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Question 1
Correct
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Multiple cells were labelled using a fluorescent dye that doesn’t cross the cell membrane. One cell in the middle was bleached with a light that destroys the dye, but the cell soon recovers its stain. The presence of which structures best explains this?
Your Answer: Gap junctions
Explanation:Gap junctions are attachments between cells that permit intercellular communication e.g. they permit current flow and electrical coupling between myocardial cells. They allow direct electrical transmission among cells and also permit certain substance to pass through as well. They are either homotypic, formed by two identical hemichannels or heterotypic, formed by different hemichannels.
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This question is part of the following fields:
- General
- Physiology
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Question 2
Correct
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Blood supply to the posterior compartment of the thigh is supplied by which artery?
Your Answer: Perforating
Explanation:There are usually 3 perforating arteries:
The first gives branches to the adductor brevis and magnus, biceps femoris and gluteus maximus and anastomoses with the inferior gluteal, medial and lateral femoral circumflex.
The second artery supplies the posterior femoral muscles and anastomose with the first and third perforating vessels.
The third supplies the posterior femoral muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 3
Correct
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Purkinje fibres in the heart conduct action potentials at the rate of:
Your Answer: 1.5–4.0 m/s
Explanation:Purkinje fibres control the heart rate along with the sinoatrial node (SA node) and the atrioventricular node (AV node). The QRS complex is associated with the impulse passing through the Purkinje fibres. These fibres conduct action potential about six times faster than the velocity in normal cardiac muscle.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 4
Correct
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Which among the following vertebrae marks the lowest extent of the superior mediastinum?
Your Answer: Fourth thoracic
Explanation:The superior mediastinum lies between the manubrium anteriorly and the upper vertebrae of the thorax posteriorly. Below, it is bound by a slightly oblique plane that passes backward from the sternal angle to the lower part of the body of T4 and laterally by the pleura.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 5
Correct
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Muscles and tendons in the planter region of the foot mainly take blood supply from:
Your Answer: Posterior tibial artery
Explanation:The posterior tibial artery is the main source of blood supply to the posterior compartment of the leg.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 6
Correct
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A ‘claw hand’ is usually associated with injury to which of the following nerves?
Your Answer: Ulnar nerve
Explanation:A ‘claw hand’ is associated with injury to the ulnar nerve at the wrist affecting the interossei, lumbricals and hypothenar muscles of the hand. It is characterized by hypothenar eminence wasting, hyperextended metacarpophalangeal joints and flexed interphalangeal joints.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 7
Correct
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The chest X-ray of an 10-year-old boy, that presented with low-grade fever and cough, revealed hilar enlargement and parenchymal consolidation in the middle lobes. These X-ray findings are more typical for which of the following diagnoses?
Your Answer: Pulmonary tuberculosis
Explanation:Primary pulmonary tuberculosis is seen in patients exposed to Mycobacterium tuberculosis for the firs time. The main radiographic findings in primary pulmonary tuberculosis include homogeneous parenchymal consolidation typically in the lower and middle lobes, lymphadenopathy, miliary opacities and pleural effusion.
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This question is part of the following fields:
- Pathology
- Respiratory
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Question 8
Correct
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Which of these infectious agents tends to affect people under 20 and over 40 years old, can cause acute encephalitis with cerebral oedema and petechial haemorrhages, along with haemorrhagic lesions of the temporal lobe. A lumbar puncture will reveal clear cerebrospinal fluid with an elevated lymphocyte count?
Your Answer: Herpes simplex virus
Explanation:Haemorrhagic lesions of the temporal lobe are typical of Herpes simplex encephalitis (HSE). It tends to affect patients aged under 20 or over 40 years, and is often fatal if left untreated. In acute encephalitis, cerebral oedema and petechial haemorrhages occur and direct viral invasion of the brain usually damages neurones. The majority of cases of herpes encephalitis are caused by herpes simplex virus-1 (HSV-1), and about 10% of cases of herpes encephalitis are due to HSV-2, which is typically spread through sexual contact.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 9
Correct
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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: 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 10
Incorrect
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The gradual depolarization in-between action potentials in pacemaker tissue is a result of?
Your Answer: A gradual increase in inward Na+ (INa) channels current through fast Na+ channels
Correct Answer: A combination of gradual inactivation outward IK along with the presence of an inward ‘funny’ current (If) due to opening of channels permeable to both Na+ and K+ ions
Explanation:One of the characteristic features of the pacemaker cell is the generation of a gradual diastolic depolarization also called the pacemaker potential. In phase 0, the upstroke of the action potential caused by an increase in the Ca2+ conductance, an influx of calcium occurs and a positive membrane potential is generated. The next is phase 3 which is repolarization caused by increased K+ conductance as a result of outwards K+ current. Phase 4 is a slow depolarization which accounts for the pacemaker activity, caused by increased conductance of Na+, inwards Na+ current called IF. it is turned on by repolarization.
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This question is part of the following fields:
- General
- Physiology
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Question 11
Correct
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What is the chief ligament preventing posterior sliding of the tibia on the femur ?
Your Answer: Posterior cruciate
Explanation:The posterior cruciate ligament is attached to the posterior intercondyloid fossa of the tibia and the lateral and front part of the medial condyle of the femur. It resists sliding of the tibia posteriorly.
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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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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 13
Correct
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A chest x ray is ordered for a 39 year old man who presents with a history of a cough and weight loss for over a month. It shows a rounded opacity in the pleural cavity near the cardiac notch. The opacity is most likely to be in the:
Your Answer: Costomediastinal recess
Explanation:The costomediastinal recess is the point where the costal pleura becomes the mediastinal pleura, located right next to the cardiac notch.
The cupola: part of the parietal pleura that extends above the first rib to the root of the lung.
Hilum: located on the medial surface of the lung where neurovascular structures enter and leave the lung.
Pulmonary ligament: pleural fold found below the root of the lung, is a point of continuity between the visceral and mediastinal pleura.
Costodiaphragmatic recess: the lowest extent of the pleural cavity.
Superior mediastinum: part of the mediastinum that contains the great vessels leaving and entering the heart.
The cardiac notch is in the inferior mediastinum.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 14
Incorrect
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Which of the following is a large artery that runs immediately posterior to the stomach?
Your Answer: Left gastroepiploic
Correct Answer: Splenic
Explanation:The splenic artery is the large artery that would be found running off the posterior wall of the stomach. It is a branch of the coeliac trunk and sends off branches to the pancreas before reaching the spleen. The gastroduodenal artery on the other hand is found inferior to the stomach, posterior to the first portion of the duodenum. The left gastroepiploic artery runs from the left to the right of the greater curvature of the stomach. The common hepatic artery runs on the superior aspect of the lesser curvature of the stomach, and is a branch of the coeliac trunk. The superior mesenteric artery arises from the abdominal aorta just below the junction of the coeliac trunk.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 15
Incorrect
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The lateral thoracic artery:
Your Answer: Emerges through the triangular space
Correct Answer: Accompanies the long thoracic nerve to the serratus anterior muscle
Explanation:The thoracic nerve, along with the lateral thoracic artery, follow the pectoralis minor to the side of the chest which supplies the serratus anterior and the pectoralis. It then sends branches across the axilla to the axillary glands and subscapularis. The pectoral branch of the thoraco-acromial anastomoses with the internal mammary, subscapular and intercostal arteries, which in women, supply an external mammary branch.
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This question is part of the following fields:
- Anatomy
- Breast
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Question 16
Incorrect
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Which muscles are attached to the tibial tuberosity?
Your Answer: Pectineus
Correct Answer: Vastus intermedius
Explanation:The tuberosity of the tibia is the site of attachment to the ligamentum patella (the tendon of the quadriceps femoris muscle which include four heads: rectus femoris, vastus medialis, intermedius and lateralis).
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 17
Correct
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Carbachol is a cholinergic agonist. In which of these cases should carbachol be administered?
Your Answer: Cataract surgery
Explanation:Carbachol (carbamylcholine) is a cholinergic agent, a choline ester and a positively charged quaternary ammonium compound. It is primarily used for various ophthalmic purposes, such as for treating glaucoma, or for use during ophthalmic surgery. It is usually administered topically to the eye or through intraocular injection. It is not well absorbed in the gastro-intestinal tract and does not cross the blood–brain barrier.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 18
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 19
Correct
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What is the most likely condition a new born infant is likely to suffer from, if he/she was born with incomplete fusion of the embryonic endocardial cushions?
Your Answer: An atrioventricular septal defect
Explanation:The endocardial cushions in the heart are the mesenchymal tissue that make up the part of the atrioventricular valves, atrial septum and ventricular septum. An incomplete fusion of these mesenchymal cells can cause an atrioventricular septal defect. The terms endocardial cushion defect, atrioventricular septal defect and common atrioventricular canal defect can be used interchangeably with one another.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 20
Correct
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A 46-year old female patient experienced a stroke that affected her glossopharyngeal nerve. Damage to the glossopharyngeal nerve would most likely:
Your Answer: Result in general sensory deficit to the pharynx
Explanation:The glossopharyngeal nerve (CN IX) has many functions which include:
– Contributes to the pharyngeal plexus
– Receiving general somatic sensory fibres from the tonsils, pharynx, the middle ear and the posterior third of the tongue.
– supplies motor fibres to only one muscle; the stylopharyngeus muscle.
– provides parasympathetic fibres to the parotid gland via the otic ganglion.
– Receives visceral sensory fibres from the carotid bodies & carotid sinus.
– Receives special visceral sensory fibres from the posterior third of the tongue.
The above functions will directly be affected by the damage of the glossopharyngeal nerve.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 21
Correct
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After total thyroidectomy, which of the following investigations is recommended in the immediate post-operative period?
Your Answer: Serum calcium
Explanation:Total thyroidectomy might sometimes result in inadvertent excision or damage of parathyroid glands, leading to hypoparathyroidism. Monitoring serum calcium levels in the post-operative period to detect hypocalcaemia is essential to diagnose and prevent this condition.
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This question is part of the following fields:
- Endocrine
- Pathology
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Question 22
Correct
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A 34-year old gentleman presented with acute pancreatitis to the emergency department. On enquiry, there was found to be a history of recurrent pancreatitis, eruptive xanthomas and raised plasma triglyceride levels associated with chylomicrons. Which of the following will be found deficient in this patient?
Your Answer: Lipoprotein lipase
Explanation:The clinical features mentioned here suggest the diagnosis of hypertriglyceridemia due to lipoprotein lipase (LPL) deficiency. LPL aids in hydrolysing the lipids in lipoproteins into free fatty acids and glycerol. Apo-CII acts as a co-factor. Deficiency of this enzyme leads to hypertriglyceridemia.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 23
Correct
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Which structure holds the duodenojejunal flexure in place?
Your Answer: Suspensory ligament (of Treitz)
Explanation:The duodenum is connected to the diaphragm by the suspensory ligament called the ligament of Treitz. It is a slip of skeletal muscle from the right crus of the diaphragm and a fibromuscular band of smooth muscle from the 3rd and 4th parts of the duodenum. It is an important landmark, used to divide the gastrointestinal tract into the upper and lower parts. Contraction of this ‘ligament’ leads to opening of the duodenojejunal flexure allowing the flow of chyme.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 24
Incorrect
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Which of these conditions is mithramycin used for?
Your Answer: Organ transplantation
Correct Answer: Hypercalcaemia of malignancy
Explanation:Mithramycin or Plicamycin is a tricyclic pentaglycosidic antibiotic derived from Streptomyces strains. It inhibits RNA and protein synthesis by adhering to DNA. It is used as a fluorescent dye and as an antineoplastic agent. It is also used to reduce hypercalcaemia, especially caused by malignancy. Plicamycin is currently used in multiple areas of research, including cancer cell apoptosis and as a metastasis inhibitor.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 25
Correct
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Question 26
Correct
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Which of the following toxins most likely results in continuous cAMP production, which pumps H2O, sodium, potassium, chloride and bicarbonate into the lumen of the small intestine and results in rapid dehydration?
Your Answer: Cholera toxin
Explanation:The cholera toxin (CTX or CT) is an oligomeric complex made up of six protein subunits: a single copy of the A subunit (part A), and five copies of the B subunit (part B), connected by a disulphide bond. The five B subunits form a five-membered ring that binds to GM1 gangliosides on the surface of the intestinal epithelium cells. The A1 portion of the A subunit is an enzyme that ADP-ribosylates G proteins, while the A2 chain fits into the central pore of the B subunit ring. Upon binding, the complex is taken into the cell via receptor-mediated endocytosis. Once inside the cell, the disulphide bond is reduced, and the A1 subunit is freed to bind with a human partner protein called ADP-ribosylation factor 6 (Arf6). Binding exposes its active site, allowing it to permanently ribosylate the Gs alpha subunit of the heterotrimeric G protein. This results in constitutive cAMP production, which in turn leads to secretion of H2O, Na+, K+, Cl−, and HCO3− into the lumen of the small intestine and rapid dehydration. The gene encoding the cholera toxin was introduced into V. cholerae by horizontal gene transfer.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 27
Incorrect
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A 24-year old patient diagnosed with a direct inguinal hernia was scheduled for surgery to have the hernia repaired. The hernia was discovered to be protruding through the Hesselbach's triangle (inguinal triangle). Which of the following blood vessels that is a branch of the external iliac artery forms the lateral border of this triangle?
Your Answer: Internal pudendal
Correct Answer: Inferior epigastric
Explanation:The inguinal triangle is formed by the following structures; inguinal ligament at the base; inferior epigastric vessels laterally and the lateral border of the rectus sheath medially. This triangle (also known as Hesselebach’s triangle) is where direct inguinal hernias protrude. The inferior epigastric artery is this the branch of the external iliac artery being referred to. All the other blood vessels are branches of the internal iliac artery.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 28
Correct
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An old man was diagnosed with squamous cell carcinoma with axillary lymph node metastasis. The doctor said he will excise the tumour and remove all axillary lymph nodes lateral to the edge of the pectoralis minor muscle. One of the following axillary lymph nodes won't be removed by this procedure. Which is it?
Your Answer: Apical
Explanation:The apical lymph node group won’t be removed which include 20 to 30 lymph nodes.
Axillary lymph nodes are grouped according to location. The lateral group, the anterior to pectoral group, the posterior or subscapular group, the central group, and the medial or apical group. The lateral, pectoral, and subscapular groups are found lateral to the pectoralis minor muscle. The central group is situated directly under that muscle. Thus, if all lymph nodes lateral to the medial edge of the pectoralis minor muscle are removed, all the above four groups will be removed. The apical group won’t be removed which is situated medial to the medial edge of the pectoralis minor muscle.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 29
Correct
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Cranial nerve XII, the hypoglossal nerve, innervates which one of the following muscles in the list?
Your Answer: Hyoglossus
Explanation:The cranial nerve XII, hypoglossal nerve, innervates all the intrinsic and extrinsic muscles of the tongue except the palatoglossus. The muscles of the tongue innervated by this nerve include the extrinsic muscles; hyoglossus, styloglossus, genioglossus and the intrinsic muscles; superior longitudinal, inferior longitudinal, vertical and transverse muscles. The salpingopharyngeus, palatoglossus and the palatopharyngeus muscles are innervated by the vagus nerve. The stylopharyngeus muscle is innervated by the glossopharyngeal nerve (CN IX). The mylohyoid muscle is innervated by the inferior alveolar nerve, a branch of the mandibular nerve. Finally, the geniohyoid muscle is innervated by the olfactory nerve (CN I) via the hypoglossal nerve.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 30
Incorrect
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A 23-year-old woman decides to donate a kidney through a kidney chain. Which of the following indices would be expected to be decreased in the donor after full recovery from the operation?
Your Answer: Plasma creatinine concentration
Correct Answer: Creatinine clearance
Explanation:Since medication to prevent rejection is so effective, donors do not need to be similar to their recipient. Most donated kidneys come from deceased donors; however, the utilisation of living donors is on the rise. Most problems encountered with live donation are associated with the donor. Firstly, there are the potentially harmful investigative procedures carried out in the assessment phase, the most hazardous being renal angiography, where there is cannulation of the artery and injection of a radio-opaque dye to determine the blood supply to the kidney. Secondly, there are the short-term risks of nephrectomy surgery. According to the literature, there is a mortality rate of between 1 in 1600 and 1 in 3000, but this is no more than is associated with any anaesthetic. In the initial postoperative period creatinine clearance may be decreased but this recovers fully over a few weeks to months. Long-term complications include prolonged wound pain.
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This question is part of the following fields:
- Physiology
- Renal
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Question 31
Incorrect
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Calculate the stroke volume in a patient admitted for coronary bypass surgery, with the following parameters pre-operatively:
Oxygen consumption = 300 ml/min
Arterial oxygen content = 20 ml/100 ml blood
Pulmonary arterial oxygen content = 15 ml/100 ml blood and Heart rate = 100 beats/min.Your Answer: 10 ml
Correct Answer: 60 ml
Explanation:By Fick’s principle, cardiac output can be calculated as follows: VO2 = CO × (CAO2– CVO2) where VO2= oxygen consumption, CO = cardiac output, CAO2 = arterial oxygen content and CvO2 = mixed venous oxygen content. Thus, in the given problem, 300 ml/min = CO × (20 – 15) ml/100 ml CO = 300 × 100/5 ml/min CO = 6000 ml/min. Also, cardiac output = stroke volume × heart rate. Thus, 6000 ml/min = stroke volume × 100 beats/min. Hence, stroke volume = 6000/100 ml/min which is 60 ml/min.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 32
Correct
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A 7-year-old boys undergoes a testicular biopsy after a tumour is found in his right testis. Elements similar to hair and teeth are found in it. What kind of tumour is this?
Your Answer: Teratoma
Explanation:A teratoma is a tumour containing tissue elements that are similar to normal derivatives of more than one germ layer. They usually contain skin, hair, teeth and bone tissue and are more common in children, behaving as a benign tumour. After puberty, they are regarded as malignant and can metastasise.
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This question is part of the following fields:
- Pathology
- Urology
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Question 33
Correct
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A 7-year-old boy is diagnosed with metabolic acidosis as a result of severe dehydration. Which of the following conditions is most likely to cause severe dehydration and metabolic acidosis?
Your Answer: Severe diarrhoea
Explanation:Diarrhoea is defined as having three or more loose or liquid stools per day, or as having more stools than is normal for that person. Severe diarrhoea, causing fluid loss and loss of bicarbonate, will result in marked dehydration and metabolic acidosis.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 34
Correct
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Which of the following brings about a reduction in gastric blood flow?
Your Answer: Vasopressin
Explanation:Gastric blood flow is increased by vagal stimulation, gastrin, histamine and acetylcholine as they stimulate gastric section and the production of vasodilator metabolites. Acetylcholine and histamine also have a direct action on the gastric arterioles. Similarly, gastric blood flow is reduced by inhibitors of secretion – catecholamines, secretin and vasopressin.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 35
Correct
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Which of these antibiotics is the first choice treatment for infections caused by Pseudomonas aeruginosa?
Your Answer: Piperacillin
Explanation:Piperacillin is an extended-spectrum beta-lactam antibiotic of the ureidopenicillin class. It is normally used with a beta-lactamase inhibitor such as tazobactam. The combination has activity against many Gram-positive and Gram-negative pathogens and anaerobes, including Pseudomonas aeruginosa. Piperacillin is sometimes referred to as an anti-pseudomonal penicillin.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 36
Incorrect
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A 34-year-old man is receiving chemotherapy for non-Hodgkin's lymphoma. Which of the following chemotherapy regimens would be used in this case?
Your Answer: ABVD
Correct Answer: CHOP
Explanation:CHOP is the acronym for a chemotherapy regimen used in the treatment of non-Hodgkin’s lymphoma, comprising cyclophosphamide, hydroxyrubicin (adriamycin), vincristine and prednisone. This regimen can also be combined with the monoclonal antibody rituximab if the lymphoma is of B cell origin; this combination is called R-CHOP.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 37
Correct
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What class of drugs does buspirone belong to?
Your Answer: Anxiolytic
Explanation:Buspirone is an anxiolytic agent and a serotonin-receptor agonist that belongs to the azaspirodecanedione class of compounds. It shows no potential for addiction compared with other drugs commonly prescribed for anxiety, especially the benzodiazepines. The development of tolerance has not been noted. It is primarily used to treat generalized anxiety disorders. It is also commonly used to augment antidepressants in the treatment of major depressive disorder.
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This question is part of the following fields:
- Pathology
- Pharmacology
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Question 38
Correct
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A 70-year-old man who was previously healthy develops a rapidly progressing neurological deficit. A MRI reveals a large, poorly defined mass with central necrosis in his left temporal lobe. What is the most likely diagnosis?
Your Answer: Glioblastoma multiforme
Explanation:Glioblastoma multiforme, or grade 4 astrocytoma, is the most common and aggressive primary brain tumour. They are formed by small areas of necrotising tissue surrounded by highly anaplastic cells. Most of them arise from the deep white matter of the brain and quickly infiltrate it, becoming very large before they are symptomatic. The most common symptom is progressive memory, personality or neurological deficit due to temporal and frontal lobe involvement. It is most common in men, and risk factors include: neurofibromatosis, tuberous sclerosis, Von Hippel-Lindau disease, Li-Fraumeni syndrome, and Turcot syndrome.
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This question is part of the following fields:
- Neurology
- Pathology
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Question 39
Correct
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A 65-year-old female is taking different medications for various medical conditions. Which medication would most likely predispose the patient to develop hyperkalaemia?
Your Answer: Spironolactone
Explanation:The most important potential side effect of spironolactone is hyperkalaemia (high potassium levels), which, in severe cases, can be life-threatening. Hyperkalaemia in these patients can present as a non anion-gap metabolic acidosis.Â
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 40
Incorrect
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A 24-year-old patient with recurrent episodes of deep vein thrombosis presents again to the clinic. Deficiency of which of the following blood proteins is the most probable cause of this episode?
Your Answer: Alpha-2-antiplasmin
Correct Answer: Antithrombin III
Explanation:Antithrombin III (ATIII) is a blood protein that acts by inhibiting blood coagulation by neutralizing the enzymatic activity of thrombin.
Antithrombin III deficiency is an autosomal dominant disorder that leads to an increased risk of venous and arterial thrombosis. Clinical manifestations typically appear in young adulthood.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 41
Correct
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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: 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 42
Correct
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Due to a plantarflexion–inversion ankle sprain, which is the first ligament to rupture?
Your Answer: Anterior talofibular ligament
Explanation:The anterior talofibular ligament passes from the anterior margin of the fibular malleolus. It is the most commonly injured ligament, as part of the lateral ligament of the ankle.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 43
Correct
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A 38-year old lady presented to the hospital with abnormal passing of blood per vagina. On examination, she was found to have an endocervical polypoidal mass. On enquiry, she gave history of oral contraceptive usage for 3 years. What finding is expected on the histopathology report of biopsy of the mass?
Your Answer: Microglandular hyperplasia
Explanation:Endocervical polyps or microglandular hyperplasia are benign growths occurring in the endocervical canal, in about 2-5% women and occur secondary to use of oral contraceptives. They are usually < 1cm in size, friable and reddish-pink. Usually asymptomatic, they can cause bleeding or become infected, leading to leucorrhoea (purulent vaginal discharge). They are usually benign but need to be differentiated from adenocarcinomas by histology.
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This question is part of the following fields:
- Pathology
- Women's Health
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Question 44
Correct
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A surgeon ligates the left superior suprarenal artery whilst preforming a left adrenalectomy. Where does the left superior suprarenal artery originate?
Your Answer: Left inferior phrenic artery
Explanation:The superior suprarenal arteries arises from the inferior phrenic artery on either side.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 45
Correct
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If your EEG shows waves with a frequency range of 8-12 Hz, the waves most likely to be seen are:
Your Answer: Alpha
Explanation:Electroencephalography (EEG) is the neurophysiological measurement of the electrical activity of the brain. It is done by placing electrodes on the scalp or subdurally. In reality, the electrical currents are not measured, but rather the voltage differences between different parts of the brain. Four major types of EEG activity are recognized, which are alpha, beta, delta and theta.
Alpha waves, also known as Berger’s waves ranges in frequency from 8-12 Hz. Best detected with eyes closed, alpha waves are characteristic of a relaxed, alert state of consciousness. An alpha-like normal variant called mu is sometimes seen over the motor cortex (central scalp) and attenuates with movement or, rather, with the intention to move.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 46
Correct
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A 50-year-old gentleman was recently diagnosed with hypertension, with no other abnormalities on physical examination. Further investigations revealed the following :
Na+ 144 mmol/l
K+ 3.0 mmol/l
Cl- 107 mmol/l
Bicarbonate 25 mmol/l.
Blood glucose 5.8 mmol/l.
What is the likely diagnosis?Your Answer: Conn syndrome
Explanation:Overproduction of aldosterone (a mineralocorticoid) by the adrenal glands is known as Conn’s syndrome. It can be either due to an aldosterone-secreting adrenal adenoma (50-60% cases) or adrenal gland hyperplasia (40-50% cases). Excess aldosterone leads to sodium and water retention, along with potassium excretion. This leads to arterial (non-essential) hypertension. Conn’s syndrome is the commonest cause of primary hyperaldosteronism. Other symptoms include muscle cramps, headache (due to hypokalaemia) and metabolic alkalosis, which occurs due to increased secretion of H+ ions by the kidney. The raised pH of the blood traps calcium leading to symptoms of hypocalcaemia, which can be mimicked by liquorice ingestion and Liddle syndrome. To diagnose Conn’s syndrome, the ratio of renin and aldosterone is measured. Due to suppression of renin secretion, there is low renin to aldosterone ratio (<0.05). However, anti-hypertensives may affect the test results and should be withdrawn for 6 weeks. Computed tomography can also be done to detect the presence of adrenal adenoma. Cushing’s syndrome does not cause hypokalaemia with normal serum glucose levels. Nelson’s syndrome refers to increased ACTH secretion due to pituitary adenoma. Pheochromocytoma will not lead to hypokalaemia even though hypertension can be seen.
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This question is part of the following fields:
- Endocrine
- Pathology
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Question 47
Correct
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What is the arterial sequence for an analgesic to reach the latissimus dorsi muscle assuming that your starting point is at the subclavian vein?
Your Answer: Subclavian – axillary – subscapular – thoracodorsal
Explanation:Assuming our starting point is the subclavian artery, the analgesic continues in the same vessel into the axillary artery, as it passes into the axilla. The axillary artery at the lower border of the subscapularis gives rise to the subcapsular artery which is considered the largest branch of the axillary artery. This circumflex scapular branch distributes a serratus branch before entering the substance of the muscle as the thoracodorsal artery.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 48
Correct
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What is the result of maltase deficiency in the brush border of the small intestine?
Your Answer: Results in increased passage of maltose in stool
Explanation:Maltase is an enzyme produced from the surface cells of the villi, lining the small intestine and aids in hydrolysing the disaccharide maltose, which splits into two molecules of α-glucose. It is done by breaking the glycosidic bond between the ‘first’ carbon of one glucose and the ‘fourth’ carbon of the other (a 1–4 bond). Hence, a deficiency of enzyme maltase will result in the increased passage of maltose in the stool.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 49
Correct
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Where is factor VIII predominantly synthesised?
Your Answer: Vascular endothelium
Explanation:Factor VIII is an important part of the coagulation cascade. Deficiency causes haemophilia A. It is synthesised predominantly by the vascular endothelium and is not affected by liver disease. In the circulation it is bound to von Willebrand factor and it forms a stable complex with it. It is activated by thrombin or factor Xa and acts as a co factor to factor IXa to activate factor X which is a co factor to factor Va. Thrombin cleaves fibrinogen in fibrin and forms a meshwork to trap RBC and platelets to form a clot.
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This question is part of the following fields:
- General
- Physiology
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Question 50
Incorrect
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Which of the following can occur even in the absence of brainstem co-ordination?
Your Answer: Defecation
Correct Answer: Gastric emptying
Explanation:Although gastric emptying is under both neural and hormonal control, it does not require brainstem co-ordination. Increased motility of the orad stomach (decreased distensibility) or of the distal stomach (increased peristalsis), decreased pyloric tone, decreased duodenal motility or a combination of these, all increase the rate of gastric emptying. The major control mechanism for gastric emptying is through duodenal gastric feedback. The duodenum has receptors for the presence of acid, carbohydrate, fat and protein digestion products, osmolarity different from that of plasma, and distension. Activating these receptors decreases the rate of gastric emptying. Neural mechanisms involve both enteric and vagal pathways and a vagotomy impairs the gastric emptying regulation. CCK (cholecystokinin) slows gastric emptying at physiological levels of the hormone. Gastrin, secretin and glucose-1-phosphate also slow gastric emptying, but require higher doses.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 51
Incorrect
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During cardiac catheterisation in a 20-year old man, the following data is obtained: Pressure (mmHg), O2 saturation (%) Right atrium 7 (N = 5) 90 (N = 75), Right ventricle 35/7 (N = 25/5) 90 (N = 75), Pulmonary artery 35/8 (N = 25/15), 90 (N = 75), Left atrium 7 (N = 9) 95 (N = 95), Left ventricle 110/7 (N = 110/9) 95 (N = 95), Aorta 110/75 (N = 110/75) 95 (N = 95) where N = Normal value. What is the likely diagnosis?
Your Answer: Tricuspid insufficiency
Correct Answer: Atrial septal defect
Explanation:A congenital heart disease, ASD or atrial septal defect leads to a communication between the right and left atria due to a defect in the interatrial septum. This leads to mixing of arterial and venous blood from the right and left side of the heart. The hemodynamic significance of this defect depends on the presence of shunting of blood. Normally, the left side of the heart has higher pressure than the right as the left side has to pump blood throughout the body. A large ASD (> 9 mm) will result in a clinically significant left-to-right shunt, causing volume overload of the right atrium and ventricle, eventually leading to heart failure. Cardiac catheterization would reveal very high oxygen saturation in the right atrium, right ventricle and pulmonary artery. Eventually, the left-to-right shunt will lead to pulmonary hypertension and increased afterload in the right ventricle, along with the increased preload due to the shunted blood. This will either cause right ventricular failure, or raise the pressure in the right side of the heart to equal or more than that in the left. Elevation of right atrial pressure to that of left atrial pressure would thus lead to diminishing or complete cessation of the shunt. If left uncorrected, there will be reversal of the shunt, known as Eisenmenger syndrome, resulting in clinical signs of cyanosis as the oxygen-poor blood form right side of the heart will mix with the blood in left side and reach the peripheral vascular system.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 52
Correct
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A 60-year-old female has sudden onset of high-grade fever associated with cough with productive rusty-coloured sputum. Chest x-ray showed left-sided consolidation. What is the most accurate test for the diagnosis of this patient?
Your Answer: Sputum culture
Explanation:Sputum culture is used to detect and identify the organism that are infecting the lungs or breathing passages.
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 53
Correct
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A 20-year old cyclist falls off a speeding bike and fractures a structure that articulates with the tubercle of the 7th rib. Which structure is fractured?
Your Answer: Transverse process of vertebra T7
Explanation:A rib tubercle is a projection that is postero-inferior and lateral to the neck of a rib which articulates with the transverse process of the corresponding vertebra i.e. of the same number. Therefore, the tubercle of rib 7 articulates with the transverse process of T7 vertebra. The head of the rib 7, on the other hand, articulates with the 6th vertebra superiorly and the 7th vertebra inferiorly.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 54
Correct
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The fundus of the stomach receives blood supply from the same artery as the greater curvature of the stomach. Which of the following arteries when ligated will disrupt blood supply to the fundus of the stomach through this artery?
Your Answer: Splenic
Explanation:The fundus of the stomach along with the greater curvature of the stomach receive blood supply from the short gastric artery. The short gastric artery arises from the end of the splenic artery. The ligation of the splenic artery therefore would cause a disruption of blood supply to the fundus of the stomach.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 55
Correct
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The basilar artery arises from the confluence of which two arteries?
Your Answer: Vertebral
Explanation:The basilar artery is part of the vertebrobasilar system. It is formed by the confluence of the two vertebral arteries which arise from the subclavian arteries. These two vertebral arteries merge at the level of cranial nerve VI at the junction between the pons and the medulla oblangata to form what is know as the basilar artery. This vertebrobasilar system supplies the upper spinal cord, brainstem, cerebellum, and posterior part of brain.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 56
Correct
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In a young, sexually active male, what is the most common cause of non-gonococcal urethritis?
Your Answer: Chlamydia
Explanation:Non-gonococcal urethritis is most commonly caused by Chlamydia trachomatis (50% cases). Less common organisms include Mycoplasma genitalium, Urea urealyticum and Trichomonas vaginalis. Chlamydia is also the commonest cause of non-gonococcal cervicitis in women and proctitis in both sexes.
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This question is part of the following fields:
- Pathology
- Renal
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Question 57
Correct
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Which of the following structures is not easily palpable?
Your Answer: Styloid process of the temporal bone
Explanation:The styloid process is a thin, pointed process that projects antero-inferiorly from the base of the petrous temporal bone. It can vary in length from a short, stubby process to a slender, four to five centimetre rod. It forms from the cranial elements of the second pharyngeal arch. The tympanic plate of the temporal bone ensheathes the base of this process. The pointed, projecting portion of the process provides attachment to the stylohyoid and stylomandibular ligaments, and to three muscles – the styloglossus, stylohyoid, and stylopharyngeus. As the styloid process is covered by the various muscles, it is not easily palpable in live subjects.
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This question is part of the following fields:
- Anatomy
- Head & Neck
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Question 58
Correct
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A 27-year-old HIV patient started on an antifungal agent. Which antifungal agent that inhibits the biosynthesis of fungal ergosterol was given to the patient?
Your Answer: Ketoconazole
Explanation:Ketoconazole is a synthetic imidazole antifungal drug used primarily to treat fungal infections. It inhibits the biosynthesis of ergosterol by blocking demethylation at the C14 site of the ergosterol precursor. Amphotericin B and Nystatin impair permeability of the cell membrane. Flucytosine interferes with DNA synthesis, while the target of griseofulvin is the microtubules
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This question is part of the following fields:
- Microbiology
- Pathology
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Question 59
Incorrect
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A 44-year old man, who was euthyroid underwent thyroidectomy following neoplastic cells found on fine-needle aspiration. Frozen section of multiple thyroid masses showed malignant neoplasm of polygonal cells in nests. The neoplasm also showed presence of amyloid which was positive with Congo-red staining. Immunoperoxidase staining for calcitonin was also positive. Chest X-ray revealed no abnormality. However, his blood pressure was found to be raised, and his serum ionised calcium was high. What is the likely diagnosis?
Your Answer: Multiple endocrine neoplasia type I
Correct Answer: Multiple endocrine neoplasia type IIA
Explanation:MEN (Multiple Endocrine Neoplasia) syndromes are a group of three separate familial disease which consists of adenomatous hyperplasia and neoplasia in several endocrine glands. All three conditions are inherited as an autosomal dominant trait, with a single gene producing multiple effects. MEN IIA is characterized by medullary carcinoma of the thyroid, pheochromocytoma and hyperparathyroidism. It should be suspected in patients with bilateral pheochromocytoma, a familial history of MEN, or at least two characteristic endocrine manifestations. Genetic testing is used to confirm the diagnosis. Early diagnosis is crucial to aid in complete excision of the localized tumour. Pheochromocytomas can be detected by plasma free metanephrines and fractionated urinary catecholamines, particularly adrenaline (epinephrine).
Imaging studies such as computed tomography or magnetic resonance imaging might also prove useful. Hyperparathyroidism is diagnosed by the standard finding of hypercalcaemia, hypophosphatemia and an increased parathyroid hormone level. Once MEN IIA syndrome is identified in any patient, it is recommended that his or her first-degree relatives and any other symptomatic also undergo genetic testing. Relatives should be subjected to annual screening for hyperparathyroidism and pheochromocytoma beginning in early childhood and continue indefinitely. Serum calcium levels help in screening for hyperparathyroidism. Similarly, screening for pheochromocytoma is by history, measurement of the blood pressure and laboratory testing.
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This question is part of the following fields:
- Endocrine
- Pathology
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Question 60
Incorrect
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Work of breathing (WOB) is the energy expended to inhale and exhale a breathing gas. Normally, maximal amount of work of breathing is required to overcome:
Your Answer: Inertia
Correct Answer: Elastic lung compliance
Explanation:The forces of elastance (compliance), frictional resistance and inertia have been identified as the forces that oppose lung inflation and deflation. The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. About 60–66% of the total work performed by the respiratory muscles is used to overcome the elastic or compliance characteristics of the lung–chest cage, 30–35% is used to overcome frictional resistance and only 2–5% of the work is used for inertia.
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This question is part of the following fields:
- Physiology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
