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  • Question 1 - The AV Node: ...

    Incorrect

    • The AV Node:

      Your Answer: It is a complex spindle shaped structure located in the interventricular septum

      Correct Answer: It decelerates impulses passing to the ventricles

      Explanation:

      The action potentials in the sinoatrial (SA) and atrioventricular (AV) nodes are largely due to Ca2+, with no contribution by Na+ influx. The depolarization continues to conduct slowly through the atrioventricular (AV) node. The AV node is located in the right posterior portion of the interatrial septum. This is small and bean-shaped. The atrial conductive system is organized so that the cardiac impulse does not travel from the atria into the ventricles too rapidly; this delay allows the atria to empty before ventricular contraction begins. It is the AV node and its adjacent conductive fibers that delay this transmission into the ventricles. Conduction through the AV Node is represented on the ECG by the PR interval.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16
      Seconds

  • Question 2 - Where would one normally find venous valves? ...

    Correct

    • Where would one normally find venous valves?

      Your Answer: Saphenous vein

      Explanation:

      The intima of the limb veins is folded at intervals to form venous valves that prevent retrograde flow. There are no valves present in the very small veins, the great veins, or the veins in the brain and viscera.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.1
      Seconds

  • Question 3 - During exercise, a man consumes 2L O2/min, his arterial 02 content is 190...

    Correct

    • During exercise, a man consumes 2L O2/min, his arterial 02 content is 190 ml/l and the 02 content of his mixed venous blood is 130ml/l. His cardiac output is approximately:

      Your Answer: 33l/min

      Explanation:

      In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Therefore CO = 2/(0.190-0.130) = 33l/minNote that (Ca – Cv) is also known as the arteriovenous oxygen difference.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.4
      Seconds

  • Question 4 - The interventricular septum is supplied anteriorly by the? ...

    Incorrect

    • The interventricular septum is supplied anteriorly by the?

      Your Answer: Marginal branch of the right coronary artery

      Correct Answer: Left anterior descending artery

      Explanation:

      The anterior interventricular artery or left anterior descending artery supplies the anterior 2/3rds of the interventricular septum.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.3
      Seconds

  • Question 5 - 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
      5.9
      Seconds

  • Question 6 - 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
      8.7
      Seconds

  • Question 7 - What is the effect of catecholamines (i.e. increased heart rate) on the pressure...

    Incorrect

    • What is the effect of catecholamines (i.e. increased heart rate) on the pressure volume loop?

      Your Answer: Shifts the diastolic pressure curve to the right

      Correct Answer: Shifts the diastolic pressure curve upward and leftward

      Explanation:

      Catecholamines have a positive ionotropic and chronotropic effect on the heart. The ventricles develop greater tension during systole resulting in an increase in the stroke volume. The increase in stroke volume results in a decrease in the end diastolic volume. This pushes the loop towards the left and upwards.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.3
      Seconds

  • Question 8 - Regarding the length of systole and diastole which of the following is true?...

    Correct

    • Regarding the length of systole and diastole which of the following is true?

      Your Answer: The duration of systole is more fixed than diastole

      Explanation:

      The duration of systole is more fixed than the duration of diastole. When the heart rate increases the timing of systole remains more or less the same however, diastole decreases.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      26.4
      Seconds

  • Question 9 - All of the following are consistent with the indicator dilution method except--- ...

    Incorrect

    • All of the following are consistent with the indicator dilution method except---

      Your Answer: The cardiac output is equal to the amount of indicator injected divided by its average concentration in arterial blood after a single circulation though the heart

      Correct Answer: In thermodilution, the indicator used is warm saline

      Explanation:

      In thermodilution, the indicator used is cold saline.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      19.5
      Seconds

  • Question 10 - In a normal heart rate at rest, the left ventricular end-diastolic volume is...

    Correct

    • In a normal heart rate at rest, the left ventricular end-diastolic volume is ….

      Your Answer: 100-130 ml

      Explanation:

      In cardiovascular physiology, end-diastolic volume (EDV) is the volume of blood in the right and/or left ventricle at end load or filling in (diastole) or the amount of blood in the ventricles just before systole. Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in cardiac muscle prior to contraction (systole). End-diastolic volume: Right = 144 mL(± 23mL) & Left = 142 mL (± 21 mL).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.2
      Seconds

  • Question 11 - Regarding the cardiac muscle striations as viewed under the microscope, which areas are...

    Correct

    • Regarding the cardiac muscle striations as viewed under the microscope, which areas are dark?

      Your Answer: A band and z line

      Explanation:

      Dark bands: a, h. Dark line: z. Clear band: i, m

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.6
      Seconds

  • Question 12 - Sinus bradycardia may be caused by disease of which of the following: ...

    Correct

    • Sinus bradycardia may be caused by disease of which of the following:

      Your Answer: Right coronary artery

      Explanation:

      Disease of the right coronary artery may cause sinus bradycardia and AV nodal block.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.4
      Seconds

  • Question 13 - Endothelial cells produce the following substance(s): ...

    Correct

    • Endothelial cells produce the following substance(s):

      Your Answer: All of the above

      Explanation:

      Endothelial cells produce thromboxane, prostacyclins, nitric oxides, endothelins, IL-1 and TNF.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.9
      Seconds

  • Question 14 - B1 adrenergic stimulation produces: ...

    Incorrect

    • B1 adrenergic stimulation produces:

      Your Answer: Decrease in cAMP

      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
      6.1
      Seconds

  • Question 15 - The coronary sinus, which empties into the right atrium, serves to? ...

    Incorrect

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

      Your Answer: Supply the right atrium

      Correct 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
      13.5
      Seconds

  • Question 16 - The V wave in the jugular pulse is caused by: ...

    Incorrect

    • The V wave in the jugular pulse is caused by:

      Your Answer: Ventricular filling

      Correct Answer: Atrial filling

      Explanation:

      The v wave reflects the passive increase in pressure and volume of the right atrium as it fills in late systole and early diastole.

      The jugular vein pulsations usually have two elevations and two troughs. The first elevation (a wave) corresponds to the slight rise in atrial pressure resulting from atrial contraction. The first descent (x descent) reflects a fall in atrial pressure that starts with atrial relaxation. The second elevation (v wave) corresponds to ventricular systole when blood is entering the right atrium from the vena cavae while the tricuspid valve is closed. Finally, the second descent (y descent) reflects falling right atrial pressure as the tricuspid valve opens and blood drains from the atrium into the ventricle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.7
      Seconds

  • Question 17 - Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:...

    Incorrect

    • Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:

      Your Answer: Voltage-gated Ca2+ channels

      Correct Answer: Serca (sarcoplasmic or endoplasmic reticulum Ca2+ ATPase)

      Explanation:

      Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      1.1
      Seconds

  • Question 18 - Which of the following suggests the presence of mitral regurgitation as well as...

    Incorrect

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

      Your Answer: Localised tapping apex beat

      Correct 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
      7.7
      Seconds

  • Question 19 - Stroke volume in a average sized man lying in supine position is about?...

    Correct

    • Stroke volume in a average sized man lying in supine position is about?

      Your Answer: 70 ml

      Explanation:

      The stroke volume of an average sized man who is lying is the supine position is about 70 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.2
      Seconds

  • Question 20 - What is the most common cardiac defect seen in patients with Down’s syndrome?...

    Correct

    • What is the most common cardiac defect seen in patients with Down’s syndrome?

      Your Answer: Atrioventricular septal defect

      Explanation:

      The rate of congenital heart disease in new-borns with Down syndrome is around 40%. Of those with heart disease, about 80% have an atrioventricular septal defect or ventricular septal defect with the former being more common. Mitral valve problems become common as people age, even in those without heart problems at birth.[3] Other problems that may occur include tetralogy of Fallot and patent ductus arteriosus.[38] People with Down syndrome have a lower risk of hardening of the arteries

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.2
      Seconds

  • Question 21 - Which is the most common site for primary cardiac tumours to occur in...

    Correct

    • Which is the most common site for primary cardiac tumours to occur in adults?

      Your Answer: Left atrium

      Explanation:

      Myxomas are the most common type of primary heart tumour. The tumour is derived from multipotential mesenchymal cells and may cause a ball valve-type obstruction. About 75% of myxomas occur in the left atrium of the heart, usually beginning in the wall that divides the two upper chambers of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.1
      Seconds

  • Question 22 - The branche(s) of the left coronary artery include: ...

    Correct

    • The branche(s) of the left coronary artery include:

      Your Answer: Left circumflex artery & anterior interventricular artery

      Explanation:

      The left main coronary divides into branches:

      1. The left anterior descending artery branches off the left coronary artery and supplies blood to the front of the left side of the heart.

      2. The circumflex artery branches off the left coronary artery and encircles the heart muscle.

      The anterior interventricular artery is otherwise known as the anterior descending branch. The posterior descending artery comes from Right coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.4
      Seconds

  • Question 23 - The Plateau phase in myocyte action potentials does all of the following except:...

    Incorrect

    • The Plateau phase in myocyte action potentials does all of the following except:

      Your Answer: This phase is unique to myocytes

      Correct Answer: It allows early reactivation of the myocytes

      Explanation:

      The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. 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 (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.1
      Seconds

  • Question 24 - Which of the following is a method for measurement of cardiac output? ...

    Incorrect

    • Which of the following is a method for measurement of cardiac output?

      Your Answer: Starling method

      Correct Answer: Indicator dilution method

      Explanation:

      There are two methods of calculating the cardiac output in humans other than doppler with echocardiography: The direct Fick’s method and the indicator dilution method. In the indicator dilution technique, a known amount of a substance such as a dye or, more commonly, a radioactive isotope is injected into an arm vein and the concentration of the indicator in serial samples of arterial blood is determined. The output of the heart is equal to the amount of indicator injected divided by its average concentration in arterial blood after a single circulation through the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.6
      Seconds

  • Question 25 - The isoforms of nitric oxide synthase which are found in the nervous system...

    Incorrect

    • The isoforms of nitric oxide synthase which are found in the nervous system (NOS1) and endothelial cells (NOS3) are activated by agents that increase which of the following intracellular electrolytes?

      Your Answer: Na

      Correct Answer: Ca

      Explanation:

      Synthesis of nitric oxide is stimulated by activation of the NMDA receptors by certain agents. This leads to opening of the Calcium channels and an influx of calcium into the cell. This will activate the nitric oxide synthase. Nitric oxide is produced on demand.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.7
      Seconds

  • Question 26 - Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?...

    Incorrect

    • Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?

      Your Answer: Ryanodine receptors

      Correct Answer: Dihydropyridine receptors

      Explanation:

      Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ form the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors.

      Dihydropyridine receptors (DHPRs), are voltage-gated Ca2+ channels, and ryanodine receptors (RyRs), which are intracellular Ca2+ release channels, are expressed in diverse cell types, including skeletal and cardiac muscle.

      Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.3
      Seconds

  • Question 27 - Which of the following factors serve to decrease cardiac output? ...

    Incorrect

    • Which of the following factors serve to decrease cardiac output?

      Your Answer: Pregnancy

      Correct Answer: Standing from a lying position

      Explanation:

      Sleep has no effect on the cardiac output. Anxiety, excitement, increased body temperature and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0.8
      Seconds

  • Question 28 - In the Fick‘s method of measuring cardiac output, the arterial oxygen content can...

    Correct

    • In the Fick‘s method of measuring cardiac output, the arterial oxygen content can be measured in a sample obtained from

      Your Answer: The pulmonary vein

      Explanation:

      In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Note that (Ca – Cv) is also known as the arteriovenous oxygen difference.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.4
      Seconds

  • Question 29 - Closure of the tricuspid valve is marked by which of the following features...

    Incorrect

    • Closure of the tricuspid valve is marked by which of the following features of the jugular venous waveform?

      Your Answer: a wave

      Correct Answer: c wave

      Explanation:

      The jugular venous pressure (JVP) classically has three upward deflections and two downward deflections. The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling. The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.9
      Seconds

  • Question 30 - Describe the location of the SA node: ...

    Incorrect

    • Describe the location of the SA node:

      Your Answer: Posterior portion of the right interatrial septum

      Correct Answer: Junction of the SVC and right atrium

      Explanation:

      Anatomically the SA node is located at the junction of the superior vena cava and the right atrium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0.9
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (14/30) 47%
Medicine (14/30) 47%
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