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Question 1
Incorrect
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What is the function of the BK channel on the vascular smooth muscle membrane?
Your Answer: Promotes smooth muscle contraction opening the voltage gated Ca2+ channel
Correct Answer: Massive K+ efflux, increasing membrane potential, and shutting off the voltage gated Ca2+ channel
Explanation:BK channels, also known as large-conductance calcium-activated potassium channels, play a critical role in regulating vascular smooth muscle tone. When BK channels open, they allow a large efflux of potassium ions (K+) out of the cell. This efflux of K+ causes the membrane potential to become more negative (hyperpolarization), which in turn leads to the closure of voltage-gated calcium channels. The closure of these calcium channels reduces the influx of calcium ions (Ca2+) into the smooth muscle cells, resulting in decreased intracellular calcium levels and subsequent relaxation of the smooth muscle.
Thus, BK channels promote smooth muscle relaxation by hyperpolarizing the membrane and reducing the activity of voltage-gated Ca2+ channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 2
Incorrect
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A 64 year old female presents with sudden onset pain, swelling and stiffness in her right knee. Her medical history is significant for osteoarthritis affecting her hand joints and diet controlled diabetes mellitus. On examination, the right knee is swollen, erythematous and tender. Which of the following tests would be most useful in the diagnosis of this case?
Your Answer: X-ray of the knee
Correct Answer: Aspiration and examination of the synovial fluid
Explanation:Arthrocentesis should usually be done when there is a suspicion of pseudogout or septic arthritis as in this case which leads to an early diagnosis and prompt treatment. Polarized microscopy demonstrates weakly positively birefringent rhomboid crystals which are blue when parallel to light and yellow when perpendicular to light. Elevated serum uric acid levels that cause gout are usually found after large consumption of alcohol or meat, or post surgery. Autoimmune diseases like SLE, RA etc require an autoimmune screen.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 3
Incorrect
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In the event of an overdose, haemodialysis is ineffective as a treatment modality for which of the following drugs?
Your Answer: Barbiturates
Correct Answer: Tricyclics
Explanation:Tricyclic compounds can’t be cleared by haemodialysis.Drugs that can be cleared with haemodialysis include: (BLAST)- Barbiturate- Lithium- Alcohol (inc methanol, ethylene glycol)- Salicylates- Theophyllines (charcoal hemoperfusion is preferable)Drugs which cannot be cleared with haemodialysis include:- Tricyclics- Benzodiazepines- Dextropropoxyphene (Co-proxamol)- Digoxin- Beta-blockers
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 4
Correct
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Regarding cardiac output, an increased ejection fraction results from increases in which of the following?
Your Answer: Strength of contraction without increase in muscle fiber length
Explanation:When the strength of contraction increases without an increase in fiber length, the EF increases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Correct
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Which factor produced by the endothelium is responsible for the regulation of vascular cell growth?
Your Answer: Vascular endothelial growth factor (VEGF)
Explanation:VEGF is produced by the endothelial cells and is the major growth factor responsible for causing vasculogenesis. Some isoforms of this growth factor also have a prominent role in formation of lymphatic vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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The cells that secrete pepsinogen and gastric lipase are found in which part of the stomach?
Your Answer: Body and fundus
Explanation:Stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Cells that secret the inactive form of pepsin or pepsinogen are chief cells and are abundant in the body (corpus) and the fundus region of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 7
Incorrect
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A 30-year-old woman is admitted for drainage of an abscess in her left forearm. She has revealed that she was regular heroin user and has stopped for the past few days. Clinical signs are pointing towards opioid withdrawal. What is the next step in managing this patient?
Your Answer: Ask her how much heroin she uses per day and arrange for her to receive methadone syrup equivalent to this divided into four doses per day
Correct Answer: Give her 10 mg of methadone syrup and wait 60 min to determine its effect
Explanation:The next step in managing this patient is to give 10 mg and continue administering in 10 mg increments each hour until symptoms are under control.Methadone alleviates opioid withdrawal symptoms and reduces cravings. Methadone is useful for detoxification from longer-acting opioids such as morphine or methadone itself.Methadone should be used with caution if the patient has:Respiratory deficiencyAcute alcohol dependenceHead injuryTreatment with monoamine oxidase inhibitors (MAOIs)Ulcerating colitis or Crohn’s diseaseSevere hepatic impairmentThe dose must be reviewed on a daily basis and adjusted based upon how well the symptoms are controlled and the presence of side effects. The greater the dose of opioids used by the patient, the greater the dose of methadone required to control withdrawal symptoms. To avoid the risk of overdose in the first days of treatment The recommended dosing of methadone is 30mg in two doses of 15mg morning and evening.It is important to note that a methadone dose equivalent to what the patient reports they are taking should never be given. It is rare to need more than 40 mg per 24 hours: beware of overdosing which can lead to respiratory arrest.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 8
Incorrect
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In a 60kg adult male with normal mean arterial pressure and oxygen consumption, what proportion of the cardiac output at rest goes to the brain?
Your Answer: 15-20%
Correct Answer: 10-15%
Explanation:The rate of cerebral blood flow in the adult is typically 750 millilitres per minute, which is 10-15% of the cardiac output. On average around 13.9% of cardiac output is distributed to the brain.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 9
Correct
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The Cellular Theory of Ageing involves?
Your Answer: Loss of telomeres
Explanation:Cellular theories of aging propose that human aging is the result of cellular aging, whereby an increasing proportion of cells reach senescence, a terminal stage at which cells will cease to divide. This will limit the body’s ability to regenerate and to respond to injury or stress. Telomeres are bits of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause DNA to abnormally function. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence or cellular aging.
Other theories include:
- The Free Radical Theory: Implicates the gradual accumulation of oxidative cellular damage as a fundamental driver of cellular aging. This theory has evolved over time to emphasize the role of free radical induced mitochondrial DNA (mtDNA) mutations and the accumulation of mtDNA deletions. Given the proximity of mtDNA to the electron transport chain, a primary producer of free radicals, it postulates that the mutations would promote mitochondrial dysfunction and concomitantly increase free radical production in a positive feedback loop. It is known that diet, lifestyle, drugs (e.g. tobacco and alcohol) and radiation etc., are all accelerators of free radical production within the body.
- Error theory: based on the idea that errors can occur in the transcription of the synthesis of DNA. These errors are perpetuated and eventually lead to systems that do not function at the optimum level. The organism’s aging and death are attributable to these events (Sonneborn, 1979).
- The Cross-Linking Theory: also referred to as the Glycosylation Theory of Aging. In this theory it is the binding of glucose (simple sugars) to protein, (a process that occurs under the presence of oxygen) that causes various problems. Once this binding has occurred the protein becomes impaired and is unable to perform as efficiently. Living a longer life is going to lead to the increased possibility of oxygen meeting glucose and protein and known cross-linking disorders include senile cataract and the appearance of tough, leathery and yellow skin.
- The Neuroendocrine Theory First proposed by Professor Vladimir Dilman and Ward Dean MD, this theory elaborates on wear and tear by focusing on the neuroendocrine system. This system is a complicated network of biochemicals that govern the release of hormones which are altered by the walnut sized gland called the hypothalamus located in the brain. The hypothalamus controls various chain-reactions to instruct other organs and glands to release their hormones etc. The hypothalamus also responds to the body hormone levels as a guide to the overall hormonal activity. But as we grow older the hypothalamus loses it precision regulatory ability and the receptors which uptake individual hormones become less sensitive to them. Accordingly, as we age the secretion of many hormones declines and their effectiveness (compared unit to unit) is also reduced due to the receptors down-grading
- The Membrane Theory of Aging: According to this theory it is the age-related changes of the cell’s ability to transfer chemicals, heat and electrical processes that impair it. As we grow older the cell membrane becomes less lipid (less watery and more solid). This impedes its efficiency to conduct normal function and in particular there is a toxic accumulation
- The Decline Theory: The mitochondria are the power producing organelles found in every cell of every organ. Their primary job is to create Adenosine Triphosphate (ATP) and they do so in the various energy cycles that involve nutrients such as Acetyl-L-Carnitine, CoQ10 (Idebenone), NADH and some B vitamins etc. Enhancement and protection of the mitochondria is an essential part of preventing and slowing aging. Enhancement can be achieved with the above mention nutrients, as well as ATP supplements themselves.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 10
Correct
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Which of the following conditions is procoagulant?
Your Answer: Factor V Leiden
Explanation:Factor V Leiden is a genetic mutation of one of the clotting factors in the blood, Factor V. This mutation makes Factor V resistant to inactivation by activated Protein C, which normally helps to regulate clot formation. As a result, individuals with Factor V Leiden are at increased risk of developing abnormal blood clots (thrombophilia), making it a procoagulant condition.
The other conditions listed are associated with bleeding tendencies rather than increased clotting:
- Afibrinogenemia: A rare genetic disorder where there is a complete lack of fibrinogen, leading to bleeding problems.
- Hemophilia: A group of inherited bleeding disorders where blood does not clot properly due to the lack of sufficient blood-clotting proteins (factors VIII or IX).
- Hypothrombinemia: A condition characterized by low levels of prothrombin, leading to increased bleeding.
- Christmas disease (Hemophilia B): A form of hemophilia caused by a deficiency of factor IX, resulting in a bleeding tendency.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 11
Correct
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The direct determinants of cardiac output are
Your Answer: Stroke volume and heart rate
Explanation:Cardiac output is classically defined alongside stroke volume (SV) and the heart rate (HR) as:Cardiac Output [L/min] = Stroke Volume [L/beat] x Heart Rate [beats/min]
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Correct
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Nucleic acids are split into nucleotides in the:
Your Answer: Intestine
Explanation:The pancreas is the major source for all the digestive enzymes including nucleases which split nucleic acids into nucleotides primarily in the small intestine.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 13
Correct
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A 39 year old woman with a history of rheumatoid arthritis has recently been switched from methotrexate to leflunomide. Monitoring of full blood count and LFTs has been carried out. Which of the following parameters should also be monitored in this case?
Your Answer: Blood pressure
Explanation:Blood pressure should be routinely measured as leflunomide may cause hypertension and thus an increase in BP. It doesn’t cause changes in blood sugar levels, peak expiratory flow rate or haematuria.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 14
Incorrect
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The layers of the neocortex from the 1st to the 6th are arranged as follows:
Your Answer: Internal granular, internal pyramidal, multiform, molecular, external granular, external pyramidal
Correct Answer: Molecular, external granular, external pyramidal, internal granular, internal pyramidal, multiform
Explanation:The layers of neocortex from outermost to innermost include: the molecular, external granular layer, external pyramidal, internal granular, internal pyramidal and multiform layer.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 15
Incorrect
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Which of the following is a precursor to the tissue macrophage?
Your Answer: Normoblast
Correct Answer: Monocyte
Explanation:Monocytes are a type of white blood cell, or leukocyte. They are the largest type of leukocyte and can differentiate into macrophages or dendritic cells.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 16
Incorrect
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Empagliflozin was found to reduce the risk of cardiovascular deaths, non-fatal myocardial infarction and non-fatal stroke when added to standard treatment plans in patients with type 2 diabetes mellitus. This information was shared in 2015 by The New England Journal of Medicine and the results were expressed per 1000 patient years. In fact, empagliflozin had an event rate of 37.3/1000 patient years and placebo an event rate of 43.9/1000 patient years. How many patients who are at high cardiovascular risk need to be treated with empagliflozin to prevent a cardiovascular death, a non-fatal myocardial infarction or a non-fatal stroke?
Your Answer: 100
Correct Answer: 150
Explanation:The number needed to treat (NNT) is an absolute effect measure that has been used to assess beneficial and harmful effects of medical interventions. In this case the NNT can be calculated as follows: NNT = 1/ Absolute risk reduction (ARR). ARR=(Control event rate expressed per 1000 patient years) – (Experimental event rate expressed per 1000 patient years) = 43.9-37.3 = 6.6/1000 patient yearsNNT=(Patient years)/ARR = 1000/ 6.6 = 151.5. The closest to 151.5 is 150, thus it is the correct answer.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 17
Incorrect
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The length of DNA is generally measured in terms of number of:
Your Answer: Histones
Correct Answer: Base pairs
Explanation:As DNA is made up of nucleotides, its length is measured by the number of base pairs in the DNA molecules.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 18
Incorrect
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With regards to environmental temperature, for each degree Celsius of elevation, the metabolic rate rises?
Your Answer: 0.12
Correct Answer: 0.14
Explanation:An increase in body temperature is associated with a higher metabolic rate. Evidence suggests that an increase of 1°C in your body temperature increases your metabolism by 10 to 14%.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 19
Incorrect
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Which of the following options best describes rheumatoid factor?
Your Answer: IgM against the Fc portion of IgA
Correct Answer: IgM against the Fc portion of IgG
Explanation:Rheumatoid factor is an IgM antibody that targets the Fc portion of IgG.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 20
Incorrect
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Antibiotic resistance may happen by:
Your Answer:
Correct Answer: By enzymes which inactivate the drug
Explanation:The three main mechanisms of antibiotic resistance are, enzymatic degradation of antibacterial drugs, alteration of bacterial proteins that are antimicrobial targets, and changes in membrane permeability to antibiotics.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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