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Question 1
Correct
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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: 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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Question 2
Correct
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The pattern of drainage of the lymphatic and venous systems of the anterior abdominal wall is arranged around a horizontal plane above which drainage is in a cranial direction and below which drainage is in a caudal direction. Which horizontal plane is being referred to?
Your Answer: Level of the umbilicus
Explanation:The umbilicus is a key landmark for the lymphatic and venous drainage of the abdominal wall. Above it, lymphatics drain into the axillary lymph nodes and the venous blood drains into the superior epigastric vein, into the internal thoracic vein. Below it, lymphatics drain into the superficial inguinal lymph nodes while venous blood drains into the inferior epigastric vein and the external iliac vein.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 3
Correct
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A young boy fell from a tree, sustaining an injury to the elbow area and damaging the nerve behind the medial epicondyle of the humerus. What is the most likely result from that injury?
Your Answer: Flexion in the distal interphalangeal joint of digit 5
Explanation:The nerve injured in this situation is the ulnar nerve. It passes posterior to the medial epicondyle of the humerus before going between the two heads of the flexor carpi ulnaris muscle. This nerve supplies the muscles and skin of forearm and hand. At the level of medial epicondyle, the injury will led to paralysis in flexor carpi ulnaris and the ulnar half of the flexor digitorum profundus as well as the palmar interossei and hypothenar muscles in the hand. The correct answer will be that the boy will suffer from inability to flex the distal interphalangeal joint of digit 5
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 4
Correct
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A 31 -year-old female patient had a blood gas done on presentation to the emergency department. She was found to have a metabolic acidosis and decreased anion gap. The most likely cause of these findings in this patient would be?
Your Answer: Hypoalbuminemia
Explanation:A low anion gap might be caused by alterations in serum protein levels, primarily albumin (hypoalbuminemia), increased levels of calcium (hypercalcaemia) and magnesium (hypermagnesemia) or bromide and lithium intoxication. However, the commonest cause is hypoalbuminemia, thus if the albumin concentration falls, the anion gap will also be lower. The anion gap should be corrected upwards by 2.5 mmol/l for every 10g/l fall in the serum albumin.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 5
Incorrect
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The transmembrane proteins responsible for resting membrane potential of vascular smooth muscle cells was blocked by a drug. Which of the following transmembrane proteins were blocked by this drug?
Your Answer: Ca2+ channels
Correct Answer: K+ channels
Explanation:The resting membrane potential is due to selective permeability of the membrane to potassium ions. The Na/K pump is responsible for the generation of a gradient across the membrane and it is due to the inherent ability of the K channels to allow diffusion back into the nerve at rest which charges the cells. In reality, the resting membrane potential is more positive because of small contributions by Na+ channels, Cl− channels and non-selective cation channels.
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This question is part of the following fields:
- General
- Physiology
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Question 6
Incorrect
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During an operation to repair an aortic coarctation in a neonate, a surgeon accidentally cuts the first aortic intercostal arteries as he mobilised the descending aorta. Which one of the following structure might be deprived of its primary source of blood supply following this injury?
Your Answer: First anterior intercostal space
Correct Answer: Right bronchus
Explanation:The right bronchus is supplied by one right bronchial artery that may branch from one of the left bronchial arteries or from the right 3rd posterior intercostal artery (this is the first intercostal artery that arises from the aorta). Damage to this artery might stop blood supply to the main bronchus. Intercostal arteries that go to the first and the second interspaces originate from the highest intercostal artery such that blood supply to either of these spaces would not be interfered with.
The left bronchus receives blood from 2 left bronchial arteries which are direct branches from the descending aorta.
Fibrous pericardium is the sac that contains the heart. Its blood supply is not a major concern.
Visceral pericardium receives its blood supply from the coronary vessels.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 7
Correct
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Which of the following substances brings about a dilatation of the gastrointestinal resistance vessels?
Your Answer: Vasoactive intestinal peptide
Explanation:Gastric vasoconstrictors include catecholamines, angiotensin II and vasopressin. Vasodilators include vasoactive intestinal peptide and the hormones; gastrin, cholecystokinin and glucagon.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 8
Correct
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A 45 year-old male, with behavioural changes developed euvolemic hyponatraemia. Which of the following conditions most likely predisposed the patient to develop euvolemic hyponatraemia?
Your Answer: Psychosis
Explanation:In euvolemic hyponatraemia, there is volume expansion in the body, there is no oedema, but hyponatremia occurs. Causes include: state of severe pain or nausea, psychosis, brain trauma, SIADH, hypothyroidism and glucocorticoid deficiency.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 9
Incorrect
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What are some of the derivatives of the second pharyngeal arch?
Your Answer: Stylopharyngeus muscle
Correct Answer: Stylohyoid muscle
Explanation:Also known as the hyoid arch, it forms the side and front of the neck. From its cartilage develops the styloid process, stylohyoid ligament and lesser cornu of the hyoid bone. The muscular derivatives include the muscles of facial expression, stapedius, stylohyoid and the posterior belly of the digastric. All these are innervated by cranial nerve VII but migrate into the area of the mandibular arch.
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This question is part of the following fields:
- Anatomy
- Embryology
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Question 10
Correct
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A patient at the time of her second delivery opted for a bilateral pudendal nerve block. In order to inject the anaesthetic agent near the pudendal nerve a anaesthetic consultant had to insert a finger into the vagina and press laterally to palpate which landmark?
Your Answer: Ischial spine
Explanation:The ischial spine is always palpated through the walls of the vagina when performing a transvaginal pudendal nerve block and can easily be palpated on the lateral wall of the vagina.
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This question is part of the following fields:
- Anatomy
- Pelvis
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Question 11
Correct
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Following a bee sting, a women develops a 2cm red, raised, swollen lesion at the site of the sting . Which of the following findings is likely to be seen in this lesion?
Your Answer: Vasodilation
Explanation:Inflammation is the immediate response of the body towards infections or irritations. The cardinal signs of inflammation are 1. redness/rubor, 2. tumour/swelling, 3.dolar/pain, 4.calor/heat and organ dysfunction (function laesa). Inflammation has 2 components; vascular and cellular. Blood vessels dilate upstream of the inflamed area leading to the rubor and calor and constrict downstream, increasing pressure and causing fluid to leak out of the capillary, resulting in swelling. The cellular component includes infiltration by neutrophils. Leukocyte arrival and functions include; 1. margination: cells marginated from the centre to the periphery of the vessel, 2. rolling: selectins are upregulated on the vessel walls, 3. adhesion: upregulation of the adhesion molecules ICAM and VCAM on the endothelium interact with integrins on the leukocytes resulting in adhesion, 4. diapedesis and chemotaxis: diapedesis is the transmigration of the leukocyte across the endothelium of the capillary and towards a chemotactic product and 5. phagocytosis: engulfing the offending substance/cell.
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This question is part of the following fields:
- Inflammation & Immunology
- Pathology
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Question 12
Incorrect
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When a penile tumour invades the subepithelial connective tissue of the penis, what is its stage?
Your Answer: T2
Correct Answer: T1
Explanation:The TNM staging used for penile cancer is as follows:
TX: primary tumour cannot be assessed
T0: primary tumour is not evident
Tis: carcinoma in situ is present
Ta: non-invasive verrucous carcinoma is present
T1: tumour is invading subepithelial connective tissue
T2: tumour is invading the corpora spongiosum or cavernosum
T3: tumour invading the urethra or prostate
T4: tumour invading other adjacent structures.
In this case, the patient has a T1 tumour.
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This question is part of the following fields:
- Pathology
- Urology
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Question 13
Correct
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The mechanism of action of streptokinase involves:
Your Answer: Direct conversion of plasminogen to plasmin
Explanation:Streptokinase is an enzyme that is produced by group A beta haemolytic streptococcus and is an effective and cost efficient method for the dissolution of a clot used in cases of MI and pulmonary embolism. It works by directly converting plasminogen to plasmin which breaks down the blood components in the clot and fibrin, dissolving the clot. Streptokinase is a bacterial product and thus the body will develop immunity against it.
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This question is part of the following fields:
- General
- Physiology
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Question 14
Correct
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A patient with this type of tumour is advised to follow up regularly for monitoring of tumour size as there is a strong correlation with malignant potential and tumour size. Which of the following is the most likely tumour in this patient?
Your Answer: Renal adenocarcinoma
Explanation:The distinction between a benign renal adenoma and renal adenocarcinoma is commonly made on the basis of size. Tumours less than 2 cm in size rarely become malignant as opposed to those greater than 3 cm.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 15
Correct
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You observe a procedure to harvest the left internal thoracic (mammary) artery to be used as a graft for coronary artery bypass surgery. The left internal thoracic artery is mobilised from the inside of the chest wall and divided near the caudal end of the sternum. After dividing the internal thoracic artery at its distal end, the specialist registrar asks you to name the artery that will now have increased blood supply so that adequate blood flow is maintained to the rectus abdominis on the left side. What would your answer be?
Your Answer: Inferior epigastric artery
Explanation:The rectus abdominis muscle is supplied by the superior epigastric artery which is a branch of the internal thoracic artery. If the internal thoracic artery is thus ligated, blood would no longer flow to it. However, the superior epigastric artery communicates with the inferior epigastric artery (a branch of the external iliac artery). This means that blood could flow from the external iliac, to the inferior epigastric, to the superior epigastric to the rectus abdominis.
The superficial circumflex iliac artery and the superficial epigastric are two superficial branches of the femoral artery and do not supply the deep branches of the abdomen.
The deep circumflex iliac artery travels along the iliac crest on the inner surface of the abdominal wall; being too lateral it doesn’t supply blood to the rectus abdominis.
The distal portions of the umbilical arteries are obliterated in adults to form the medial umbilical folds.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 16
Correct
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A patient presented with continuous bleeding several hours after dental extraction. Which of the following findings is most often associated with clinical bleeding?
Your Answer: Factor IX deficiency
Explanation:Factor IX deficiency, also called Haemophilia B or Christmas disease, is a disorder caused by missing or defective clotting factor IX. Deficiency of the factor IX causes irregular bleeding that can happen spontaneously or after mild trauma, surgery and dental extractions.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 17
Incorrect
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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 apoprotein synthesis
Correct 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 18
Correct
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Which of the following is not seen as a complication of wound healing?
Your Answer: Malignancy
Explanation:Complications in wound healing can originate due to abnormalities in the repair process. These abnormalities are :
1) Deficient scar formation: insufficient granulation tissue can lead to wound dehiscence and ulceration. Dehiscence or wound rupture is seen most commonly in abdominal surgery due to increased intraabdominal pressure. Ulcerations are common in extremity wounds due to inadequate vascularization.
2) Excessive formation of repair components: collagen being laid down may begin normally however later lead to a raised scar also called a hypertrophic scar, which can extend beyond its boundaries to form a keloid and
3) Formation of contractures.
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This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
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Question 19
Correct
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Which part of the nephron would have to be damaged to stop the reabsorption of the majority of salt and water?
Your Answer: Proximal tubule
Explanation:The proximal tubule is the portion of the duct system of the nephron of the kidney which leads from Bowman’s capsule to the loop of Henle. It is conventionally divided into the proximal convoluted tubule (PCT) and the proximal straight tubule (PST). The proximal tubule reabsorbs the majority (about two-thirds) of filtered salt and water. This is done in an essentially iso-osmotic manner. Both the luminal salt concentration and the luminal osmolality remain constant (and equal to plasma values) along the entire length of the proximal tubule. Water and salt are reabsorbed proportionally because the water is dependent on and coupled with the active reabsorption of Na+. The water permeability of the proximal tubule is high and therefore a significant transepithelial osmotic gradient is not possible.
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This question is part of the following fields:
- Physiology
- Renal
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Question 20
Correct
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The specialist registrar, while performing the repair of an infrarenal abdominal aortic aneurysm, decides not to re-implant the inferior mesenteric artery into the repaired abdominal aorta. She says that an anastomotic artery running along the border of the large intestine is good enough to supply blood to the territory of the inferior mesenteric artery. Which vessel is she referring to?
Your Answer: Marginal
Explanation:The marginal artery is a key anastomosis for the large intestine that runs around the border of the large intestine and is formed by the anastomosis of the branches of the ileocolic artery, right colic artery, middle colic artery, left colic artery and sigmoid artery. If a small artery is occluded, these branches allow blood to reach all segments of the colon.
The arcades are anastomotic loops between the arteries that provide alternative pathways for blood flow. They are more prominent in the small intestine than the large intestine.
Arteriae rectae are small branches that run from the marginal artery to reach the colon.
The ileocolic artery is the branch of the superior mesenteric artery that supplies the caecum, appendix and terminal part of the ileum.
The coronary arteries supply blood to the heart.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 21
Correct
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During a radical mastectomy for advanced breast cancer, the surgeon injured the long thoracic nerve. Which among the following muscles is likely to be affected?
Your Answer: Serratus anterior
Explanation:The long thoracic nerve innervates the serratus anterior muscle which holds the scapula forward and balances the rhomboids and the trapezius muscles which retract the scapula. Injury to this nerve results in a ‘winged scapula’ with a posterior protrusion.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 22
Correct
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Which of the following organs of the abdominal cavity is completely covered by the peritoneum?
Your Answer: Spleen
Explanation:Of the organs listed, the spleen is the only organ that is completely intraperitoneal, that is entirely in the peritoneum. Other completely intraperitoneal organs include the stomach, liver, appendix and the small intestines. The kidney, Inferior vena cava, aorta and the suprarenal glands are all retroperitoneal organs. The pancreas and the duodenum are partially retroperitoneal, with the tail of the pancreas in the peritoneum found in the splenorenal ligament while only the first part of the duodenum is intraperitoneal. For the intraperitoneal organs remember SALTD SPRSS
S = Stomach
A = Appendix
L = Liver
T = Transverse colon
D = Duodenum (only the 1st part)
S = Small intestines
P = Pancreas (only the tail)
R = Rectum (only the upper 3rd)
S = Sigmoid colon
S = Spleen
For retroperitoneal, just remember SADPUCKER:
S = suprarenal glands
A = Aorta and IVC
D = Duodenum (all but the 1st part)
P = Pancreas (all but the tail)
U = Ureter and bladder
C = Colon (ascending and descending)
K = Kidneys
E = Oesophagus
R = Rectum (Lower two-thirds)
For secondarily retroperitoneal remember ‘Pussy Cat Dolls“:
P = Pancreas
C = Colon (only ascending and descending)
D = Duodenum (only parts 2-4) -
This question is part of the following fields:
- Abdomen
- Anatomy
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Question 23
Correct
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A surgeon ligates the left middle suprarenal artery while carrying out a left adrenalectomy. Where does the left middle suprarenal artery originate?
Your Answer: Abdominal aorta
Explanation:Middle suprarenal arteries arise from either side of the abdominal aorta, opposite the superior mesenteric artery.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 24
Correct
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The proximal tubule is the portion of the ductal system of the nephron of the kidney which leads from Bowman's capsule to the loop of Henle. Which of the following is most likely to be seen in a sample of fluid leaving the proximal tubule?
Your Answer: It will have no amino acids
Explanation:The proximal tubule is the portion of the duct system of the nephron leading from Bowman’s capsule to the loop of Henlé. The most distinctive characteristic of the proximal tubule is its brush border (or ‘striated border’). The luminal surface of the epithelial cells of this segment of the nephron is covered with densely packed microvilli forming a border which greatly increases the luminal surface area of the cells, presumably facilitating their reabsorptive function. Glucose, amino acids, inorganic phosphate, and some other solutes are100% reabsorbed via secondary active transport through co-transporters driven by the sodium gradient out of the nephron.
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This question is part of the following fields:
- Physiology
- Renal
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Question 25
Correct
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A 40 year old man sustained a fracture to the surgical neck of his left humerus. Which of the following arteries is suspected to be injured in this case?
Your Answer: Posterior humeral circumflex
Explanation:The posterior humeral circumflex artery arises from the axillary artery and runs with the axillary nerve through the quadrangular space which is bounded laterally by the surgical neck of the humerus. After winding around the surgical neck of the humerus, it is distributed to the deltoid muscle and the shoulder joint. Thus fractures in the surgical neck of the humerus could result in an injury to this artery.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 26
Incorrect
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Calculate the stroke volume in an adult male with the following parameters:
Heart rate 70 beats/min
Arterial [O2] 0.24 ml O2/min
Venous [O2] 0.16 ml O2/mi
Whole body O2 consumption 500 ml/min
Pulmonary diastolic pressure 15 mmHg
Pulmonary systolic pressure 25 mmHg
Wedge pressure 5 mmHg.Your Answer: 75 ml
Correct Answer: 90 ml
Explanation:Fick’s principle states that, VO2 = (CO × CAO2) – (CO × CVO2) where VO2 = oxygen consumption, CO = cardiac output, CAO2 = oxygen concentration of arterial blood and CVO2 = oxygen concentration of venous blood. Thus, CO = VO2/CAO2– CVO2, CO = 500/0.24–0.16, CO = 500/0.8, CO = 6.25 l/min. Cardiac output is also given by product of stroke volume and heart rate. Thus, stroke volume = cardiac output / heart rate = 6.25/70 × 1000 stroke volume = 90 ml approximately.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 27
Incorrect
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Medulloblastoma usually occurs in children between 5 to 9 years old. Where does medulloblastoma commonly originate from?
Your Answer: Fourth ventricle
Correct Answer: Cerebellar vermis
Explanation:Medulloblastoma is the most common malignant brain tumour in children, accounting for 10-20% of primary CNS neoplasms. Most of the tumours originate in the cerebellar vermis.
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This question is part of the following fields:
- Neoplasia
- Pathology
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Question 28
Correct
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A 25-year-old female had a painful abdomen and several episodes of vomiting. She was severely dehydrated when she was brought to the hospital. Her ABG showed a pH 7.7, p(O2) 75 mmHg, p(CO2) 46 mmHg and bicarbonate 48 mmol/l. The most likely interpretation of this ABG report would be:
Your Answer: Metabolic alkalosis
Explanation:Metabolic alkalosis is a primary increase in bicarbonate (HCO3−) with or without compensatory increase in carbon dioxide partial pressure (Pco2); pH may be high or nearly normal. Metabolic alkalosis occurs as a consequence of a loss of H+ from the body or a gain in HCO3 -. In its pure form, it manifests as alkalemia (pH >7.40). As a compensatory mechanism, metabolic alkalosis leads to alveolar hypoventilation with a rise in arterial carbon dioxide tension p(CO2), which diminishes the change in pH that would otherwise occur. Normally, arterial p(CO2) increases by 0.5–0.7 mmHg for every 1 mmol/l increase in plasma bicarbonate concentration, a compensatory response that occurs very rapidly. If the change in p(CO2) is not within this range, then a mixed acid–base disturbance occurs. Likewise, if the increase in p(CO2) is less than the expected change, then a primary respiratory alkalosis is also present. However an elevated serum bicarbonate concentration can also occur due to a compensatory response to primary respiratory acidosis. A bicarbonate concentration greater than 35 mmol/l is almost always caused by metabolic alkalosis (as is the case in this clinical scenario). Calculation of the serum anion gap can also help to differentiate between primary metabolic alkalosis and the metabolic compensation for respiratory acidosis. The anion gap is frequently elevated to a modest degree in metabolic alkalosis because of the increase in the negative charge of albumin and the enhanced production of lactate. However, the only definitive way to diagnose metabolic alkalosis is by performing a simultaneous blood gases analysis, which reveals elevation of both pH and arterial p(CO2) and increased calculated bicarbonate.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 29
Correct
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A specialist registrar was performing the bi-lateral surgical removal of the adrenal glands. He first removed the left adrenal gland before moving on to the right one. However, the registrar noticed that the removal of the right adrenal gland would be a challenge because of an overlying structure. What was this structure that overlies the right suprarenal glad?
Your Answer: Inferior vena cava
Explanation:The adrenal glands or the suprarenal glands are small glands that are found on top of each of the kidneys. They are retroperitoneal glands. The right adrenal gland is found on top of the right kidney and is closely associated with the inferior vena cava as it directly drains into this large vein. In the case where the right adrenal gland is to be surgically removed, the inferior vena cava might prove a problem to manoeuvre as it overlies the right suprarenal gland. The other blood vessels such as the aorta, right renal, superior mesenteric, splenic artery and the hepatic vein as well as the right crus are not closely associated with either of the suprarenal glands.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 30
Correct
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A drug abuser developed an infection which spread from the dorsum of the hand to the medial side of the arm along the course of the large cutaneous vein. Which vein is involved?
Your Answer: Basilic
Explanation:The basilic vein is one of two veins found in the forearm, the other is the cephalic vein. These veins originate from the deep venous arch of the hand. The cephalic vein ascends along the lateral side of the forearm, and the basilic vein runs up the medial side of the forearm.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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SESSION STATS - PERFORMANCE PER SPECIALTY
