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  • Question 1 - Which of the following are responsible for the 4th heart sound? ...

    Correct

    • Which of the following are responsible for the 4th heart sound?

      Your Answer: Ventricular hypertrophy

      Explanation:

      The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle in atrial systole.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.8
      Seconds

  • Question 2 - The coronary sinus, which empties into the right atrium, serves to? ...

    Correct

    • The coronary sinus, which empties into the right atrium, serves to?

      Your Answer: Drain the venous supply of the myocardium

      Explanation:

      The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena cava.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.9
      Seconds

  • Question 3 - Regarding cardiac output, an increased ejection fraction results from increases in which of...

    Incorrect

    • Regarding cardiac output, an increased ejection fraction results from increases in which of the following?

      Your Answer: Strength of contraction with increase in muscle fiber length

      Correct 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      24.7
      Seconds

  • Question 4 - The end- diastolic ventricular volume is about? ...

    Correct

    • The end- diastolic ventricular volume is about?

      Your Answer: 130 ml

      Explanation:

      The end diastolic volume in a healthy individual is about 130 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      1.9
      Seconds

  • Question 5 - What is the isolated effect of B2 stimulation on the coronaries? ...

    Correct

    • What is the isolated effect of B2 stimulation on the coronaries?

      Your Answer: Vasodilatation

      Explanation:

      Norepinephrine and epinephrine are agonists for all adrenergic receptor subtypes, although with varying affinities. Based on their physiology and pharmacology, adrenergic receptors have been divided into two principal types: alpha and beta. These types have been further differentiated into alpha-1, alpha-2, b1, and b2 receptors.

      Alpha-1 Receptors are located on postsynaptic cells in smooth muscle and elicit vasoconstriction.

      Alpha-2 receptors are localized on presynaptic membranes of postganglionic nerve terminals that synthesize norepinephrine. When activated by catecholamines, alpha-2 receptors act as negative feedback controllers, inhibiting further norepinephrine release.

      Activation of myocardial b1 receptors stimulates the rate and strength of cardiac contraction, and consequently increases cardiac output. b1 Receptor activation also stimulates renin release from the kidney. Another class of antihypertensive agents acts by inhibiting b1 receptors.

      Activation of b2 receptors by epinephrine relaxes vascular smooth muscle and results in vasodilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.7
      Seconds

  • Question 6 - Activation of nitric oxide synthesis by endothelial cells is triggered by: ...

    Correct

    • Activation of nitric oxide synthesis by endothelial cells is triggered by:

      Your Answer: All of the above

      Explanation:

      Acetylcholine, histamine, bradykinin, vasoactive intestinal peptide (VIP) and shear stress on the endothelial cells causing the release of NO. NO is formed from arginine and causes vasodilatation of the blood vessels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.5
      Seconds

  • Question 7 - Absolute refractory period in a cardiac action potential graph occurs during. ...

    Correct

    • Absolute refractory period in a cardiac action potential graph occurs during.

      Your Answer: All of the above

      Explanation:

      Absolute refractory period (ARP): the cell is completely unexcitable to a new stimulus and occurs from phase 0 – 2 i.e. depolarisation, early repolarisation and plateau phase.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6
      Seconds

  • Question 8 - Angina pectoris develops when blood through the coronary artery becomes: ...

    Correct

    • Angina pectoris develops when blood through the coronary artery becomes:

      Your Answer: Restricted, limiting blood blow

      Explanation:

      Angina pectoris develops when stenosis ( >70%) of the artery occurs as a result of formation of an atherosclerotic plaque. This leads to a decrease in the O2 carried to the thickened heart muscle by the blood, leading to the characteristic chest pain associated with angina pectoris.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.3
      Seconds

  • Question 9 - What is the function of the BK channel on the vascular smooth muscle...

    Incorrect

    • What is the function of the BK channel on the vascular smooth muscle membrane?

      Your Answer: Massive K+ efflux, increasing membrane potential, and shutting off the voltage gated Ca2+ channel

      Correct Answer: Massive K+ influx, increasing membrane potential, and shutting off the voltage gated Ca2+ channel

      Explanation:

      In vascular smooth muscles, Ca2+ influx via the voltage gated calcium channels increases the cytosolic calcium, as well as causing the release of calcium from the sarcoplasmic reticulum. The high calcium concentration increases the activity of the calcium activated potassium channels. These are known as BK channels. Massive influx of potassium shuts off the voltage gated calcium channels and causes relaxation of the vascular smooth muscle.

      The large-conductance voltage and calcium-sensitive BK channel is important in many electrically active cells. Its unique sensitivity to both intracellular calcium levels and membrane potential makes it a key regulator of intracellular calcium, a critical second messenger in cells.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.6
      Seconds

  • Question 10 - Which of the following causes the closure of the ductus arteriosus during birth?...

    Correct

    • Which of the following causes the closure of the ductus arteriosus during birth?

      Your Answer: Reduced levels of prostaglandins

      Explanation:

      Ductus arteriosus is kept open by the prostaglandin E2 which is a vasodilator. At birth the high levels of cyclooxygenase blocks the production of prostaglandins which results in the closure of the ductus arteriosus.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.4
      Seconds

  • Question 11 - Vasodilatation of coronary arteries is caused by: ...

    Correct

    • Vasodilatation of coronary arteries is caused by:

      Your Answer: Hypoxia

      Explanation:

      The heart is highly metabolically active and boasts the highest oxygen consumption by mass of any organ. This demand for oxygen is met by the coronary circulation, which is responsible for delivering blood to the myocardium and represents approximately 5% of cardiac output. Vasodilation may be due to the local effect of hypoxia on coronary vessels, or local metabolic vasodilation, or the activation of β-adrenoceptors or some combination of these mechanisms.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      11.6
      Seconds

  • Question 12 - Isovolumetric ventricular contraction lasts for? ...

    Correct

    • Isovolumetric ventricular contraction lasts for?

      Your Answer: 0,05 s

      Explanation:

      Isovolumetric contraction lasts for about 0.05 seconds.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.1
      Seconds

  • Question 13 - The following products of the vascular endothelium produce vasodilation except: ...

    Correct

    • The following products of the vascular endothelium produce vasodilation except:

      Your Answer: Endothelin

      Explanation:

      Vascular endothelial growth factor (VEGF) is a signal protein produced by cells that stimulates vasculogenesis and angiogenesis. It is part of the system that restores the oxygen supply to tissues when blood circulation is inadequate. VEGF’s normal function is to create new blood vessels during embryonic development, new blood vessels after injury, muscle following exercise, and new vessels (collateral circulation) to bypass blocked vessels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.8
      Seconds

  • Question 14 - Which of the following suggests the presence of mitral regurgitation as well as...

    Correct

    • Which of the following suggests the presence of mitral regurgitation as well as mitral stenosis?

      Your Answer: Displaced apex beat

      Explanation:

      Mitral stenosis on its own does not lead to left ventricular dilatation and hence a displaced apex beat. Thus a displaced apex beat is suggestive of mixed mitral disease. The other options occur in mitral stenosis.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.7
      Seconds

  • Question 15 - Which vaso metabolite decreases coronary blood flow? ...

    Correct

    • Which vaso metabolite decreases coronary blood flow?

      Your Answer: Endothelin

      Explanation:

      Decreased O2, increased CO2, lactate, prostaglandins, adenine nucleotides, adenosine, H+, K+ and cyanide produce vasodilation and thus an increase in coronary blood flow.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.4
      Seconds

  • Question 16 - Concerning coronary arteries, what is the net effect of B2 stimulation on the...

    Incorrect

    • Concerning coronary arteries, what is the net effect of B2 stimulation on the heart (e.g. Running athlete)?

      Your Answer: Vasodilation directly

      Correct Answer: Vasodilation via production of metabolites

      Explanation:

      The coronary arterioles contain α-adrenergic receptors, which cause vasoconstriction, and β-adrenergic receptors, which cause vasodilation. Activity in the noradrenergic nerves to the heart and injections of norepinephrine cause coronary vasodilation. However, norepinephrine also increases the heart rate and the force of cardiac contraction, and the vasodilation is due to production of vasodilator metabolites in the myocardium secondary to the increase in its activity. As exercise has the same effect as sympathetic stimulation, it will result in vasodilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.5
      Seconds

  • Question 17 - Regarding cardiac muscle contractility, the afterload refers to: ...

    Correct

    • Regarding cardiac muscle contractility, the afterload refers to:

      Your 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
      5.8
      Seconds

  • Question 18 - Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by...

    Correct

    • Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by binding of which molecule to the exposed site on the myosin.

      Your Answer: ATP

      Explanation:

      A crossbridge is a myosin projection, consisting of two myosin heads, that extends from the thick filaments. Each myosin head has two binding sites: one for ATP and another for actin. The binding of ATP to a myosin head detaches myosin from actin, thereby allowing myosin to bind to another actin molecule. Once attached, the ATP is hydrolysed by myosin, which uses the released energy to move into the cocked position whereby it binds weakly to a part of the actin binding site.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.3
      Seconds

  • Question 19 - What is the main reason for checking the urea and electrolytes prior to...

    Correct

    • What is the main reason for checking the urea and electrolytes prior to commencing a patient on amiodarone?

      Your Answer: To detect hypokalaemia

      Explanation:

      All antiarrhythmic drugs have the potential to cause arrhythmias. Coexistent hypokalaemia significantly increases this risk.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.6
      Seconds

  • Question 20 - The positive inotropic effect of digoxin is due to? ...

    Incorrect

    • The positive inotropic effect of digoxin is due to?

      Your Answer: Stimulation of calcium channels

      Correct Answer: Inhibition of the sodium potassium ATPase in the myocardium

      Explanation:

      Digitalis compounds are potent inhibitors of cellular Na+/K+-ATPase. This ion transport system moves sodium ions out of the cell and brings potassium ions into the cell. By inhibiting the Na+/K+-ATPase, cardiac glycosides cause the intracellular sodium concentration to increase. This then leads to an accumulation of intracellular calcium via the Na+/Ca++ exchange system. In the heart, increased intracellular calcium causes more calcium to be released by the sarcoplasmic reticulum, thereby making more calcium available to bind to troponin-C, which increases contractility (inotropy).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.1
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (16/20) 80%
Medicine (16/20) 80%
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