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Question 1
Correct
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Regarding hepatitis B, which of the following statements is CORRECT:
Your Answer: Chronic hepatitis B infection is indicated by the persistence of HBsAg for more than 6 months.
Explanation:Chronic hepatitis B infection is indicated by the persistence of HBsAg for more than 6 months. Hepatitis B has a long incubation period of about 2 – 6 months. Hepatitis B vaccine has recently been introduced to the routine childhood immunisation schedule – given at 2, 3 and 4 months. It is also given to babies born to hepatitis B infected mothers at birth, four weeks and 12 months old. Treatment of acute hepatitis is supportive. Treatment with antivirals should be considered in chronic infection as responders have a reduced risk of liver damage and liver cancer in the long term.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 2
Correct
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Regarding platelets, which of the following statements is CORRECT:
Your Answer: Platelets are produced in the bone marrow by fragmentation of the cytoplasm of megakaryocytes.
Explanation:Platelets are produced in the bone marrow by fragmentation of the cytoplasm of megakaryocytes, derived from the common myeloid progenitor cell. The time interval from differentiation of the human stem cell to the production of platelets averages 10 days. Thrombopoietin is the major regulator of platelet formation and 95% of this is produced by the liver. The normal platelet count is approximately 150 – 450 x 109/L and the normal platelet lifespan is 10 days. Under normal circumstances, 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 3
Correct
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You're currently treating an infection in a patient and trying to figure out which antibiotic would be best.Which of the following antimicrobial drugs inhibits the formation of cell walls?
Your Answer: Cefuroxime
Explanation:Cefuroxime and other cephalosporin antibiotics are bactericidal ß-lactam antibiotics. They work similarly to penicillins in that they prevent cross-linking between the linear peptidoglycan polymer chains that make up the bacterial cell wall. As a result, they prevent the formation of cell walls.The following is a summary of the various mechanisms of action of various types of antimicrobial agents:1) Inhibition of cell wall synthesisPenicillinsCephalosporinsVancomycin2) Disruption of cell membrane functionPolymyxinsNystatinAmphotericin B3) Inhibition of protein synthesisMacrolidesAminoglycosidesTetracyclinesChloramphenicol4) Inhibition of nucleic acid synthesisQuinolonesTrimethoprim5-nitroimidazolesRifampicin5) Anti-metabolic activitySulphonamidesIsoniazid
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 4
Correct
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Clostridium difficile primarily causes which of the following infectious diseases:
Your Answer: Pseudomembranous colitis
Explanation:Clostridium difficile causes pseudomembranous colitis, an acute inflammatory diarrhoeal disease and an important cause of morbidity and mortality in hospitals. Gas gangrene is primarily caused by Clostridium perfringens. Tetanus is caused by Clostridium tetani. Toxic shock syndrome may be caused by Staphylococcus aureus or Streptococcus pyogenes. Necrotising fasciitis is most commonly caused by Streptococcus pyogenes but has a multitude of causes.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 5
Correct
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After collapsing in his nursing home, a 70-year-old man is brought into the ER. He is a known case of diabetes mellitus and is on medication for it. An RBS of 2.5 mmol/L (3.9-5.5 mmol/L) is recorded in the ER. Out of the following, which medication for diabetes mellitus is MOST likely responsible for his hypoglycaemic episode?
Your Answer: Pioglitazone
Explanation:Pioglitazone is used to treat type 2 diabetes mellitus. It selectively stimulates the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-γ) and to a lesser extent PPAR-α. Of the medications mentioned in this question, only pioglitazone is a recognized cause of hypoglycaemia.
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This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
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Question 6
Correct
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Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer: Metronidazole is usually the antibiotic of choice for tetanus infection.
Explanation:Clostridium tetani infection is predominantly derived from animal faeces and soil. Â Clostridium tetani has exotoxin-mediated effects, predominantly by tetanospasmin which inhibits the release of GABA at the presynaptic membrane throughout the central and peripheral nervous system. Metronidazole has overtaken penicillin as the antibiotic of choice for treatment of tetanus (together with surgical debridement, tetanus toxoid immunisation, and human tetanus immunoglobulin).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 7
Correct
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Which statement concerning aerosol transmission is true?
Your Answer: They can be spread via ventilation systems in hospitals
Explanation:Aerosols are airborne particles less than 5 µm in size containing infective organisms. They usually cause infection of both the upper and/or lower respiratory tract.The organisms can remain suspended in the air for long periods and also survive outside the body. They can be transmitted through the ventilation systems and can spread over great distances. Some examples of organisms transmitted by the aerosol route include: Varicella zoster virus, Mycobacterium tuberculosis and measles virus
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 8
Correct
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During swallowing, which of the following structures primarily closes the tracheal opening:
Your Answer: Epiglottis
Explanation:The vocal cords of the larynx are stronglyapproximated, and the larynx is pulled upwardand anteriorly by the neck muscles. These actions,combined with the presence of ligaments thatprevent upward movement of the epiglottis, causethe epiglottis to swing back over the openingof the larynx. All these effects acting togetherprevent the passage of food into the nose andtrachea. Most essential is the tight approximationof the vocal cords, but the epiglottis helps toprevent food from ever getting as far as the vocalcords. Destruction of the vocal cords or of themuscles that approximate them can causestrangulation.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 9
Correct
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An unrelated medical condition brings a 28-year-old asthmatic man to the Emergency Department. When you look over his meds, you notice that he is taking Theophylline to help with his asthma.Which of the following medicines should you NOT prescribe?
Your Answer: Ciprofloxacin
Explanation:Ciprofloxacin is a cytochrome P450 enzyme inhibitor that raises theophylline levels in the blood. As a result, co-prescribing theophylline should be avoided.The medicines that typically impact theophylline’s half-life and plasma concentration are listed in the table below:Drugs that increase the levels of theophylline in the bloodDrugs that lower theophylline levels in the bloodCalcium channel blockers e.g. VerapamilFluconazoleCimetidineQuinolones, e.g. ciprofloxacinMethotrexateBarbituratesCarbamazepinePhenobarbitalMacrolides, e.g. erythromycinPhenytoin (and fosphenytoin)RifampicinSt. John’s wort
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 10
Incorrect
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Regarding dynamic compression of the airways, which of the following statements is CORRECT:
Your Answer: It is brought about by reflex activation of parasympathetic nerves.
Correct Answer: It occurs during forced expiration.
Explanation:Dynamic compression occurs because as the expiratory muscles contract during forced expiration, all the structures within the lungs, including the airways, are compressed by the positive intrapleural pressure. Consequently the smaller airways collapse before the alveoli empty completely and some air remains within the lungs (the residual volume). Physiologically this is important as a completely deflated lung with collapsed alveoli requires significantly more energy to inflate. Dynamic compression does not occur in normal expiration because the intrapleural pressure is negative throughout the whole cycle.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 11
Correct
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A 23 year old student presents to ED with a widespread maculopapular rash. She recently had a sore throat and was started on a course of antibiotics. The most likely antibiotic that she was prescribed is:
Your Answer: Amoxicillin
Explanation:Maculopapular rashes are commonly seen with ampicillin and amoxicillin. However they are not usually related to true penicillin allergy. Very often, they occur in patients with glandular fever and so, broad-spectrum penicillins should not be used blindly, for management and treatment of a sore throat. There is also an increased risk of rash in patients with acute or chronic lymphocytic leukaemia or in cytomegalovirus infection.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 12
Correct
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Which of the following is NOT an indication for a H1 receptor antihistamine:
Your Answer: Gastroesophageal reflux disease
Explanation:Antihistamines are competitive inhibitors at the H1-receptor (in contrast to H2 receptor antagonists used to decrease gastric acid secretion in gastroesophageal reflux disease).Indications: Allergic rhinitis and conjunctivitisUrticarial rashes, pruritus, insect bites and stingsAngioedemaAnaphylaxis (second line adjunct to adrenaline)Nausea/vomiting and prevention of motion sicknessInsomnia
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 13
Correct
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A 33-year-old heavily muscled man presents with left-sided chest pain. After taking part in a powerlifting competition, he felt a painful snap at the front of his shoulder and chest. There is also the presence of bruising and swelling over the left side of his chest. A ruptured pectoralis major muscle was suspected upon examining the injured area. Which of the following statements regarding the surface markings of the pectoralis major muscle is considered correct?
Your Answer: It inserts into the lateral lip of the bicipital groove of the humerus
Explanation:The pectoralis major is the superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla.Its origin lies anterior surface of the medial half of the clavicle, the anterior surface of the sternum, the first 7 costal cartilages, the sternal end of the sixth rib, and the aponeurosis of the external oblique of the anterior abdominal wall.The insertion of the pectoralis major is at the lateral lip of the intertubercular sulcus of the humerus. There are 2 heads of the pectoralis major, the clavicular and the sternocostal, which reference their area of origin. The function of the pectoralis major is 3-fold and dependent on which heads of muscles are involved:- Flexion, adduction and medial rotation of the arm at the glenohumeral joint- Clavicular head causes flexion of the extended arm- Sternoclavicular head causes extension of the flexed armArterial supply of the pectoralis major, the pectoral artery, arises from the second branch of the axillary artery, the thoracoacromial trunk.The 2 heads of the pectoralis major have different nervous supplies. The clavicular head derives its nerve supply from the lateral pectoral nerve. The medial pectoral nerve innervates the sternocostal head. The lateral pectoral nerve arises directly from the lateral cord of the brachial plexus, and the medial pectoral nerve arises from the medial cord.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 14
Correct
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Which one of these equations best defines lung compliance?
Your 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 / ΔPWhere:ΔV is the change in volumeΔP 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 − PEEPWhere:VT = tidal volumePplat = plateau pressurePEEP = positive end-expiratory pressure
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 15
Correct
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Regarding antacids, which of the following statements is CORRECT:
Your Answer: Antacids are contraindicated in hypophosphataemia.
Explanation:Antacids are contraindicated in hypophosphataemia. Liquid preparations are more effective than tablet preparations. Magnesium-containing antacids tend to be laxative whereas aluminium-containing antacids tend to be constipating. Antacids are best taken when symptoms occur or are expected, usually between meals and at bedtime. Antacids should preferably not be taken at the same time as other drugs since they may impair absorption.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 16
Incorrect
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A 66-year-old female who is a known case of atrial fibrillation comes to the Emergency Department with the complaint of fever and vomiting for the past two days. When her medical chart is reviewed, you see that she takes Warfarin for her arrhythmia. Which ONE of the following medications cannot be prescribed to this patient?
Your Answer: Gentamicin
Correct Answer: Ibuprofen
Explanation:Like other non-steroidal anti-inflammatory drugs, Ibuprofen cannot be given with Warfarin as it would increase the bleeding risk of this patient.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 17
Correct
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Which of the following is the most common cause of hyperthyroidism:
Your Answer: Graves disease
Explanation:Graves disease is the most common cause of hyperthyroidism. It is an autoimmune disease in which autoantibodies against TSH receptors are produced. These antibodies bind to and stimulate these TSH receptors leading to an excess production of thyroid hormones. Therefore, the signs and symptoms of Graves disease are the same as those of hyperthyroidism, reflecting the actions of increased circulating levels of thyroid hormones: increased heat production, weight loss, increased 02 consumption and cardiac output and exophthalmos (bulging eyes, not drooping eyelids). TSH levels will be decreased (not increased) as a result of the negative feedback effect of increased T3 levels on the anterior pituitary.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 18
Incorrect
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A 60-year-old man diagnosed with chronic kidney disease has an elevated creatinine level and a reduced glomerular filtration rate (GFR).Which statement concerning glomerular filtration is true?
Your Answer: The Cockcroft and Gault formula underestimates creatinine in obese patients
Correct Answer: Creatinine is freely filtered at the glomerulus
Explanation:Glomerular filtration is a passive process. It depends on the net hydrostatic pressure across the glomerular capillaries, the oncotic pressure, and the intrinsic permeability of the glomerulus.The mean values for glomerular filtration rate (GFR) in young adults are 130 ml/min/1.73m2 in males and 120 ml/min/1.73m2in females.The GFR declines with age after the age of 40 at a rate of approximately 1 ml/min/year.The Cockcroft and Gault formula overestimates creatinine in obese patients. This is because their endogenous creatinine production is less than that predicted by overall body weight.Creatinine is used in the estimation of GFR because it is naturally produced by muscle breakdown, not toxic, not produced by the kidney, freely filtered at the glomerulus, not reabsorbed from the nephron, and does not alter GFR.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 19
Incorrect
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A patient presents complaining of visual loss. On examination you note a contralateral homonymous hemianopia. Where is the most likely site of the lesion:
Your Answer: Lower optic radiation
Correct Answer: Optic tract
Explanation:At the optic chiasm, fibres from the medial (nasal) half of each retina crossover, forming the right and left optic tracts.The left optic tract contains fibres from the left lateral (temporal) retina and the right medial retina.The right optic tract contains fibres from the right lateral retina and the left medial retina.Each optic tract travels to its corresponding cerebral hemisphere to reach its lateral geniculate nucleus (LGN) located in the thalamus where the fibres synapse.A lesion of the optic tract will cause a contralateral homonymous hemianopia.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 20
Correct
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Funnel plots are typically used to display:
Your Answer: The existence of publication bias in meta-analysis
Explanation:Funnel plots are used to demonstrate the existence of publication bias in meta-analysis. Funnel plots are scatter plots of treatment effects estimated from individual studies on the x axis and some measure of study size on the y axis. Each point on the graph represents one of the studies. A symmetrical inverted funnel shape indicates an absence of publication bias. If there is publication bias, there will be asymmetry of the open wide end due to the absence of small negative results.
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 21
Incorrect
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A 44 year old woman sustains an injury to the median nerve at the elbow after falling awkwardly. Which of the following clinical features are you LEAST likely to see on examination:
Your Answer: Weakness of pronation
Correct Answer: Loss of flexion of the medial two digits
Explanation:Flexion of the index and middle fingers at the IPJs is lost due to paralysis of the flexor digitorum superficialis and the lateral half of the flexor digitorum profundus. Flexion of the MCPJs of the index and middle fingers are lost due to paralysis of the lateral two lumbrical muscles. Flexion of the ring and little fingers are preserved as these are supported by the medial half of the flexor digitorum profundus and the medial two lumbrical muscles, innervated by the ulnar nerve.
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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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What is the pathophysiology of Cushing's syndrome:
Your Answer: Catecholamine-secreting tumour
Correct Answer: Glucocorticoid excess
Explanation:Cushing’s syndrome is the name given to the clinical symptoms and signs induced by chronic glucocorticoid excess.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 23
Incorrect
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The following statements are not true of the flexor digiti minimi brevis, except?
Your Answer: It forms part of the thenar eminence
Correct Answer: It is situated on the radial border of abductor digiti minimi
Explanation:Flexor digiti minimi brevis muscle is located on the ulnar side of the palm, lying on the radial border of the abductor digiti minimi. Together with the abductor digiti minimi and opponens digiti minimi muscles, it forms the hypothenar eminence. The muscle is situated inferior and lateral to adductor digiti minimi muscle and superior and medial to opponens digiti minimi muscle. The proximal parts of flexor digiti minimi brevis and abductor digiti minimi muscles form a gap through which deep branches of the ulnar artery and ulnar nerve pass.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 24
Incorrect
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A 4-year-old girl is rushed to the Emergency Department by her grandparents after swallowing some of her grandfather's Warfarin tablets. On further questioning, it turns out that she took 5 of his 3 mg tablets which he needs to take due to a history of atrial fibrillation. The child appears healthy well-oriented in time, place and person, and has normal vitals. What is the threshold dose of Warfarin that needs to be ingested for there to be a risk of anticoagulation?
Your Answer: 1.0 mg/kg
Correct Answer: 0.5 mg/kg
Explanation:The clinical effects of Warfarin occur after a dose of greater than 0.5 mg/kg, and they will be observable 8-10 hours after consumption of the drug. The antidote used for Warfarin is Vitamin K.1. In low-risk cases with no apparent bleeding: an oral dose of 10 mg vitamin K2. If there is clinically significant bleedingan intravenous dose of 250-300 mcg/kgActivated charcoal: in cases of warfarin ingestionbinds to it and reduces the absorption of warfarin the ingestion must have occurred within the last hourThere is, however, rarely a need for the use of activated charcoal because vitamin K is such as safe and effective antidote. Clotting studies, including an INR, can be performed, but small children who have ingested warfarin do not require INRs or follow up if they have been treated with 10 mg vitamin K. This dose of vitamin will completely reverse the anticoagulative effects of warfarin.Perform INR if any of the following are present:1. Delayed presentation (>6 hours)2. Patients with symptoms or signs of anticoagulation3. Possible massive ingestion
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 25
Correct
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A 30-year-old patient has a mild exacerbation of his asthma. His steroid inhaler ran out a couple of weeks ago, and he has not replaced it.Which of these statements describes the mechanism of action of corticosteroids in asthma?
Your Answer: Reduction of bronchial inflammation
Explanation:Inhaled corticosteroids suppresses airway inflammation seen in asthma by downregulating pro-inflammatory proteins.They also appear to reverse components of asthma-induced structural changes (airway remodelling), including increased vascularity of the bronchial wall.Corticosteroids reduces the number of inflammatory cells (eosinophils, T lymphocytes, mast cells, and dendritic cells) in the airways.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 26
Correct
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A 40-year-old male presents to your clinic complaining of a cough with bloody sputum for the past three months. He has also had fever, night sweats, and has noticed some weight loss over the past three months.Which ONE of the following statements regarding this disease is correct?
Your Answer: It can be diagnosed using the Ziehl-Neelson stain
Explanation:Tuberculosis is an infection caused by the microorganism Mycobacterium tuberculosis. TB can affect any organ system in the body, but it most commonly affects the lungs, followed by the lymph nodes. Option Tuberculosis is spread by the faecal-oral route: It is spread by inhalation of droplet nuclei. There are different methods to diagnose a tuberculosis infection. 1) Direct Microscopy: The organisms are visualised using Ziehl-Neelsen or Auramine staining. This is the quickest method to establish a diagnosis and start treatment.2) Culture: M. tuberculosis can be grown on Lowenstein-Jensen or Ogawa mediums, but it can take up to 8 weeks; therefore, ZN staining is also performed to start treatment immediately. Option There are several types of vaccine currently available: The BCG vaccine is the only vaccine approved to prevent TB and is administered at birth. Option Miliary tuberculosis refers to tuberculosis that affects the spine: Miliary tuberculosis refers to a tuberculosis infection disseminated throughout the body’s organ systems via the blood or lymphatics. Pott’s disease is extrapulmonary TB that affects the spine. It usually affects the lower thoracic and upper lumbar regions.Option A Ghon focus typically appears at the apex of a lung: The Ghon focus is a primary sign of TB that forms in the lung of previously unaffected patients. It typically occurs in the mid or lower zones of the lung.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 27
Correct
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An ambulance transports a 23-year-old woman who has taken a witnessed overdose of her mother's diazepam tablets. She has no significant medical history and does not take any medications on a regular basis.In this case, what is the SINGLE MOST APPROPRIATE FIRST DRUG TREATMENT?
Your Answer: Flumazenil IV 200 μg
Explanation:Flumazenil is a benzodiazepine antagonist that can be helpful in some overdose situations. It works quickly (in less than a minute), but the effects are fleeting, lasting less than an hour. The dose is 200 micrograms every 1-2 minutes with a maximum dose of 3 milligrams per hour.Flumazenil should be avoided by patients who are addicted to benzodiazepines or who take tricyclic antidepressants because it can cause withdrawal symptoms. It can cause seizures or cardiac arrest in these situations.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 28
Correct
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A dermatological examination on a patient presenting with a lump shows a solid, well circumscribed, lump measuring 0.8 cm in diameter.Which one of these best describes the lump you have found on examination?
Your Answer: Nodule
Explanation:A nodule is a solid, well circumscribed, raised area that lies in or under the skin and measures greater than 0.5 cm in diameter. They are usually painless.A vesicle is a visible collection of fluid measuring less than 0.5 cm in diameter. A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.A papule is a solid, well circumscribed, skin elevation measuring less than 0.5 cm in diameter.A plaque is a palpable skin lesion that is elevated and measures >1cm in diameter
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 29
Correct
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A 45-year-old man, a known case of epilepsy, visits his neurologist with complaints of red, swollen gums.Which of the following medications is most likely responsible for his symptoms?
Your Answer: Phenytoin
Explanation:Phenytoin is a commonly used antiepileptic drug. A well-recognized side-effect of phenytoin is gingival enlargement and occurs in about 50% of patients receiving phenytoin. It is believed that reduced folate levels may cause this, and evidence suggests that folic acid supplementation may help prevent this in patients starting phenytoin. As evidence suggests, drug-induced gingival enlargement may also improve by substituting with other anticonvulsant drugs and reinforcing a good oral hygiene regimen. Surgical excision of hyperplastic gingiva is often necessary to correct the aesthetic and functional impairment associated with this condition to manage it successfully.Phenytoin is also the only anticonvulsant therapy associated with the development of Dupuytren’s contracture.Other side effects are:1. Ataxia2. Drug-induced lupus3. Hirsutism4. Pruritic rash5. Megaloblastic anaemia6. Nystagmus
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 30
Correct
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Which of the following side effects has limited the use of etomidate as an intravenous induction agent:
Your Answer: Adrenocortical suppression
Explanation:Etomidate causes the least cardiovascular depression of the intravenous induction agents, with only a small reduction in the cardiac output and blood pressure. In the past, etomidate was widely used to induce anaesthesia in the shocked, elderly or cardiovascularly unstable patient. However, more recently it has become less popular as a single induction dose blocks the normal stress-induced increase in adrenal cortisol production for 4 – 8 hours, and up to 24 hours in elderly and debilitated patients. Although no increase in mortality has been identified following a single dose during induction of anaesthesia, the use of etomidate has declined due to a perceived potential morbidity.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 31
Correct
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You need to give your patient antibiotics, so you call microbiology for some advice.Of the following antibacterial drugs, which of them is a protein synthesis inhibitor?
Your Answer: Erythromycin
Explanation:Bacteriostatic antibiotics include erythromycin and other macrolides. They work by attaching to the bacterial ribosome’s 50S subunit, preventing translocation and, as a result, inhibit protein synthesis. Macrolide antibiotics are actively concentrated inside leukocytes and delivered into the infection site as a result.Action Mechanisms- Examples:Cell wall production is inhibitedVancomycinVancomycinCephalosporinsThe function of the cell membrane is disrupted NystatinPolymyxinsAmphotericin B Inhibition of protein synthesisChloramphenicolMacrolidesAminoglycosidesTetracyclinesNucleic acid synthesis inhibitionQuinolonesTrimethoprimRifampicin5-nitroimidazolesSulphonamidesAnti-metabolic activityIsoniazid
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 32
Incorrect
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A lesion to which part of the optic radiation will result in contralateral homonymous inferior quadrantanopia?
Your Answer: Left parietal lobe
Correct Answer: Right parietal lobe
Explanation:A visual loss in the lower left quadrant in both visual fields is an indication of an inferior homonymous. This is due to a lesion of the superior fibres of the optic radiation in the parietal lobe on the contralateral side of the visual pathway.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 33
Correct
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Urine flow rate = 2 ml/minUrine concentration of creatinine = 18 mg/ml Plasma concentration of creatinine = 0.25 mg/ml What is the estimated glomerular filtration rate (eGFR)?
Your Answer: 144 ml/min
Explanation:GFR can be estimated by:GFR = UCr x V / PCrWhere:UCr = urine concentration of creatininePCr = plasma concentration of creatinineV = rate of urine flowIn this case GFR = (18 x 2) / 0.25 = 144 ml/minNote: Creatinine is used to estimate GFR because it is an organic base naturally produced by muscle breakdown, it is freely filtered at the glomerulus, it is not reabsorbed from the nephron, it is not produced by the kidney, it is not toxic, and it doesn’t alter GFR.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 34
Correct
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Digoxin is predominantly used for which of the following:
Your Answer: Rate control in persistent and permanent atrial fibrillation
Explanation:Digoxin is most useful for controlling the ventricular response in persistent and permanent atrial fibrillation and atrial flutter. Digoxin is usually only effective for controlling the ventricular rate at rest, and should therefore only be used as monotherapy in predominantly sedentary patients with non-paroxysmal atrial fibrillation. It is now rarely used for rapid control of heart rate, as even with intravenous administration, response may take many hours. Digoxin is reserved for patients with worsening or severe heart failure due to left ventricular systolic dysfunction refractory to combination therapy with first-line agents. Digoxin is contraindicated in supraventricular arrhythmias associated with accessory conduction pathways e.g. Wolff-Parkinson-White syndrome.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 35
Incorrect
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Carbamazepine is indicated for all of the following EXCEPT for:
Your Answer: Generalised tonic-clonic seizures
Correct Answer: Myoclonic seizures
Explanation:Carbamazepine is a drug of choice for simple and complex focal seizures and is a first-line treatment option for generalised tonic-clonic seizures. It is also used in trigeminal neuralgia and diabetic neuropathy. Carbamazepine may exacerbate tonic, atonic, myoclonic and absence seizures and is therefore not recommended if these seizures are present.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 36
Correct
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Which of the following immunoglobulins is most important for mast cell degranulation:
Your Answer: IgE
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 37
Incorrect
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An elderly man with chronic heart and lung disease develops Legionnaires' Disease. By what route was the infection most likely to have been acquired:
Your Answer: Using snuff that contained spores
Correct Answer: Inhalation of aerosolised contaminated water
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.The clinical features of the pneumonic form of Legionnaires’ disease include:Mild flu-like prodrome for 1-3 daysCough (usually non-productive and occurs in approximately 90%)Pleuritic chest painHaemoptysisHeadacheNausea, vomiting and diarrhoeaAnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 38
Correct
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Regarding bile, which of the following statements is INCORRECT:
Your Answer: The sphincter of Oddi contracts to force bile from the gallbladder into the duodenum.
Explanation:Bile is secreted by hepatocytes. It is isotonic and resembles plasma ionically. This fraction of bile is called the bile acid-dependent fraction. As it passes along the bile duct, the bile is modified by epithelial cells lining the duct by the addition of water and bicarbonate ions; this fraction is called the bile acid-independent fraction. Overall, the liver can produce 500 – 1000 mL of bile per day. The bile is either discharged directly into the duodenum or stored in the gallbladder. The bile acid-independent fraction is made at the time it is required i.e. during digestion of chyme. The bile acid-dependent fraction is made when the bile salts are returned from the GI tract to the liver, and is then stored in the gallbladder until needed. The gallbladder not only stores bile but concentrates it by removing non-essential solutes and water, leaving bile acids and pigments, mainly by active transport of Na+into the intercellular spaces of the lining cells which, in turn, draws in water, HCO3-and Cl-from the bile and into the extracellular fluid. Within a few minutes of a meal, particularly when fatty foods have been consumed, the gallbladder contracts and releases bile into the bile duct. The sphincter of Oddi is relaxed, allowing the bile to pass into the duodenum through the ampulla of Vater.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 39
Correct
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In adult advanced life support, which of the following best describes the correct administration of adrenaline for a non-shockable rhythm:
Your Answer: Give 1 mg of adrenaline as soon as intravenous access is achieved and every 3 - 5 minutes thereafter
Explanation:IV adrenaline 1 mg (10 mL of 1:10,000 solution) should be given after 3 shocks and every 3 – 5 minutes/after alternate shocks thereafter.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 40
Incorrect
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Giemsa-stained blood film microscopy is typically used for the diagnosis of which of the following:
Your Answer: Syphilis
Correct Answer: Malaria
Explanation:Giemsa-stained blood film microscopy can be used to identify malarial parasites.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 41
Correct
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The interquartile range (IQ) is often displayed using which of the following:
Your Answer: Box and whisker plot
Explanation:A boxplot is a vertical or horizontal rectangle used to display the interquartile range, with the ends of the rectangle corresponding to the upper and lower quartiles of the data values. The box contains 50% of the data values. A line drawn through the rectangle corresponds to the median value. Whiskers, starting at the ends of the rectangle usually indicate the minimum and maximum values, therefore the entire box and whisker plot represents the range. Any outliers can be plotted independent of the box and whisker plot.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 42
Correct
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A 25 year old woman who is a known diabetic is brought to the ED with diabetic ketoacidosis. She promptly received an insulin infusion. Which of the following are expected to increase upon infusion of insulin?
Your Answer: Blood pH
Explanation:Ketoacidosis is characterized by hyperglycaemia, glycosuria, hyperkalaemia, and metabolic acidosis with respiratory compensation. An insulin infusion would be able to address these by lowering blood glucose through increased insulin-mediated cellular uptake, lowering urine glucose concentration as cellular glucose uptake is increased, decreasing K+ in her blood by shifting it into cells, and increasing blood ph by addressing the metabolic acidosis. The metabolic acidosis is addressed by the reduction of ketoacids production thereby returning her blood ph to normal and reducing the need for compensatory hyperventilation.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 43
Correct
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A blood test of a 7-year-old child with a 6-day history of bloody diarrhoea reveals a low platelet count, anaemia, and impaired kidney function. What bacteria is suspected of causing such a condition?
Your Answer: Escherichia coli
Explanation:Escherichia coli produces shiga toxin that causes diarrhoea, hemorrhagic colitis, and haemolytic uremic syndrome. Haemolytic uremic syndrome is characterized by anaemia, thrombocytopenia, and acute renal failure. Transmission of E. coli is possible after consuming contaminated, undercooked drinks and foods. E. coli enters the body via the faecal-oral pathway.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 44
Incorrect
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A 23-year-old male presents to his family physician with the complaint of repeated episodes of abdominal pain and the passage of dark coloured urine every morning. He also reports increasing fatigue over the past several months. On examination, there are raised, painful red nodules over the skin of the back. Laboratory workup shows haemolytic anaemia, leukopenia and thrombocytopenia. Which one of the following disorders is this patient most likely to have?
Your Answer: Acute lymphoblastic leukaemia
Correct Answer: Paroxysmal nocturnal haemoglobinuria
Explanation:Paroxysmal nocturnal haemoglobinuria is an acquired genetic disorder that causes a decrease in red blood cells due to a membrane defect that allows increased complement binding to RBCs, causing haemolysis. Patients complain of dark-coloured urine first in the morning due to haemoglobinuria secondary to lysis of red blood cells overnight. Thrombosis occurs, which affects hepatic, abdominal, cerebral and subdermal veins. Thrombosis of hepatic veins can lead to Budd-Chiari syndrome, thrombosis of subdermal veins can lead to painful nodules on the skin, and thrombosis of cerebral vessels can lead to stroke. The presence of dark urine in the morning only and at no other time differentiates this condition from other conditions.Multiple myeloma would present with bone pain, signs of radiculopathy if there were nerve root compression and a history of repeated infections. Patients with Non-Hodgkin Lymphoma would complain of enlarged lymph nodes, fatigue, fever, weight loss and a history of repeated infections. Acute lymphoblastic leukaemia presents more commonly in children than in adults. The patient would complain of bone pain, and on examination, there would be hepatosplenomegaly.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 45
Correct
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In adults, there are normally how many teeth:
Your Answer: 32
Explanation:In adults, there are 32 teeth, 16 in the upper jaw and 16 in the lower jaw. On each side in both upper and lower arches, there are two incisors, one canine, two premolars and three molar teeth.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 46
Correct
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Approximately what percentage of filtered bicarbonate is reabsorbed in the proximal tubule:
Your Answer: 0.8
Explanation:Bicarbonate is freely filtered at the glomerulus. Less than 0.1% of filtered bicarbonate is normally excreted in the urine (if plasma [HCO3-] increases, maximum tubular transport is exceeded and some HCO3-is excreted in urine). About 80% of bicarbonate is reabsorbed in the proximal tubule. For each H+secreted into the lumen, one Na+and one HCO3-are reabsorbed into the plasma. H+is recycled so there is little net secretion of H+at this stage. A further 10 – 15% of HCO3-is similarly reabsorbed in the thick ascending limb of the loop of Henle. In the early distal tubule, H+secretion is predominantly by Na+/H+exchange but more distally, the Na+gradient is insufficient so secretion is via H+ATPase and H+/K+ATPase in intercalated cells, which contain plentiful carbonic acid. As secreted H+is derived from CO2, new HCO3-is formed and returns to the blood.H+secretion is proportional to intracellular [H+] which itself is related to extracellular pH. A fall in blood pH will therefore stimulate renal H+secretion. In the proximal tubule secretion of H+serves to reclaim bicarbonate from glomerular filtrate so it is not lost, but in the distal nephron, secretion leads to net acid excretion and generation of new bicarbonate.
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This question is part of the following fields:
- Physiology
- Renal
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Question 47
Correct
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A 28-year-old patient who has been in a car accident needs to be intubated using a rapid sequence induction. As an induction agent, you intend to use etomidate.Etomidate works by interacting with which type of receptor?
Your Answer: Gamma-aminobutyric acid (GABA)
Explanation:Etomidate is a carboxylated imidazole derivative with a short half-life that is primarily used to induce anaesthesia.It is thought to modulate fast inhibitory synaptic transmission in the central nervous system by acting on GABA type A receptors.The dose for anaesthesia induction is 0.3 mg/kg. Etomidate takes 10-65 seconds to take effect after an intravenous injection, and it lasts 6-8 minutes. With repeated administration, the effects are non-cumulative.The relative cardiovascular stability of etomidate is noteworthy. During induction, it causes less hypotension than thiopental sodium and propofol. It’s also linked to a quick recovery without the hangover.Etomidate is a strong steroidogenesis inhibitor. The drug inhibits the enzymes responsible for adrenal 11 beta-hydroxylase and cholesterol cleavage, resulting in a decrease in cortisol and aldosterone synthesis for up to 24 hours after administration. It should not be used to maintain anaesthesia because of the adrenocortical suppression.Other side effects associated with etomidate use include:Vomiting and nauseaThe injection causes pain (in up to 50 percent )Phlebitis and thrombosis of the veinsHeart block and arrhythmiasHyperventilationApnoea and respiratory depressionIt has the potential to cause both hypo- and hypertension.Critically ill patients have a higher mortality rate.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 48
Incorrect
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Which of the following is NOT a common side effect of amiodarone:
Your Answer: Slate grey skin discolouration
Correct Answer: Blue/green teeth discolouration
Explanation:Common side effects of amiodarone include: Bradycardia, Nausea and vomiting, Thyroid disorders – hypothyroidism and hyperthyroidism, Persistent slate grey skin discoloration, Photosensitivity, Pulmonary toxicity (including pneumonitis and fibrosis), Hepatotoxicity, Corneal microdeposits (sometimes with night glare), Peripheral neuropathy and Sleep disorders.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 49
Incorrect
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In the extrinsic pathway of the coagulation cascade, the tenase complex is:
Your Answer: Factor IXa- VIIa complex
Correct Answer: Factor VIIa-tissue factor complex
Explanation:The extrinsic pathway for initiating the formation of prothrombin activator begins with a traumatized vascular wall or traumatized extravascular tissues that come in contact with the blood. Exposed and activated by vascular injury, with plasma factor VII. The extrinsic tenase complex, factor VIIa-tissue factor complex, activates factor X to factor Xa.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 50
Correct
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A 42-year-old woman with a history of hyposplenism arrives at the Emergency Department sick and feverish. A complete set of bloods, including a peripheral blood film, is organised.On a hyposplenic blood film, which of the following features is LEAST likely to be seen?
Your Answer: Teardrop cells
Explanation:The collection of abnormalities found in these patients is referred to as a hyposplenic film.The following features can be seen on hyposplenic blood films:Howell-Jolly bodiesHeinz’s bodiesTarget cellsRBCs with nuclei on occasionLymphocytosisMacrocytosisAcanthocytesTeardrop cells, also known as dacrocytes, are named for their teardrop-shaped shape. Dacrocytosis is a condition in which a large number of these cells are present. Myelofibrosis and beta thalassemia major both have dacrocytes, but hyposplenism does not.
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This question is part of the following fields:
- Haematology
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
