-
Question 1
Correct
-
A 7-month-old abandoned baby with congenital non-communicating hydrocephalus is hosted by a clinic at its new-born hostel. A CT scan of the baby's brain reveals what might be a blockage of the ventricular system between the third and the fourth ventricles. Which of the following is the most likely blocked structure?
Your Answer: Cerebral aqueduct
Explanation:The drainage of cerebral spinal fluid from the third ventricle to the fourth ventricle is carried out by the cerebral aqueduct. The cerebral aqueduct is the narrowest passageway in the entire ventricular system and thus forms the most common site of blockage of flow of cerebrospinal fluid. The interventricular foramen allows passage of CSF to the third ventricle. The foramen of Luschka and Magendie are located on the fourth ventricle and allow passage of CSF to the subarachnoid space from the ventricular system. The pontine cistern is a space located on the ventral aspect of the pons. The cisterna magna is an opening on the subarachnoid space between the pia matter and the arachnoid.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 2
Correct
-
A 37-year-old woman with a history of rheumatic heart disease presents with 10 days recurrent low fever. Patient underwent laboratory work up and was diagnosed with infective endocarditis. What is the most likely organism that caused the infective endocarditis in this patient?
Your Answer: Streptococcus viridans
Explanation:Subacute bacterial endocarditis is often due to streptococci of low virulence, mainly streptococcus viridans. It is a mild to moderate illness which progresses slowly over weeks and months (>2weeks) and has low propensity to hematogenously seed to extracardiac sites.
-
This question is part of the following fields:
- Microbiology
- Pathology
-
-
Question 3
Correct
-
Injury to this nerve may result in loss of sensation of the mandibular teeth and bone:
Your Answer: Inferior alveolar nerve
Explanation:The inferior alveolar nerve (sometimes called the inferior dental nerve) is a branch of the mandibular nerve, which is itself the third branch of the trigeminal nerve. The inferior alveolar nerves supply sensation to the lower teeth of the mandible.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 4
Incorrect
-
The dilator pupillae muscle is innervated by postganglionic sympathetic fibres. Where do the postganglionic sympathetic fibres originate?
Your Answer: Ciliary ganglion
Correct Answer: Superior cervical ganglion
Explanation:The postganglionic sympathetic axons are derived from the superior cervical ganglion and innervate the eye and lacrimal gland allowing for vasoconstriction of the iris and sclera, pupillary dilation, widening of the palpebral fissure, and a reduction in tear production.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 5
Correct
-
During cardiac catheterisation, if the blood sample from the catheter shows an oxygen saturation of 70%, and the pressure ranging from 12 to 24 mm Hg, it implies that the catheter tip is located in the:
Your Answer: Pulmonary artery
Explanation:Normal values for various parameters are as follows:
Systolic arterial blood pressure (SBP): 90–140 mmHg.
Diastolic arterial blood pressure: 60–90 mmHg.
Mean arterial blood pressure (MAP): SBP + (2 × DBP)/3 (normal range: 70-105 mmHg).
Right atrial pressure (RAP): 2–6 mmHg.
Systolic right ventricular pressure (RVSP): 15–25 mmHg.
Diastolic right ventricular pressure (RVDP): 0–8 mmHg.
Pulmonary artery pressure (PAP): Systolic (PASP) is 15-25 mmHg and Diastolic (PADP) is 8–15 mmHg.
Pulmonary artery wedge pressure (PAWP): 6–12 mmHg.
Left atrial pressure (LAP): 6–12 mmHg.
Thus, the given value indicates that the position of catheter tip is likely to be in the pulmonary artery.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 6
Correct
-
A patient who underwent emergency appendicectomy complains of having numbness (paraesthesia) of the skin at the pubic region. Which nerve was most likely injured in the operation?
Your Answer: Iliohypogastric
Explanation:The iliohypogastric nerve comes from L1 and emerges from the upper part of the lateral border of the psoas major. It then crosses obliquely in front of the quadratus lumborum to the iliac crest where it perforates the posterior part of transversus abdominis and divides between that muscle and the internal oblique into a lateral and an anterior cutaneous branch. This provides sensory innervation to the skin of the lower abdominal wall, upper hip and upper thigh.
The genitofemoral nerve also comes from the lumbar plexus that innervates the skin of the anterior scrotum or labia majora and upper medial thigh.
The subcostal nerve is the ventral primary ramus of T12 providing sensory innervation to the anterolateral abdominal wall in an area superior to the pubic region.
A spinal nerve owing to their deep location would not have been injured in the procedure.
-
This question is part of the following fields:
- Abdomen
- Anatomy
-
-
Question 7
Correct
-
In the adult heart, the sinus venosus gives rise to the:
Your Answer: Coronary sinus
Explanation:The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. It exists distinctly only in the embryonic heart (where it is found between the two venae cavae); however, the sinus venosus persists in the adult. In the adult, it is incorporated into the wall of the right atrium to form a smooth part called the sinus venarum, which is separated from the rest of the atrium by a ridge of fibres called the crista terminalis. The sinus venosus also forms the SA node and the coronary sinus.
-
This question is part of the following fields:
- Anatomy
- Embryology
-
-
Question 8
Correct
-
In the kidney, the macula densa is an area of closely packed specialized cells lining the wall of the:
Your Answer: Distal convoluted tubule
Explanation:In the kidney, the macula densa is an area of closely packed specialised cells lining the region of the distal convoluted tubule (DCT) lying next to the glomerular vascular pole. The cells of the macula densa are sensitive to the ionic content and water volume of the fluid in the DCT, producing signals that promote renin secretion by other cells of the juxtaglomerular apparatus.
-
This question is part of the following fields:
- Physiology
- Renal
-
-
Question 9
Correct
-
A patient in the intensive care unit developed hyperphosphatemia. The phosphate level is 160 mmol/L. Which of the following is most likely responsible for this abnormality?
Your Answer: Renal insufficiency
Explanation:Hyperphosphatemia is an electrolyte disturbance in which there is an abnormally elevated level of phosphate in the blood. It is caused by conditions that impair renal phosphate excretion (ex: renal insufficiency, hypoparathyroidism, parathyroid suppression) and conditions with massive extracellular fluid phosphate loads (ex: rapid administration of exogenous phosphate, extensive cellular injury or necrosis, transcellular phosphate shifts).
-
This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
-
-
Question 10
Incorrect
-
A 48-year-old man smoker presented to the doctor complaining of a persistent cough and shortness of breath. A chest X-ray indicated the presence of a right upper lung mass. Biopsy of the mass revealed the presence of pink cells with large, irregular nuclei. What is the most probable diagnosis?
Your Answer: Small cell anaplastic carcinoma
Correct Answer: Squamous cell carcinoma
Explanation:Squamous cell carcinoma, is a type of non-small cell lung cancer that accounts for approximately 30% of all lung cancers. The presence of squamous cell carcinoma is often related with a long history of smoking and the presence of persistent respiratory symptoms. Chest radiography usually shows the presence of a proximal airway lesion. Histological findings include keratinisation that takes the form of keratin pearls with pink cytoplasm and cells with large, irregular nuclei.
-
This question is part of the following fields:
- Pathology
- Respiratory
-
-
Question 11
Correct
-
In a cardiac cycle, what event does the opening of the atrioventricular (AV) valves coincide with?
Your Answer: Beginning of diastole
Explanation:Cardiac diastole refers to the time period when the heart is relaxed after contraction and is preparing to refill with blood. Both ventricular and atrial diastole are together known as complete cardiac diastole. At its beginning, the ventricles relax, causing a drop in the ventricular pressure. As soon as the left ventricular pressure drops below that in left atrium, the mitral valve opens and there is ventricular filling of blood. Similarly, the tricuspid valve opens filling the right atrium.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 12
Correct
-
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.
-
This question is part of the following fields:
- Physiology
- Renal
-
-
Question 13
Correct
-
In relation to the muscles of facial expression, It is true to say:
Your Answer: They are in the same subcutaneous plane as the platysma muscle
Explanation:The facial muscles generally originate from the facial bones and attach to the skin, in the same plane as the platysma muscle. They are all innervated by cranial nerve VII (the facial nerve). The occipitofrontalis muscle consists of two parts: The occipital belly, near the occipital bone, and the frontal belly, near the frontal bone.
-
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 14
Correct
-
Which of the following is the source of blood supply to the artery of the round ligament at the head of the femur?
Your Answer: Obturator artery
Explanation:The posterior branch of the obturator artery provides an articular branch to the head of the femur.
-
This question is part of the following fields:
- Anatomy
- Lower Limb
-
-
Question 15
Correct
-
A 60-year-old male who was admitted due to cerebrovascular disease on his 5th hospital stay developed pneumonia. The most likely organism that causes hospital acquired pneumonia is pseudomonas aeruginosa. What is the most likely mechanism for the pathogenesis on pseudomonas infection?
Your Answer: Exotoxin
Explanation:Pseudomonas aeruginosa is a common Gram-negative, rod-shaped bacterium that can cause disease in plants and animals, including humans. It is citrate, catalase, and oxidase positive. P. aeruginosa uses the virulence factor exotoxin A to inactivate eukaryotic elongation factor 2 via ADP-ribosylation in the host cell, much the same as the diphtheria toxin does. Without elongation factor 2, eukaryotic cells cannot synthesize proteins and necrotise. The release of intracellular contents induces an immunologic response in immunocompetent patients.
-
This question is part of the following fields:
- Microbiology
- Pathology
-
-
Question 16
Correct
-
Into which vein does the left and right inferior thyroid veins drain?
Your Answer: Brachiocephalic vein
Explanation:The brachiocephalic vein is formed by the confluence of the subclavian and internal jugular veins. In addition it receives drainage from: the left and right internal thoracic veins (also called internal mammary veins), left and right inferior thyroid veins and the left superior intercostal vein.
The superior thyroid veins and middle thyroid veins drain into the internal jugular vein. The right and left inferior thyroid veins to drain into their respective brachiocephalic veins (right and left). -
This question is part of the following fields:
- Anatomy
- Head & Neck
-
-
Question 17
Correct
-
A 42 year old women presents with end stage renal failure and is prepared to receive a kidney from her husband. HLA testing showed that they are not a 100% match and she is given immunosuppressant therapy for this. Three months later when her renal function tests were performed she showed signs of deteriorating renal function, with decreased renal output, proteinuria of +++ and RBCs in the urine. She was given antilymphocyte globulins and her condition reversed. What type of graft did this patient receive?
Your Answer: Allograft
Explanation:Allograft describes a graft between two of the same species. As the donor and the recipients are history-incompatible, rejection of the graft is common and is controlled by immunosuppressive drug therapy. Isograft and syngraft are synonymous and referred to a graft transferred between genetically identical individuals e.g. identical twins. In this case rejection is rare as they are history-compatible.
Autograft refers to transfer of one part of the body to another location.
Xenograft is transfer of tissue from another species e.g. pig to human in valve replacement surgeries and rejection is very high.
-
This question is part of the following fields:
- Inflammation & Immunology; Renal
- Pathology
-
-
Question 18
Correct
-
Regarding the extensor retinaculum of the wrist, which of these is CORRECT?
Your Answer: It prevents the tendons of the posterior compartment of the forearm from ‘bowstringing’ when the hand is extended at the wrist
Explanation:This extensor retinaculum, as the name indicates, holds the tendons of the extensors against the dorsal surface of the distal radius and ulna. Therefore, the correct answer is that it prevents bowstringing of the extensor tendons with wrist extension. It forms compartments between it and its bony attachment, and these compartments guide and hold the tendons.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 19
Correct
-
Gastrocnemius, semimembranosus and semitendinosus together with which other muscle form the boundaries of the popliteal fossa?
Your Answer: Biceps femoris
Explanation:The popliteal fossa is located at the back of the knee. It is bounded laterally by the biceps femoris above and the plantaris and lateral head of the gastrocnemius below and medially by the semitendinosus and semimembranosus above and by the medial head of the gastrocnemius below.
-
This question is part of the following fields:
- Anatomy
- Lower Limb
-
-
Question 20
Correct
-
Which of the following changes in the histology of the cell is most likely to be accompanied by disruption of the cell membrane following an injury?
Your Answer: Coagulative necrosis
Explanation:The process of necrosis ends with the rupture of the cell membrane and the consequent release of the cellular components into the surrounding tissue. Apoptosis, pyknosis and karyorrhexis are not reversible events but the cell membrane remains intact. Cloudy swelling and hydropic changes are also reversible but again the cell membrane remains intact and they are therefore different and distinct from necrosis.
-
This question is part of the following fields:
- Cell Injury & Wound Healing
- Pathology
-
-
Question 21
Correct
-
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.
-
This question is part of the following fields:
- Microbiology
- Pathology
-
-
Question 22
Correct
-
An 80 year-old quadriplegic man has been lying supine for 7 weeks in a critical care ward. He develops a right lung abscess that is draining by gravity to a particular region of the lung. Which is the most likely site of pus collection?
Your Answer: Superior segment of the lower lobe
Explanation:The superior segmental bronchus of the lower lobe of the right lung branches posteriorly off the intermediate bronchus or the inferior lobe bronchus. It is therefore more likely to receive fluid or foreign bodies that enter the right main bronchus especially when the patient is supine.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 23
Correct
-
Which of the following tumours is very radiosensitive?
Your Answer: Seminoma
Explanation:Seminoma is the most radiosensitive tumour and responds well to radiation therapy after unilateral orchidectomy. The ipsilateral inguinal areas are routinely not treated however, depending on the stage, the mediastinum and the left supraclavicular regions may also be irradiated.
-
This question is part of the following fields:
- Neoplasia; Urology
- Pathology
-
-
Question 24
Correct
-
A victim of assault in a domestic violence is stabbed in the left chest. The tip of the pen knife entered the pleural space just above the cardiac notch. Luckily the lung was spared as it would only occupy this space during deep inspiration. Which of these structures was pierced by the knife?
Your Answer: Costomediastinal recess
Explanation:The costomediastinal recess is located immediately next to the cardiac notch. The medial aspect of the superior lobe of the left lung, when fully inflated expands to this place. The lung wouldn’t enter the anterior or the posterior mediastinum which are found between the two pleural cavities.
The costodiaphragmatic recess is the lowest extent of the pleural cavity where the inferior lobes of the lungs would expand into in deep inhalation.
The cupola, is the part of the pleural cavity that extends above the first rib into the root of the neck. The superior most part of the superior lobe of the lung might extend into this part.
Pulmonary ligament: pleural fold that is located below the root of the lung where the visceral pleura and the mediastinal pleura are in continuity.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 25
Correct
-
A 28 years old women presents with a history of chronic cough with fever for the past 2 months. A chest x ray revealed a diffuse bilateral reticulonodular pattern. A transbronchial biopsy was performed and histological examination showed focal areas of inflammation with epithelioid macrophages, Langhans cells and lymphocytes. Which of the immune reaction is responsible for this?
Your Answer: Type IV hypersensitivity
Explanation:A reactivated tuberculosis with granuloma formation is characteristic of type IV reaction. It is also called a delayed type of hypersensitivity reaction and takes around 2-8 days to deliver. It is a cell mediated response with the involvement of CD8 and CD4 cells and the release of IL-1 from macrophages that further activate these CD cells.
Granulomatous reactions are mostly cell-mediated.
Type I reactions are allergic and anaphylactic reactions and type II are complement-mediated immune reactions.
-
This question is part of the following fields:
- Inflammation & Immunology; Respiratory
- Pathology
-
-
Question 26
Correct
-
An 80 year-old lady presents to the out patient clinic complaining of chest pain of 2 months' duration with a normal electrocardiogram and cardiac enzymes. A computed tomographic scan is done which reveals a mass lesion involving a structure in the middle mediastinum. Which among the following structures could be involved?
Your Answer: Ascending aorta
Explanation:The middle mediastinum is the broadest part of the mediastinal cavity containing the heart enclosed in the pericardium, ascending aorta, lower half of the superior vena cava with the azygos vein opening into it, the bifurcation of the trachea and the two bronchi, the pulmonary artery with its branches, pulmonary veins, phrenic nerves and bronchial lymph nodes. The most likely structure involved is the ascending aorta, perhaps with an aneurysm.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 27
Correct
-
An old man fell and fractured a carpal bone articulating with the pisiform bone. Which bone was most likely fractured?
Your Answer: Triquetral
Explanation:The pisiform bone has an oval facet for articulation with the triquetral bone. The pisiform bone is a sesamoid bone, and is anterior to the other carpal bones.
-
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 28
Incorrect
-
A biopsy taken from the respiratory passage of a 37 year old male, chronic smoker will mostly likely show which cellular adaptation?
Your Answer: Squamous cell anaplasia
Correct Answer: Stratified squamous metaplasia
Explanation:Metaplasia is a change in the cell type caused in part due to an extrinsic stress on the organ. It involves a change in the surface epithelium from one cell type to the another, most commonly squamous to columnar. This is a reversible process, and removal of the stress should theoretically reverse the surface epithelium back to normal morphology. Respiratory tract metaplasia is a classic example, in which the normal pseudostratified columnar epithelium is replaced by stratified squamous epithelium to better cope with the stress. Under continuous stress metaplasia can progress to dysplasia which is a disordered growth of cells eventually leading to the development of carcinoma.
-
This question is part of the following fields:
- Cell Injury & Wound Healing; Respiratory
- Pathology
-
-
Question 29
Correct
-
A sexually active 21 year old man presents with the history of dysuria for the past 3 days. Urine culture confirmed Neisseria gonorrhoeae and smear showed abundant neutrophils. Which of the following mediators is responsible for causing diapedesis of the neutrophils to reach the site of infection?
Your Answer: Complement C5a
Explanation:C5a is part of the complement cascade and is released frim the complement C5. It acts as a chemotactic factor for neutrophils. Other chemotactic mediators are TNF, leukotrienes and bacterial products.
Bradykinin is associated with the production of pain and vasodilation.
Hageman factor is a clotting factor.
Histamine causes vasodilation.
C3B causes opsonisation.
IL-6 and IL-12 are inflammatory mediators causing B cell maturation and mediating inflammation and prostaglandins are involved with pain, increasing cell permeability and vasodilation.
-
This question is part of the following fields:
- Inflammation & Immunology; Urology
- Pathology
-
-
Question 30
Correct
-
A 45-year old man presents with sclerosing cholangitis, blood in his stools and apparent iron deficiency anaemia. What will be the most likely finding on his colonic biopsy?
Your Answer: Pseudopolyps
Explanation:Sclerosing cholangitis along with the passage of blood in stools suggests ulcerative colitis affecting the mucosa and submucosa of rectum and colon, with a sharp demarcation with the normal tissue. The musclaris layer is involved in severe cases. Initially, the mucosa is erythematous, friable with scattered haemorrhagic areas and loss of normal vascular pattern. Severe disease is indicated by presence of large mucosal ulcers with purulent exudate. There can be islands of normal mucosa between the ulcerated mucosa, along with few hyperplastic inflammatory mucosal lesions (pseudopolyps). Ulcerative colitis does not lead to development of fistulas or abscesses.
-
This question is part of the following fields:
- Gastrointestinal; Hepatobiliary
- Pathology
-
SESSION STATS - PERFORMANCE PER SPECIALTY
