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Question 1
Incorrect
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A 27-year-old man has been diagnosed with testicular cancer and has spread to the regional lymph nodes.
The lymph from the testes will drain to which of the following nodes?Your Answer: Superficial inguinal lymph nodes
Correct Answer: Para-aortic lymph nodes
Explanation:Testes are retroperitoneal organs and its lymphatic drainage is to the lumbar and para-aortic nodes along the lumbar vertebrae.
The scrotum is the one which drains into the nearby superficial inguinal nodes.
The glans penis and clitoris drains into the deep inguinal lymph nodes.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 2
Incorrect
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In which of the following cases is intravenous phenytoin contraindicated?
Your Answer: Hepatic impairment
Correct Answer: Second degree heart block
Explanation:Phenytoin Contraindications include:
Hypersensitivity
Sinus bradycardia
Sinoatrial block
Second and third degree A-V block
Adams-Stokes syndrome
Concurrent use with delavirdine
History of prior acute hepatotoxicity attributable to phenytoin -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 3
Correct
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What is the mechanism of action of penicillin antibiotics:
Your Answer: Inhibition of bacterial cell wall synthesis
Explanation:Penicillins and the other ß-lactam antibiotics are bactericidal. They produce their antimicrobial action by preventing cross-linkage between the linear peptidoglycan polymer chains that make up the bacterial cell wall. They, therefore, inhibit cell wall synthesis.
The integrity of the ß-lactam ring is essential for antimicrobial activity. Many bacteria (including most Staphylococci) are resistant to benzylpenicillin and phenoxymethylpenicillin because they produce enzymes (penicillinases, ß-lactamases) that open the ß-lactam ring. -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 4
Incorrect
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A 46-year-old male who is suffering from a chest infection. You decide to start giving the patient antibiotics, however he is allergic to penicillin. You consult with one of your co-workers about the best choice of antibiotic to give.
From the following choices, which is considered an example of bacteriostatic antibiotic?
Your Answer: Ciprofloxacin
Correct Answer: Trimethoprim
Explanation:Antibiotics that are bactericidal kill bacteria, while antibiotics that are bacteriostatic limit their growth or reproduction. The antibiotics grouped into these two classes are summarized in the table below:
Bactericidal antibiotics
Bacteriostatic antibioticsVancomycin
Metronidazole
Fluoroquinolone, such as ciprofloxacin
Penicillins, such as benzylpenicillin
Cephalosporin, such as ceftriaxone
Co-trimoxazole
Tetracyclines, such as doxycycline
Macrolides, such as erythromycin
Sulphonamides, such as sulfamethoxazole
Clindamycin
Trimethoprim
Chloramphenicol -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 5
Incorrect
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Which of the following risk ratios indicates no difference in risk between two groups:
Your Answer: ∞
Correct Answer: 1
Explanation:A risk ratio of 1 indicates no difference in risk between groups.If the risk ratio of an event is > 1, the rate of that event is increased in the exposed group compared to the control group.If the risk ratio is < 1, the rate of that event is reduced in the exposed group compared to the control group.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 6
Correct
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How does aspirin mediate its antiplatelet effect:
Your Answer: It irreversibly inhibits cyclo-oxygenase
Explanation:Aspirin irreversibly inhibits cyclooxygenase and blocks the platelet production of thromboxane A2 (TXA2), thus inhibiting platelet aggregation.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 7
Correct
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At rest, saliva is produced predominantly by which of the following:
Your Answer: Submandibular gland
Explanation:At rest, most saliva is produced by the submandibular gland (65%). When stimulated by the autonomic nervous system, about 50% of saliva is produced by the parotid gland with only 30% produced by the submandibular gland.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 8
Correct
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Which of the following problems is associated with Helicobacter pylori infection?
Your Answer: Gastric malignancy
Explanation:Helicobacter pylori is a ubiquitous organism that is present in about 50% of the global population. Chronic infection with H pylori causes atrophic and even metaplastic changes in the stomach, and it has a known association with peptic ulcer disease. The most common route of H pylori infection is either oral-to-oral or faecal-to-oral contact.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 9
Correct
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A suicidal patient had lacerated his wrist, which resulted in an ulnar nerve injury. Which of the following will confirm the presence of an ulnar nerve injury?
Your Answer: Claw hand appearance
Explanation:An ulnar injury may result in abnormal sensations in the little finger and ring finger, usually on the palm side, weakness, and loss of coordination of the fingers.
A claw like deformity of the hand and wrist is present. Pain, numbness, decreased sensation, tingling, or burning sensation in the areas controlled by the nerve are also possible.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 10
Incorrect
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Which of these statements about experimental studies is true?
Your Answer:
Correct Answer: Randomisation serves to remove potential bias
Explanation:In experimental studies, the researcher introduces an intervention and studies the effect. The study subjects are allocated into different groups by the investigator through the use of randomisation. Randomisation serves to remove any potential bias.
A cohort study is a form of longitudinal, observational study that follows a group of patients (the cohort) over a period of time to monitor the effects of exposure to a proposed aetiological factor upon them.
A case-control study is a type observational study. Here, patients who have developed a disease are identified and compared on the basis of proposed causative factors that occurred in the past, to a control group.
Clinical trials are experimental studies. Examples include: double blind, single blind, and unblinded studies(both patient and researcher are aware of the treatment they receive)
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This question is part of the following fields:
- Evidence Based Medicine
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Question 11
Incorrect
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A 29-year-old volunteer returns from a recent trip to the middle east with profuse watery diarrhoea. You make a diagnosis of cholera and organize a hospital admission for rehydration with intravenous fluids.
What is the mechanism of action of cholera toxin?
Your Answer:
Correct Answer: ADP-ribosylation of the G regulatory protein
Explanation:Cholera is caused by Vibrio cholerae, a motile, Gram-negative, curved bacillus. It is transmitted through water and food (especially seafood) and is primarily a disease seen in developing countries where there is poor sanitation and lack of safe water supplies.
The cholera toxin leads to stimulation of adenyl cyclase, ADP-ribosylation of the G regulatory protein, inactivation of GTPase leading to active outpouring of NaCl.
The cholera toxin consists of an A (the toxin) and B subunit. The B subunit attaches to the gut mucosa and presents the A subunit to the cell. The toxin stimulates adenyl cyclase by irreversible ADP-ribosylation of the GTP binding domain of adenyl cyclase leading to the opening of chloride channels resulting in an outpouring of NaCl and water into the lumen of the gut and causing secretory diarrhoea.
Incubation period is between 2 and 5 days, but can be as short as just a few hours.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 12
Incorrect
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Which of the following nerves supply the superficial head of the flexor pollicis brevis muscle?
Your Answer:
Correct Answer: The recurrent branch of the median nerve
Explanation:The two heads of the flexor pollicis brevis usually differ in their innervation. The superficial head of flexor pollicis muscle receives nervous supply from the recurrent branch of the median nerve, whereas the deep head receives innervation from the deep branch of the ulnar nerve, derived from spinal roots C8 and T1.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 13
Incorrect
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Which of the following statements is true regarding the extensor pollicis longus?
Your Answer:
Correct Answer: It is innervated by the posterior interosseous nerve
Explanation:Extensor pollicis longus is part of the deep extensors of the forearm together with extensor pollicis brevis, abductor pollicis longus, extensor indicis and supinator muscles. It is located on the posterior aspect of forearm, extending from the middle third of the ulna, and adjacent interosseous membrane, to the distal phalanx of the thumb.
Extensor digitorum is innervated by posterior interosseous nerve which is a continuation of a deep branch of radial nerve (root value C7 and C8).
Extensor pollicis brevis receives its blood supply from the posterior interosseous artery and perforating branches of the anterior interosseous artery.
The main action of extensor pollicis longus is extension of the thumb at the metacarpophalangeal and interphalangeal joints. Extension at the metacarpophalangeal joint occurs in synergy with extensor pollicis brevis muscle. When the thumb reaches the full extension or abduction, extensor pollicis longus can also assist in adduction of the thumb.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 14
Incorrect
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You are going to prescribe a NSAID to a 50-year-old male patient for his back pain. Which of the following NSAIDs is least likely to cause gastrointestinal side effects:
Your Answer:
Correct Answer: Ibuprofen
Explanation:NSAIDs are associated with serious gastrointestinal irritation and drug-induced ulcers.
Among the NSAIDs included in the choices, ibuprofen has the lowest risk.
Piroxicam, ketoprofen, and ketorolac trometamol are associated with the highest risk of serious upper gastrointestinal side effects.
Indomethacin, diclofenac, and naproxen are associated with an intermediate risk of serious upper gastrointestinal side effects.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 15
Incorrect
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A 7-days-old neonate is taken to the emergency department. She's pyretic, lethargic, and unresponsive, and her fontanelle has bulged. Antibiotics are started, and a lumbar puncture reveals Gram-negative rods. Which pathogen is most likely to be the cause:
Your Answer:
Correct Answer: Escherichia coli
Explanation:Among neonates, group B streptococci (GBS) are the most commonly identified causes of bacterial meningitis, implicated in roughly 50% of all cases. Escherichia coli(Gram-negative rods) accounts for another 20%. Thus, the identification and treatment of maternal genitourinary infections is an important prevention strategy.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 16
Incorrect
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A 20-year-old male patient lives in a travelling community and has never received any vaccinations. He presents to you with fever.
Which of these statements concerning indications and contraindications for vaccination is TRUE?
Your Answer:
Correct Answer: Inactivated vaccines are safe in pregnancy
Explanation:All vaccines are contraindicated in individuals with: A confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.
A confirmed anaphylactic reaction to a component in the vaccine e.g. neomycinThere is no evidence that vaccinating pregnant women with inactivated vaccine or toxoids harms the woman or foetus.
The current protocol is that a child with history of egg allergy can be safely vaccinated with Fluenz tetra. However, if they had a previous severe anaphylaxis to egg requiring intensive care, then Flenz tetra is contraindicated.
BCG, yellow fever or oral typhoid vaccinations are not safe in HIV positive patients.
The normal times recommended for immunization of full-term babies should also be applied to premature infants and correction for gestational age should not be implemented.
Concurrent antibiotic therapy is not a contraindication to vaccination.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 17
Incorrect
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Identify the type of graph described below:
A graph wherein the frequency distribution is represented by adjoining vertical bars and cases are stacked in adjoining columns. It can be used for continuous quantitative data, such as to analyse outbreak data to show an epidemic curve.Your Answer:
Correct Answer: Histogram
Explanation:A histogram is used to demonstrate the distribution of continuous quantitative data. It is a very familiar graphical display device for representing the distribution of a single batch of data. The range of the data is divided into class intervals or bins, and the number of values falling into each interval is counted. The histogram then consists of a series of rectangles whose widths are defined by the class limits implied by the binwidths, and whose heights depend on the number of values in each bin. Histograms quickly reveal such attributes of the data distribution as location, spread, and symmetry. If the data are multimodal (i.e., more than one “hump” in the distribution of the data), this is quickly evident as well.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 18
Incorrect
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Which of the following is caused by an alpha-1 antitrypsin deficiency?
Your Answer:
Correct Answer: Early onset emphysema
Explanation:Mucus contains chemicals such as alpha-1-antitrypsin, lysozyme, and IgA that protect the airway from pathogens and damaging proteases released from dead bacteria and immune cells. Early-onset emphysema results from a genetic deficit of alpha-1-antitrypsin, which is caused by unregulated protease activity in the lungs, which results in the degradation of elastin in the alveoli.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 19
Incorrect
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From which of the following cell types are platelets derived?
Your Answer:
Correct Answer: Megakaryocytes
Explanation:Synthesis of platelets occurs in the bone marrow by fragmentation of megakaryocytes cytoplasm, derived from the common myeloid progenitor cell. The average time for differentiation of the human stem cell to the production of platelets is about 10 days. The major regulator of platelet formation is thrombopoietin and 95% of this is produced by the liver. Normal platelet count is 150 – 450 x 109/L and the normal lifespan of a platelet is about 10 days. Usually about one-third of the marrow output of platelets may be trapped at any one time in the normal spleen.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 20
Incorrect
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A 19-year-old woman presents with dysuria and vaginal discharge. A swab was taken for culture. Culture results showed the presence of Neisseria gonorrhoeae infection. Treatment of azithromycin and doxycycline was started.
Which of the following statements is considered correct regarding Neisseria gonorrhoeae?Your Answer:
Correct Answer: Throat swabs can be used for diagnosis
Explanation:Neisseria gonorrhoeae is a Gram-negative diplococcus that causes gonorrhoea. Gonorrhoea is an acute pyogenic infection of nonciliated columnar and transitional epithelium; infection can be established at any site where these cells are found. Gonococcal infections are primarily acquired by sexual contact and occur primarily in the urethra, endocervix, anal canal, pharynx, and conjunctiva.
In men, acute urethritis, usually resulting in purulent discharge and dysuria (painful urination), is the most common manifestation. The endocervix is the most common site of infection in women. Symptoms of infection, when present, include dysuria, cervical discharge, and lower abdominal pain. Some cases in women may be asymptomatic leading to complications such as pelvic inflammatory disease. Blood-borne dissemination occurs in less than 1% of all infections, resulting in purulent arthritis and rarely septicaemia. Fever and a rash on the extremities can also be present. Other conditions associated with N. gonorrhoeae include anorectal and oropharyngeal infections. Infections in these sites are more common in men who have sex with men but can also occur in women.
Pharyngitis is the chief complaint in symptomatic oropharyngeal infections, whereas discharge, rectal pain, or bloody stools may be seen in rectal gonorrhoea. Approximately 30% to 60% of women with genital gonorrhoea have concurrent rectal infection. Newborns can acquire ophthalmia neonatorum, a gonococcal eye infection, during vaginal delivery through an infected birth canal.
Specimens collected for the recovery of N. gonorrhoeae may come from genital sources or from other sites, such as the rectum, pharynx, and joint
fluid. According to the 2010 STD Treatment guidelines, cephalosporins (e.g., ceftriaxone, cefixime) are currently recommended treatments. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 21
Incorrect
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Which of the following movements is controlled by the pectoralis major muscle?
Your Answer:
Correct Answer: Flexion, adduction and medial rotation of the humerus
Explanation:The pectoralis major is a muscle that runs across the top of the chest and connects to a ridge on the back of the humerus (the bone of the upper arm).
Adduction, or lowering, of the arm (opposed to the deltoideus muscle) and rotation of the arm forward around the axis of the body are two of its main functions.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 22
Incorrect
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An ambulance transports a 37-year-old woman who is having a seizure. She is moved to resuscitation and given a benzodiazepine dose, which quickly ends the seizure. You later learn that she has epilepsy and is usually treated with carbamazepine to control her seizures.
What is carbamazepine's main mechanism of action?Your Answer:
Correct Answer: Sodium channel blocker
Explanation:Carbamazepine is primarily used to treat epilepsy, and it is effective for both focal and generalised seizures. It is not, however, effective in the treatment of absence or myoclonic seizures. It’s also commonly used to treat neuropathic pain, as well as a second-line treatment for bipolar disorder and as a supplement for acute alcohol withdrawal.
Carbamazepine works as a sodium channel blocker that preferentially binds to voltage-gated sodium channels in their inactive state. This prevents an action potential from firing repeatedly and continuously.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 23
Incorrect
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A 50-year-old man presents with headaches, lethargy, hypertension, and electrolyte disturbance. A diagnosis of primary hyperaldosteronism is made.
Which biochemical pictures would best support this diagnosis?
Your Answer:
Correct Answer: Hypokalaemic metabolic alkalosis
Explanation:When there are excessive levels of aldosterone outside of the renin-angiotensin axis, primary hyperaldosteronism occurs. High renin levels will lead to secondary hyperaldosteronism.
The classical presentation of hyperaldosteronism when symptoms are present include:
Hypokalaemia
Metabolic alkalosis
Hypertension
Normal or slightly raised sodium levels -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 24
Incorrect
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Mast cells play a significant part in which of the following?
Your Answer:
Correct Answer: Allergic disease
Explanation:Mast cells play a central role in the response to allergen challenges. The activation of mast cells results in both an early and a delayed phase of inflammation. Mast cells have been implicated in both physiologic and pathogenic processes. Mast cells are important in defence against some bacteria and viruses and contribute to defence against parasites. They are key effector cells in both innate and acquired immunity and are capable of inducing and amplifying both types of responses. Specifically, mast cells are capable of detecting microbial products through surface pattern recognition receptors, and they are involved in the recruitment of other leukocytes, containment of bacterial infections, and tissue repair.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 25
Incorrect
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Regarding the resting membrane potential, which of the following statements is CORRECT:
Your Answer:
Correct Answer: The resting cell membrane is more permeable to K + ions than to Na + ions.
Explanation:A membrane potential is a property of all cell membranes, but the ability to generate an action potential is only a property of excitable tissues. The resting membrane is more permeable to K+and Cl-than to other ions (and relatively impermeable to Na+); therefore the resting membrane potential is primarily determined by the K+equilibrium potential. At rest the inside of the cell is negative relative to the outside. In most neurones the resting potential has a value of approximately -70 mV.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 26
Incorrect
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A 28-year-old asthmatic patient is seen in the Emergency Department following an acute exacerbation. His symptoms start to improve when your consultant gives him a high dose of IV aminophylline.
Which of the following is correct mechanism of action of aminophylline ?Your Answer:
Correct Answer: Inhibition of phosphodiesterase
Explanation:Aminophylline has the following properties:
Phosphodiesterase inhibitor that increases intracellular cAMP and relaxes smooth muscle in the bronchial airways and pulmonary blood vessels.
Mast cell stabilization is achieved by using a non-selective adenosine receptor antagonist. -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 27
Incorrect
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Regarding renal clearance, which of the following statements is CORRECT:
Your Answer:
Correct Answer: The MDRD equation uses plasma creatinine to estimate the GFR making an adjustment for age, sex and race.
Explanation:Clearance is defined as the volume of plasma that is cleared of a substance per unit time. Inulin clearance is the gold standard for measurement of GFR but creatinine clearance is typically used instead. Creatinine is freely filtered and not reabsorbed, but there is a little creatinine tubular secretion. In practice, GFR is usually estimated from the plasma creatinine using a formula e.g. the MDRD equation making an adjustment for age, sex and race.
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This question is part of the following fields:
- Physiology
- Renal
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Question 28
Incorrect
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Which one of these equations best defines lung compliance?
Your Answer:
Correct Answer: Change in volume / change in pressure
Explanation:Lung compliance is defined as change in volume per unit change in distending pressure.
Lung compliance is calculated using the equation:
Lung compliance = ΔV / ΔP
Where:
ΔV is the change in volume
ΔP is the change in pleural pressure.Static compliance is lung compliance in periods without gas flow, and is calculated using the equation:
Static compliance = VT / Pplat − PEEP
Where:
VT = tidal volume
Pplat = plateau pressure
PEEP = positive end-expiratory pressure -
This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 29
Incorrect
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Which of the following nerves has been damaged when a patient presents with a foot drop?
Your Answer:
Correct Answer: Common peroneal nerve
Explanation:The common peroneal nerve often referred to as the common fibular nerve, is a major nerve that innervates the lower extremity. It is one of the two major branches off the sciatic nerve and receives fibres from the posterior divisions of L4 through S2 nerve roots. The common peroneal nerve separates from the sciatic nerve in the distal posterior thigh proximal to the popliteal fossa. After branching off of the sciatic nerve, it continues down the thigh, running posteroinferior to the biceps femoris muscle, and crosses laterally to the head of the lateral gastrocnemius muscle through the posterior intermuscular septum. The nerve then curves around the fibular neck before dividing into two branches, the superficial peroneal nerve (SPN) and the deep peroneal nerve (DPN). The common peroneal nerve does not have any motor innervation before dividing; however, it provides sensory innervation to the lateral leg via the lateral sural nerve.
The superficial peroneal nerve innervates the lateral compartment of the leg, and the deep peroneal nerve innervates the anterior compartment of the leg and the dorsum of the foot. These two nerves are essential in the eversion of the foot and dorsiflexion of the foot, respectively. The superficial and deep peroneal nerves provide both motor and sensory innervation.
The most common presentation with common peroneal nerve injury or palsy is acute foot drop, although symptoms may be progressive and can include sensory loss or pain. Weakness in foot eversion may occur if the superficial peroneal nerve component is involved.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 30
Incorrect
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A 30-year-old man suffers from an open femoral shaft fracture after being involved in a road traffic accident. As a consequence of his injury, the nerve that was damaged innervates the popliteus muscle.
In which of the following nerves is the popliteus muscle innervated by?Your Answer:
Correct Answer: Tibial nerve
Explanation:The popliteus muscle is innervated by the tibial nerve (L4, 5 and S1).
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This question is part of the following fields:
- Anatomy
- Lower Limb
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SESSION STATS - PERFORMANCE PER SPECIALTY
