa and pluripotent hematopoietic stem cells are all labile cells.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 23
Incorrect
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Acute respiratory distress syndrome (ARDS) is a medical condition that occurs in critically ill patients, and can be triggered by events such as trauma and sepsis. Which of the following variables is most likely to be lower than normal in a patient with ARDS?
Your Answer: Surface tension of alveolar fluid
Correct Answer: Lung compliance
Explanation:Acute (or Adult) respiratory distress syndrome (ARDS) is a medical condition occurring in critically ill patients characterized by widespread inflammation in the lungs. The development of acute respiratory distress syndrome (ARDS) starts with damage to the alveolar epithelium and vascular endothelium, resulting in increased permeability to plasma and inflammatory cells. These cells pass into the interstitium and alveolar space, resulting in pulmonary oedema. Damage to the surfactant-producing type II cells and the presence of protein-rich fluid in the alveolar space disrupt the production and function of pulmonary surfactant, leading to micro atelectasis and impaired gas exchange. The pathophysiological consequences of lung oedema in ARDS include a decrease in lung volumes, compliance and large intrapulmonary shunts. ARDS may be seen in the setting of pneumonia, sepsis, following trauma, multiple blood transfusions, severe burns, severe pancreatitis, near-drowning, drug reactions, or inhalation injuries.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 24
Correct
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A 53 year old women with a history of atrial fibrillation developed an acute abdomen. On laparoscopic examination her bowels appeared to be dusky to red-purple in colour and her mesenteric veins appeared to be patent. Which of the following is most likely to occur in this situation?
Your Answer: Wet gangrene
Explanation:Infarction of the small bowel following a sudden and complete occlusion of the mesenteric artery can involve any portion of the bowel, whether small or a large. The splenic flexure is at most risk for infarction as it is the watershed area between the superior and inferior mesenteric vessels. Regardless of whether the arterial or the venous blood vessels are occluded, because of the blood reflow into the damaged portion, it will appear haemorrhagic. The bowel appearing congested at first and then becoming oedematous. If the artery is occluded then there will be a clear cut demarcation and in venous occlusion the dusky colour fades with the rest of the normal bowel. Wet gangrene is characteristic of ischaemic injury to the gut.
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This question is part of the following fields:
- Cell Injury & Wound Healing; Gastrointestinal
- Pathology
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Question 25
Incorrect
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A 27 year-old male patient was admitted to the hospital due to recurrent fever for the past 2 weeks. The patient claimed that he is an intravenous drug user. Following work up, the patient was diagnosed with infective endocarditis. Which is the most likely organism responsible for this diagnosis?
Your Answer: Enterococcus
Correct Answer: Staphylococcus aureus
Explanation:Acute bacterial endocarditis is a fulminant illness lasting over days to weeks (<2weeks). It is most likely due to Staphylococcus aureus especially in intravenous drug abusers.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 26
Incorrect
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Which organs amongst these are the derivatives of the endoderm?
Your Answer: Adrenal medulla
Correct Answer: Epithelial part of the tympanic cavity
Explanation:Endoderm derivatives include the epithelium of the following: gastrointestinal tract and its glands, glandular cells of the liver and pancreases, urachus and urinary bladder, pharynx, trachea and alveoli, part of the tonsils, thyroid and parathyroid, tympanic cavity and thymus and part of the anterior pituitary gland.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 27
Incorrect
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A lad involved in a road traffic accident is rushed to casualty where physical examination reveals that he has limited extension of his right humerus. Which of the following nerves is most likely to have been injured?
Your Answer: Suprascapular nerve
Correct Answer: Thoracodorsal nerve
Explanation:Extension of the humerus is a function of the latissimus dorsi. This muscle is supplied by the thoracodorsal nerve which is a branch of the posterior cord of the plexus whose fibres are derived from cranial nerves V, VI and VII.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 28
Correct
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A neurotransmitter of the nigrostriatal pathway is:
Your Answer: Dopamine
Explanation:Dopamine acts as a neurotransmitter in the brain, activating dopamine receptors. It is also a neurohormone released from the hypothalamus. It plays an important role in the reward system. It is believed that dopamine provides a teaching signal to parts of the brain responsible for acquiring new motor sequences (behaviours), by activation of dopamine neurons when an unexpected reward is presented. Loss of dopamine neurones in the nigrostriatal pathway causes Parkinson’s disease. In the frontal lobes, dopamine controls the flow of information from other areas of the brain, and thus, dopamine disorders in this region can cause a decline in neurocognitive functions, especially memory, attention and problem solving. Reduced dopamine concentrations in the prefrontal cortex are thought to contribute to attention-deficit disorder and some symptoms of schizophrenia. Dopamine is also the primary neuroendocrine regulator of the secretion of prolactin from the anterior pituitary gland. Dopamine is also commonly associated with the pleasure system of the brain. This plays a key role in understanding the mechanism of action of drugs (such as cocaine and the amphetamines), which seem to be directly or indirectly related to the increase of dopamine.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 29
Correct
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Which of the following foramen provides passage of the facial nerve?
Your Answer: Internal acoustic meatus
Explanation:The internal auditory meatus provides a passage through which the vestibulocochlear nerve, the facial nerve, and the labyrinthine artery (an internal auditory branch of the basilar artery) can pass from inside the skull to structures of the inner ear and face.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 30
Correct
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The pterion is clinically significant as it marks an area of weakness on the skull. What structure lies beneath it?
Your Answer: Anterior branches of the middle meningeal artery
Explanation:The pterion is the area where four bones, the parietal, frontal, greater wing of sphenoid and the squamous part of the temporal bone meet. It overlies the anterior branch of the middle meningeal artery on the internal aspect of the skull. The pterion is the weakest part of the skull. Slight trauma to this region can cause extradural hematoma.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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SESSION STATS - PERFORMANCE PER SPECIALTY
