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  • Question 1 - A 25-year-old male presented to accident and emergency 4 days ago, following an...

    Incorrect

    • A 25-year-old male presented to accident and emergency 4 days ago, following an intentional paracetamol overdose. He had taken 20x 500mg tablets, all at once. He denies any alcohol intake. Blood investigations 4 hours after ingestion showed:Paracetamol: 14 mg/lINR: 1Liver enzymes: No abnormality detectedBilirubin: Mild elevationHe was seen by the mental health team and discharged. The blood investigations were repeated:Bilirubin: Within normal limitsUrea: 21 mmol/lCreatinine: 300 µmol/lWhat is the likely cause of these results?

      Your Answer: Minimal change nephropathy

      Correct Answer: Delayed paracetamol nephrotoxicity

      Explanation:

      The most likely cause for these results is delayed paracetamol nephrotoxicity.The blood investigations of this patient are highly suggestive of acute kidney injury. Paracetamol overdose is well known to cause hepatotoxicity, but not for its delayed nephrotoxicity, especially in significant overdose. Appropriate monitoring of a patient’s blood tests is important.Management:NAC (N-Acetyl cysteine) has a clear role in preventing acetaminophen-induced liver necrosis. Although NAC has not been proven to be harmful to the kidney, its role in patients without hepatoxicity and only isolated renal dysfunction is uncertain.Other options:-There are no features in the history that are suggestive of dehydration and pre-renal AKI presenting in this manner in a 25-year-old would be very unusual.- Minimal change nephropathy typically presents with a nephrotic picture of kidney injury.- Berger’s more commonly presents with isolated haematuria.

    • This question is part of the following fields:

      • Medicine
      • Pharmacology
      121.8
      Seconds

  • Question 2 - In Starling’s law of the heart, the decrease in tension developed by muscle...

    Incorrect

    • In Starling’s law of the heart, the decrease in tension developed by muscle contraction at high degrees of stretch is due to:

      Your Answer: A conformational change in the myosin head at high degrees of stretch.

      Correct Answer: Disruption of myocardial fibers

      Explanation:

      Starling law states that the force of contraction is directly proportional to the preload. When the heart muscle is stretched beyond its limit the tension that is developed decreases, this is not due to loss of formation of effective myosin and actin cross bridges. The heart muscles despite being fully stretched is never stretched to this point. The reason for this decreased tension is physical disruption of the myocardial fibers.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      51.2
      Seconds

  • Question 3 - Which of the following is true with AV nodal delay? ...

    Incorrect

    • Which of the following is true with AV nodal delay?

      Your Answer: The delay is about 0.01s

      Correct Answer: Shortened by sympathetic stimulation

      Explanation:

      AV nodal delay Is about 0.1s before the action potential spreads to the ventricles. It is shortened by stimulation of the sympathetic nervous system and lengthened by stimulation of the parasympathetic system.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      18.2
      Seconds

  • Question 4 - Although variable, branches of which artery most often supply the SA and AV...

    Incorrect

    • Although variable, branches of which artery most often supply the SA and AV nodes?

      Your Answer:

      Correct Answer: Right coronary artery

      Explanation:

      The RCA (right coronary artery) supplies the SA and the AV nodes along with the postero-basal wall of the left ventricle, posterior one third of the inferior vena cava, right ventricle and the posteromedial papillary muscle in the left ventricle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 5 - During which phase of the cell cycle does transcription of DNA synthesis molecules...

    Incorrect

    • During which phase of the cell cycle does transcription of DNA synthesis molecules occur?

      Your Answer:

      Correct Answer: S

      Explanation:

      DNA synthesis occurs in the S phase of the cell cycle. In the G1 phase the cell prepares to divide. In G2 the cellular organelles divide and in the M phase mitosis occur. In the G0 phase the cell becomes quiescent and does not divide further.

      Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is made up of mitosis and cytokinesis and leads to the formation of two daughter cells.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 6 - A 72 year old retired fisherman presents with weakness of shoulders and hips...

    Incorrect

    • A 72 year old retired fisherman presents with weakness of shoulders and hips over the last four months. Finger flexion is also weak but the extension is normal. There has been some difficulty swallowing liquids. Past medical history is not significant except for sexually transmitted disease that he caught some 40 years ago in South Pacific and got treated with antibiotics. He smokes and drinks one or two tots of rum at the weekend. Creatine kinase level is 125. Which of the following investigations is most significant in establishing a diagnosis?

      Your Answer:

      Correct Answer: Muscle biopsy with electron microscopy

      Explanation:

      Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon, but have been reported in some people. The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited. Elevated creatine kinase (CK) levels in the blood (at most ,10 times normal) are typical in IBM. Muscle biopsy may display several common findings including; inflammatory cells invading muscle cells, vacuolar degeneration, inclusions or plaques of abnormal proteins.

    • This question is part of the following fields:

      • Connective Tissue
      • Medicine
      0
      Seconds

  • Question 7 - What landmark divides the frontal and parietal lobes? ...

    Incorrect

    • What landmark divides the frontal and parietal lobes?

      Your Answer:

      Correct Answer: Central sulcus

      Explanation:

      The central sulcus divides the frontal lobe from the parietal lobe. It contains the motor cells for the movement function of the body.

    • This question is part of the following fields:

      • Medicine
      • Neurology
      0
      Seconds

  • Question 8 - Which of the following is responsible for transporting both glucose and fructose into...

    Incorrect

    • Which of the following is responsible for transporting both glucose and fructose into the interstitium?

      Your Answer:

      Correct Answer: GLUT 2

      Explanation:

      Absorption of glucose involves transport from the intestinal lumen, across the epithelium and into blood. The transporter that carries glucose and galactose into the enterocyte is the sodium-dependent hexose transporter, known as SGLT1. As the name indicates, this molecule transports both glucose and sodium ions into the cell. Once absorbed into the enterocyte, glucose must be exported from the cell into blood. Sodium is rapidly shuttled out in exchange for potassium by Na+/K+ ATPase pumps on the basolateral membrane, and that process maintains the electrochemical gradient across the epithelium. Glucose, galactose and fructose are transported out of the enterocyte into the interstitium and in turn into the blood through another hexose transporter (called GLUT-2) in the basolateral membrane. These monosaccharides then diffuse down a concentration gradient into capillary blood.

    • This question is part of the following fields:

      • Gastrointestinal
      • Medicine
      0
      Seconds

  • Question 9 - How does the proximal convoluted tubule excrete H+? ...

    Incorrect

    • How does the proximal convoluted tubule excrete H+?

      Your Answer:

      Correct Answer: Via Na+/H+ antiporter.

      Explanation:

      H+ secretion from cells across the luminal membrane is mostly in exchange for Na+ ions, and to a small extent, through a proton ATPase. Secreted H+ react with filtered HC03- to form H2CO3.

    • This question is part of the following fields:

      • Medicine
      • Renal
      0
      Seconds

  • Question 10 - Cholinergic vagal supply to the SA and AV nodes results in slowing of...

    Incorrect

    • Cholinergic vagal supply to the SA and AV nodes results in slowing of the heart rate via:

      Your Answer:

      Correct Answer: M2 muscarinic receptors

      Explanation:

      M2 muscarinic receptors are the receptors for the parasympathetic system to the SA and the AV node.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 11 - Which of the following initiates migrating motor complex ...

    Incorrect

    • Which of the following initiates migrating motor complex

      Your Answer:

      Correct Answer: Motilin

      Explanation:

      Migrating motor complexes (MMC) are thought to be partially regulated by motilin, which is initiated in the stomach as a response to vagal stimulation, and does not directly depend on extrinsic nerves.

    • This question is part of the following fields:

      • Gastrointestinal
      • Medicine
      0
      Seconds

  • Question 12 - There is normally an inverse relationship between the hepatic artery and portal venous...

    Incorrect

    • There is normally an inverse relationship between the hepatic artery and portal venous blood flow. This is maintained by:

      Your Answer:

      Correct Answer: All of the options are correct

      Explanation:

      There is an inverse relationship between the blood flow of the hepatic artery and portal vein. It is maintained by several factors such as chemicals like adenosine, neurohumoral substances, the morphology of the hepatic portal system (especially the ability of hepatic sinusoids to collapse) and myogenic control which causes vasoconstriction or vasodilation.

    • This question is part of the following fields:

      • Gastrointestinal
      • Medicine
      0
      Seconds

  • Question 13 - The celiac trunk consists of which arteries? ...

    Incorrect

    • The celiac trunk consists of which arteries?

      Your Answer:

      Correct Answer: Left gastric, common hepatic, splenic

      Explanation:

      The celiac trunk is the first major branch of the abdominal aorta. It is 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12). There are three main divisions of the celiac artery:- left gastric artery- common hepatic artery- splenic artery

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 14 - The following determines the strength of contraction ...

    Incorrect

    • The following determines the strength of contraction

      Your Answer:

      Correct Answer: Plateau phase

      Explanation:

      The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (or refractory) phase in myocyte action potential prevents early reactivation of the myocytes and directly determines the strength of contraction

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 15 - Myocyte action potentials – Choose the false statement: ...

    Incorrect

    • Myocyte action potentials – Choose the false statement:

      Your Answer:

      Correct Answer: Repolarisation is due to net k+ influx

      Explanation:

      Final repolarization (phase 3) to the resting membrane potential (phase 4) is due to closure of the Ca2+ channels and a slow, delayed increase of K+ efflux through various types of K+ channels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 16 - Which one of the following nerve fibers has the fastest conduction velocity? ...

    Incorrect

    • Which one of the following nerve fibers has the fastest conduction velocity?

      Your Answer:

      Correct Answer: α fiber

      Explanation:

      α nerve fibers are characterized by being highly myelinated, which confers them with fast conduction properties. They innervate extrafusal skeletal muscle fibers, and their conduction velocity is between 80-120 m/s.

    • This question is part of the following fields:

      • Medicine
      • Neurology
      0
      Seconds

  • Question 17 - Which of the following does not lower ventricular rate in atrial fibrillation? ...

    Incorrect

    • Which of the following does not lower ventricular rate in atrial fibrillation?

      Your Answer:

      Correct Answer: Adrenaline

      Explanation:

      Adrenaline is a sympathetic neurotransmitter which increases the heart rate. During atrial fibrillation the atria is contracting at more than 200 beats/min. Acetylcholine is a parasympathetic neurotransmitter decreasing the heart rate. Digital also depresses the conduction at the AV conduction. Vagal discharge and occulocardiac reflux decrease the heart rate and convert the tachycardia into normal sinus rhythm.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 18 - From which of the following can niacin be synthesized in humans ...

    Incorrect

    • From which of the following can niacin be synthesized in humans

      Your Answer:

      Correct Answer: Tryptophan

      Explanation:

      Niacin, is also known as vitamin B3. The liver can synthesize niacin from the essential amino acid tryptophan, requiring 60 mg of tryptophan to make one mg of niacin.

    • This question is part of the following fields:

      • Haematology
      • Medicine
      0
      Seconds

  • Question 19 - The reflex responses activated by cold are controlled by which area? ...

    Incorrect

    • The reflex responses activated by cold are controlled by which area?

      Your Answer:

      Correct Answer: Posterior hypothalamus

      Explanation:

      The posterior nucleus of the hypothalamus is responsible for thermoregulation and thermogenesis. Studies have shown that the neurons in the posterior hypothalamus which mediate the reflex of shivering are sensitive to temperature; damage to this nucleus produces hypothermia.

    • This question is part of the following fields:

      • Endocrinology
      • Medicine
      0
      Seconds

  • Question 20 - Immortality can result from over expression of which enzyme? ...

    Incorrect

    • Immortality can result from over expression of which enzyme?

      Your Answer:

      Correct Answer: Telomerase

      Explanation:

      Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 21 - Cells responsible for completely renewing the epithelium of the intestine are located: ...

    Incorrect

    • Cells responsible for completely renewing the epithelium of the intestine are located:

      Your Answer:

      Correct Answer: At the base of the crypts

      Explanation:

      Epithelial cells are renewed every 4-5 days through a process of renewal and migration. Renewal relies on proliferative cells or stem cells that reside at the crypt base of the intestinal glands. Crypts are epithelial invasions into the underlying connective tissue.

    • This question is part of the following fields:

      • Gastrointestinal
      • Medicine
      0
      Seconds

  • Question 22 - The SA and AV nodes are usually supplied by which artery? ...

    Incorrect

    • The SA and AV nodes are usually supplied by which artery?

      Your Answer:

      Correct Answer: Right coronary artery

      Explanation:

      The right coronary artery supplies the right atrium, right ventricle, SA and AV nodes.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 23 - Phosphate absorption in the proximal tubules is via which transporting molecule? ...

    Incorrect

    • Phosphate absorption in the proximal tubules is via which transporting molecule?

      Your Answer:

      Correct Answer: Na/Pi co transporter

      Explanation:

      Sodium/phosphate cotransporters are located in the renal proximal tubular brush border, and are the key elements in proximal tubular phosphate reabsorption and phosphate homeostasis.

    • This question is part of the following fields:

      • Endocrinology
      • Medicine
      0
      Seconds

  • Question 24 - Regarding cardiac muscle contractility, the afterload refers to: ...

    Incorrect

    • Regarding cardiac muscle contractility, the afterload refers to:

      Your Answer:

      Correct Answer: The resistance against which blood is expected

      Explanation:

      The afterload for the left ventricle is the aortic pressure. Hence it is this pressure that offers resistance against which the blood is to be expelled from the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 25 - What is the function of the macula densa, located in the wall of...

    Incorrect

    • What is the function of the macula densa, located in the wall of the thick ascending limb?

      Your Answer:

      Correct Answer: Tubuloglomerular feedback.

      Explanation:

      Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal. Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signalling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level.

    • This question is part of the following fields:

      • Medicine
      • Renal
      0
      Seconds

  • Question 26 - Which mechanism of action does Trimethoprim use? ...

    Incorrect

    • Which mechanism of action does Trimethoprim use?

      Your Answer:

      Correct Answer: Inhibit Folic Acid metabolism

      Explanation:

      Trimethoprim binds to dihydrofolate reductase and inhibits the reduction of dihydrofolic acid (DHF) to tetrahydrofolic acid (THF). THF is an essential precursor in the thymidine synthesis pathway and interference with this pathway inhibits bacterial DNA synthesis.

    • This question is part of the following fields:

      • Infectious Diseases
      • Medicine
      0
      Seconds

  • Question 27 - Which of the following cells are attracted to the surface of endothelium by...

    Incorrect

    • Which of the following cells are attracted to the surface of endothelium by selectins?

      Your Answer:

      Correct Answer: Neutrophils

      Explanation:

      Selectins are expressed on the surface of the endothelium. P selectins are released from weibel-palade bodies and E selectins are induced by cytokines (TNF and IL-1). They bind to receptors on the neutrophils called saiyl lewis X.

    • This question is part of the following fields:

      • Immunology
      • Medicine
      0
      Seconds

  • Question 28 - An 80-year-old woman with advanced COPD has been admitted to the medicine ward...

    Incorrect

    • An 80-year-old woman with advanced COPD has been admitted to the medicine ward in an unconscious state. She appears to have an acute lower respiratory tract infection. After consulting with an anaesthesiologist it was concluded that she was not a candidate for intensive care unit admission and thus, a decision was made to start the patient on doxapram therapy. Which of the following best fits the characteristics of doxapram?

      Your Answer:

      Correct Answer: It is contraindicated in hyperthyroidism

      Explanation:

      The two statements that fit the characteristics of doxapram are, epilepsy is a contraindication for doxapram use and concurrent use with theophylline may increase agitation.Doxapram is a central respiratory stimulant. In clinical practice, doxapram is usually used for patients who have an acute exacerbation of chronic obstructive pulmonary disease (COPD) who are unsuitable for admission to the intensive therapy unit for ventilatory support. Doxapram infusion may buy an extra 24 h to allow for recovery.Contraindications include: ischaemic heart disease, epilepsy, cerebral oedema, acute stroke, asthma, hypertension, hyperthyroidism, and pheochromocytoma. The infusion may worsen agitation and dyspnoea and lead to hypertension, nausea, vomiting and urinary retention.Drug interactions:Concomitant administration of doxapram and aminophylline (theophylline) can cause increased skeletal muscle activity, agitation, and hyperactivity.

    • This question is part of the following fields:

      • Medicine
      • Pharmacology
      0
      Seconds

  • Question 29 - The mitochondrial chromosome is a circular DNA molecule. They encode for proteins needed...

    Incorrect

    • The mitochondrial chromosome is a circular DNA molecule. They encode for proteins needed for ATP production. These proteins are also essential for:

      Your Answer:

      Correct Answer: Apoptotic cell death

      Explanation:

      The intrinsic pathway or the mitochondrial pathway of apoptosis is activated due to the loss of BCL-2 and other antiapoptotic proteins. This loss results in the increased membrane permeability and release of cytochrome C which activates caspases downstream resulting in apoptosis.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 30 - After exercise, O2 debt repay may take up to: ...

    Incorrect

    • After exercise, O2 debt repay may take up to:

      Your Answer:

      Correct Answer: 90 min

      Explanation:

      Physical activity or exercise requires oxygen for production of ATP or energy via aerobic pathways of energy production. When the amount of oxygen that reaches muscles depletes, cells start producing energy anaerobically by partial breakdown of glucose resulting in lactic acid. Lactic acid should be removed from cells as it causes muscle fatigue. Oxygen is needed to oxidize lactic acid in to carbon dioxide and water and this need is known as oxygen debt. The existence of an oxygen debt explains why we continue to breathe deeply and quickly for a while after exercise. This may take up from 60 – 90 mins.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      0
      Seconds

  • Question 31 - In the menstrual cycle, ovulation is triggered by: ...

    Incorrect

    • In the menstrual cycle, ovulation is triggered by:

      Your Answer:

      Correct Answer: A pituitary LH surge due to the positive feedback effect of circulating oestrogens

      Explanation:

      FSH and LH are secreted to start the development of a follicle at the start of each menstrual cycle. A surge in oestrogen causes a positive feedback in the LH cells of the pituitary; this causes ovulation.

    • This question is part of the following fields:

      • Endocrinology
      • Medicine
      0
      Seconds

  • Question 32 - A 51-year-old real estate agent takes hydrocortisone 20mg in the mornings and 5mg...

    Incorrect

    • A 51-year-old real estate agent takes hydrocortisone 20mg in the mornings and 5mg at night for Addison’s disease. The endocrinology consultant would like her to take prednisolone instead. What dose of prednisolone should be started?

      Your Answer:

      Correct Answer: 7 mg

      Explanation:

      1mg Prednisolone = 4mg hydrocortisone, so the actual equivalent daily dose is 7mg.

    • This question is part of the following fields:

      • Medicine
      • Pharmacology
      0
      Seconds

  • Question 33 - Intermediate filaments achieve cell to cell contact via: ...

    Incorrect

    • Intermediate filaments achieve cell to cell contact via:

      Your Answer:

      Correct Answer: Desmosomes

      Explanation:

      At the plasma membrane, some keratins interact with desmosomes (cell-cell adhesion) and hemidesmosomes (cell-matrix adhesion) via adapter proteins.

    • This question is part of the following fields:

      • Cell Biology
      • Medicine
      0
      Seconds

  • Question 34 - Where is angiotensinogen produced? ...

    Incorrect

    • Where is angiotensinogen produced?

      Your Answer:

      Correct Answer: Liver

      Explanation:

      Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex. Aldosterone promotes sodium retention in the distal nephron, in the kidney, which also drives blood pressure up. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver.

    • This question is part of the following fields:

      • Medicine
      • Renal
      0
      Seconds

  • Question 35 - The enzyme that catalyses the final step in glycogen synthesis is: ...

    Incorrect

    • The enzyme that catalyses the final step in glycogen synthesis is:

      Your Answer:

      Correct Answer: Glycogen synthase

      Explanation:

      Glycogen synthase is a key enzyme in glycogenesis, the conversion of glucose into glycogen. This enzyme combines excess glucose residues one by one into a polymeric chain for storage as glycogen.

    • This question is part of the following fields:

      • Medicine
      • Metabolism
      0
      Seconds

  • Question 36 - B1 adrenergic stimulation produces: ...

    Incorrect

    • B1 adrenergic stimulation produces:

      Your Answer:

      Correct Answer: Increase in calcium cytosolic concentration

      Explanation:

      Norepinephrine secreted by the sympathetic endings binds to B1 receptors, and the resulting increase in intracellular cAMP facilitates the opening of L channels, increasing Ica and the rapidity of the depolarization phase of the impulse and activates PKA which leads to phosphorylation of the voltage-gated Ca2+ channels, causing them to spend more time in the open state.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 37 - Where is Müllerian inhibiting substance (MIS) secreted? ...

    Incorrect

    • Where is Müllerian inhibiting substance (MIS) secreted?

      Your Answer:

      Correct Answer: Sertoli cells

      Explanation:

      Müllerian inhibiting substance, also known as Anti-Müllerian hormone (AMH) or Müllerian-inhibiting hormone (MIH) is a glycoprotein hormone which prevents the development of the Müllerian ducts into the uterus. Its production by Sertoli cells continues during childhood in males and decreases after puberty.

    • This question is part of the following fields:

      • Endocrinology
      • Medicine
      0
      Seconds

  • Question 38 - Which of the following portocaval anastomoses can cause problems in preterm infants? ...

    Incorrect

    • Which of the following portocaval anastomoses can cause problems in preterm infants?

      Your Answer:

      Correct Answer: Patent ductus venosus.

      Explanation:

      The ductus venosus is open at the time of the birth and closes during the first week of life in most full-term neonates; however, it may take much longer to close in pre-term neonates. After it closes, the remnant is known as ligamentum venosum. If the ductus venosus fails to occlude after birth, it remains patent (open), and the individual is said to have a patent ductus venosus and thus an intrahepatic portosystemic shunt (PSS).

    • This question is part of the following fields:

      • Hepatobiliary
      • Medicine
      0
      Seconds

  • Question 39 - Regarding taste threshold and intensity discrimination: ...

    Incorrect

    • Regarding taste threshold and intensity discrimination:

      Your Answer:

      Correct Answer: 30% change in concentration of substance tasted is necessary before an intensity difference can be detected

      Explanation:

      The ability of humans to differentiate differences in intensity of taste is poor. A 30% change in the concentration of the substance being tasted is required before an intensity difference is perceived.

    • This question is part of the following fields:

      • Medicine
      • Neurology
      0
      Seconds

  • Question 40 - Bronchial smooth muscle: ...

    Incorrect

    • Bronchial smooth muscle:

      Your Answer:

      Correct Answer: Tone is increased by cholinergic discharge

      Explanation:

      The lungs are supplied by both the sympathetic and parasympathetic divisions of the autonomic nervous system. The parasympathetic innervation is supplied by the vagus nerve. The parasympathetic nervous system is the dominant neuronal pathway in the control of airway smooth muscle tone. Stimulation of cholinergic nerves causes bronchoconstriction, mucus secretion, and bronchial vasodilation. Sympathetic innervation is supplied by the T1 to T5 of the spinal cord and act mainly via beta adrenergic receptors. Stimulation of the sympathetic nervous system causes vasoconstriction and bronchodilation.

    • This question is part of the following fields:

      • Medicine
      • Respiratory
      0
      Seconds

  • Question 41 - Arterioles stemming from the coronary artery can also empty into the heart directly...

    Incorrect

    • Arterioles stemming from the coronary artery can also empty into the heart directly via the:

      Your Answer:

      Correct Answer: Arteriosinusoidal vessels

      Explanation:

      Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers. They include arteriosinusoidal vessels, which connect the arterioles to the heart chambers. The thebesian veins drain the capillaries into the chambers and the arterioluminal vessels drain small arteries directly into the chambers.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 42 - A 30-year-old male with a history of premature cardiovascular disease in the family...

    Incorrect

    • A 30-year-old male with a history of premature cardiovascular disease in the family has come for review of his lab investigations. His fasting cholesterol is 8.4 mmol/l with high-density lipoprotein (HDL) of 1.6 mmol/l. You elect to commence him on atorvastatin 20 mg PO daily.Which of the following best describes the mechanism of action of the statins?

      Your Answer:

      Correct Answer: They inhibit HMG CoA reductase

      Explanation:

      Statins are a selective, competitive inhibitor of hydroxymethylglutaryl-CoA (HMG-CoA) reductase, which is the enzyme responsible for the conversion of HMG-CoA to mevalonate in the cholesterol synthesis pathway.Statins are usually well tolerated with myopathy, rhabdomyolysis, hepatotoxicity, and diabetes mellitus being the most common adverse reactions. This is the rate-limiting step in cholesterol synthesis, that leads to increased hepatic low-density lipoprotein (LDL) receptors and reduced hepatic VLDL synthesis coupled with increased very-low-density lipoprotein (VLDL) clearance.

    • This question is part of the following fields:

      • Medicine
      • Pharmacology
      0
      Seconds

  • Question 43 - Which of the following is a physiological effect of pregnancy on the kidney?...

    Incorrect

    • Which of the following is a physiological effect of pregnancy on the kidney?

      Your Answer:

      Correct Answer: Decreased creatinine

      Explanation:

      A pregnant woman may experience an increase in kidney and ureter size. The glomerular filtration rate (GFR) commonly increases by 50%, returning to normal around 20 weeks postpartum. Plasma sodium does not change because this is offset by the increase in GFR. There is decreased blood urea nitrogen (BUN) and creatinine and potentially glucosuria (due to saturated tubular reabsorption).

    • This question is part of the following fields:

      • Medicine
      • Renal
      0
      Seconds

  • Question 44 - Where is the melanocortin system located? ...

    Incorrect

    • Where is the melanocortin system located?

      Your Answer:

      Correct Answer: Hypothalamus

      Explanation:

      The melanocortin system is a group of hormones which include hormones from the pro-opiomelanocortin (POMC)-expressing neurons, the neuropeptide Y (NPY) and agouti-related peptide (AgRP)-co-expressing neurons. This system is located in the hypothalamic arcuate nucleus; it also includes the hypothalamic arcuate nucleus and the melanocortin 4 receptor (MC4R)-expressing neurons located in the hypothalamic paraventricular nucleus. The system regulates energy expenditure and food intake.

    • This question is part of the following fields:

      • Endocrinology
      • Medicine
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      Seconds

  • Question 45 - The formation of superoxide is catalysed by which enzyme? ...

    Incorrect

    • The formation of superoxide is catalysed by which enzyme?

      Your Answer:

      Correct Answer: NADPH oxidase

      Explanation:

      Superoxide is biologically toxic and is deployed by the immune system to kill invading microorganisms. In phagocytes, superoxide is produced in large quantities by the enzyme NADPH oxidase for use in oxygen-dependent killing mechanisms of invading pathogens.

    • This question is part of the following fields:

      • Cell Biology
      • Medicine
      0
      Seconds

  • Question 46 - What is the average life span of platelets? ...

    Incorrect

    • What is the average life span of platelets?

      Your Answer:

      Correct Answer: 8 days

      Explanation:

      The average life span of circulating platelets is 8 to 9 days.

    • This question is part of the following fields:

      • Haematology
      • Medicine
      0
      Seconds

  • Question 47 - What is the function of the acute phase protein, C-reactive protein? ...

    Incorrect

    • What is the function of the acute phase protein, C-reactive protein?

      Your Answer:

      Correct Answer: Opsonises bacteria

      Explanation:

      There are various immune reactions that become activated once the barrier between the body and environment has been compromised. There are certain opsonins that bind to the bacteria and facilitate phagocytosis. One of them is the acute phase protein: C protein. others include antibodies and complement.

    • This question is part of the following fields:

      • Immunology
      • Medicine
      0
      Seconds

  • Question 48 - Which of the following drugs would be the safest to prescribe in a...

    Incorrect

    • Which of the following drugs would be the safest to prescribe in a 22 year old man with seropositive rheumatoid arthritis who is planning to start a family?

      Your Answer:

      Correct Answer: Prednisolone

      Explanation:

      Prednisolone although has many undesirable side effects it may be considered relatively safe compared to the drugs that are provided here. Prolonged treatment with sulphasalazine may depress semen quality and cause irreversible infertility. Methotrexate and leflunomide both inhibit purine/pyrimidine synthesis (the former by inhibiting folate metabolism) and are contraindicated in pregnancy or while trying to conceive. In males, a temporary or permanent decrease in sperm count may occur with cyclophosphamide. Because the recovery of fertility after cyclophosphamide therapy is variable, sperm banking should be considered before treatment is begun.

    • This question is part of the following fields:

      • Connective Tissue
      • Medicine
      0
      Seconds

  • Question 49 - Which of the following drug can cause galactorrhoea? ...

    Incorrect

    • Which of the following drug can cause galactorrhoea?

      Your Answer:

      Correct Answer: Metoclopramide

      Explanation:

      Metoclopramide causes extrapyramidal effects (especially in children and young adults), hyperprolactinaemia, and occasionally tardive dyskinesia on prolonged administration. Also reported are drowsiness, restlessness, diarrhoea, depression, neuroleptic malignant syndrome, rashes, pruritus, oedema.

    • This question is part of the following fields:

      • Medicine
      • Pharmacology
      0
      Seconds

  • Question 50 - A study is carried out to assess the efficacy of a rapid urine...

    Incorrect

    • A study is carried out to assess the efficacy of a rapid urine screening test developed to detect Chlamydia. The total number of people involved in the study were 200. The study compared the new test to the already existing NAAT techniques. The new test was positive in 20 patients that were Chlamydia positive and in 3 patients that were Chlamydia negative. For 5 patients that were Chlamydia positive and 172 patients that were Chlamydia negative the test turned out to be negative. Choose the correct value regarding the negative predictive value of the new test:

      Your Answer:

      Correct Answer: 172/177

      Explanation:

      The definition of negative predictive value is the probability that the individuals with truly negative screening test don’t have Chlamydia. The equation is the following: Negative predictive value = Truly negative/(truly negative + false negative) = 172 / (172 + 5) = 172 / 177

    • This question is part of the following fields:

      • Medicine
      • Research Skills
      0
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Medicine (0/3) 0%
Pharmacology (0/1) 0%
Cardiovascular (0/2) 0%
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