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  • Question 1 - How does pregnancy affect the cardiac output of a patient? ...

    Correct

    • How does pregnancy affect the cardiac output of a patient?

      Your Answer: Increased cardiac output due to increase in heart rate and stroke volume

      Explanation:

      Cardiac Output increases to a similar degree as the blood volume. During the first trimester cardiac output is 30-40% higher than in the non-pregnant state. Steady rises are shown on Doppler echocardiography, from an average of 6.7 litres/minute at 8-11 weeks to about 8.7 litres/minute flow at 36-39 weeks; they are due, primarily, to an increase in stroke volume (35%) and, to a lesser extent, to a more rapid heart rate (15%). There is a steady reduction in systemic vascular resistance (SVR) which contributes towards the hyperdynamic circulation observed in pregnancy

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.7
      Seconds

  • Question 2 - According to Poiseuille’s formula, which 1 of the following will lead to increased...

    Incorrect

    • According to Poiseuille’s formula, which 1 of the following will lead to increased flow?

      Your Answer: Smaller pressure difference at 2 ends of tube

      Correct Answer: Shorter tube

      Explanation:

      V = π p r4 / 8 η lwhere V = discharge volume flow (m3/s)p = pressure difference between the ends of the pipe (N/m2, Pa)r = internal radius of pipe (m)l = length of pipe (m)η = viscosity of fluid

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.2
      Seconds

  • Question 3 - The basic unit of contraction in myocytes is: ...

    Correct

    • The basic unit of contraction in myocytes is:

      Your Answer: Sarcomere

      Explanation:

      Sarcomere is the organelle where calcium is stored to be released during contraction of the muscle. It is the basic unit of contraction in striated muscle fibers. As myocytes are also striated muscles, sarcomeres also forms the basic unit of contraction. The impulses travel along the membrane and via its interaction with the dihydropyridine receptors it releases the stored calcium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      1.9
      Seconds

  • Question 4 - The direct determinants of cardiac output are ...

    Correct

    • 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]

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.3
      Seconds

  • Question 5 - What is pulse pressure? ...

    Correct

    • What is pulse pressure?

      Your Answer: Difference between systolic and diastolic pressure

      Explanation:

      The pulse pressure is the difference between the measured systolic and diastolic pressures.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.9
      Seconds

  • Question 6 - 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
      2.7
      Seconds

  • Question 7 - Which of the following occurs during a Valsalva manoeuvre? ...

    Correct

    • Which of the following occurs during a Valsalva manoeuvre?

      Your Answer: An initial rise in blood pressure

      Explanation:

      The Valsalva maneuver involves forced expiration against a closed glottis. It has several phases, each affecting the cardiovascular system differently:

      1. Phase I: During the initial forced expiration against the closed glottis, there is a transient rise in intrathoracic pressure, which compresses the thoracic aorta and causes a brief increase in blood pressure.
      2. Phase II: Continued straining leads to decreased venous return to the heart, reducing cardiac output and causing a drop in blood pressure. This phase is characterized by a compensatory increase in heart rate.
      3. Phase III: Upon releasing the strain, there is a sudden drop in intrathoracic pressure, which momentarily decreases blood pressure.
      4. Phase IV: Blood pressure then rises rapidly as venous return to the heart is restored, leading to increased cardiac output. This is often followed by a reflex bradycardia (slow heart rate).

      Given these phases, the most accurate statement about what occurs during the Valsalva maneuver is the initial rise in blood pressure (Phase I).

      Other options explained:

      • Forced inspiration against a closed glottis: Incorrect. The Valsalva maneuver involves forced expiration, not inspiration, against a closed glottis.
      • Low intrathoracic pressures throughout: Incorrect. The Valsalva maneuver involves high intrathoracic pressures due to forced expiration.
      • Disruption of autonomic function: Incorrect. The Valsalva maneuver affects autonomic function but does not disrupt it. Instead, it triggers autonomic responses to changes in blood pressure and heart rate.
      • No change: Incorrect. The Valsalva maneuver causes significant changes in blood pressure and heart rate.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.5
      Seconds

  • Question 8 - Dicrotic notch is produced by which valves? ...

    Correct

    • Dicrotic notch is produced by which valves?

      Your Answer: Aortic

      Explanation:

      The graph of aortic pressure throughout the cardiac cycle displays a small dip (the incisure or dicrotic notch) which coincides with the aortic valve closure. The dip in the graph is immediately followed by a brief rise (the dicrotic wave) then gradual decline.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2
      Seconds

  • Question 9 - Coronary blood flow occurs in? ...

    Correct

    • Coronary blood flow occurs in?

      Your Answer: Diastole

      Explanation:

      Coronary arteries are unique in that they fill during diastole, when not occluded by valve cusps nor compressed by myocardial contraction).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      1.8
      Seconds

  • Question 10 - In the cardiac cycle, all of the following are true except: ...

    Incorrect

    • In the cardiac cycle, all of the following are true except:

      Your Answer: The left ventricular volume is maximal at the end of atrial systole

      Correct Answer: Mitral valve is closed by contraction of papillary muscles

      Explanation:

      Mitral valve is closed by contraction of papillary muscles: This statement is incorrect. The mitral valve closes due to the pressure difference between the left ventricle and the left atrium at the onset of ventricular systole. The papillary muscles contract to prevent prolapse of the valve into the atrium but do not cause the valve to close.

      The left ventricular volume is maximal at the end of atrial systole: This statement is true. At the end of atrial systole, the atria have pushed the remaining blood into the ventricles, making the ventricular volume maximal (end-diastolic volume).

      The left ventricular pressure is maximal just before the aortic valve opens: This statement is true. Left ventricular pressure peaks just before the aortic valve opens, as the ventricle contracts to overcome the pressure in the aorta.

      The ejection fraction is about 55%: This statement is true. The ejection fraction, which is the percentage of blood ejected from the ventricles with each contraction, is typically around 55%.

      The ‘a’ wave is due to atrial systole: This statement is true. The ‘a’ wave on the venous pressure curve corresponds to atrial systole, reflecting the increased pressure from atrial contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.6
      Seconds

  • Question 11 - Myocardium requires more oxygen to expel blood in: ...

    Correct

    • Myocardium requires more oxygen to expel blood in:

      Your Answer: A stenotic aortic valve

      Explanation:

      In aortic valve stenosis, increased ventricular pressure Is needed to expel the blood into the aorta. Increased pressure means increased contractility hence increase O2 consumption by the heart muscles.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      15.7
      Seconds

  • Question 12 - Calcium is mobilized from the sarcoplasmic reticulum through: ...

    Correct

    • Calcium is mobilized from the sarcoplasmic reticulum through:

      Your Answer: Ryanodine receptor (RyR2) calcium release channels

      Explanation:

      During the plateau phase of the action potential, calcium from the extracellular fluid enters through the L type of calcium channels. This entry triggers the release of more calcium from the sarcoplasmic reticulum via the ryanodine receptors. As a result intracellular calcium increases binding to troponin C resulting in contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.9
      Seconds

  • Question 13 - 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
      2.4
      Seconds

  • Question 14 - Catecholamines… ...

    Incorrect

    • Catecholamines…

      Your Answer: Decrease camp production

      Correct Answer: Activate adenylyl cyclase

      Explanation:

      Norepinephrine and epinephrine activate or deactivate adenylyl cyclase resulting in a decrease or an increase in the production of cAMP.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.5
      Seconds

  • Question 15 - In which organ will you find extremely porous sinusoidal capillaries, with discontinuous endothelium?...

    Correct

    • In which organ will you find extremely porous sinusoidal capillaries, with discontinuous endothelium?

      Your Answer: Liver

      Explanation:

      The liver is the organ which contains sinusoidal capillaries with discontinuous endothelium. The brain, lungs and the intestine all contain continuous capillaries, however the kidney contains fenestrated capillaries to aid in filtration.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.5
      Seconds

  • Question 16 - The AV Node: ...

    Correct

    • The AV Node:

      Your 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
      6.2
      Seconds

  • Question 17 - All valves are closed in which phase of the cardiac cycle? ...

    Incorrect

    • All valves are closed in which phase of the cardiac cycle?

      Your Answer: None of the above

      Correct Answer: Isovolumetric relaxation

      Explanation:

      The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.8
      Seconds

  • Question 18 - Myocardial contractility is improved by: ...

    Correct

    • Myocardial contractility is improved by:

      Your Answer: Caffeine

      Explanation:

      Caffeine and other theophyllines breakdown cAMP and have a positive ionotropic effect on the heart. Drugs like quinidine, procainamide and conditions like hypoxia and hypercapnia decreases the contractility of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.4
      Seconds

  • Question 19 - 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
      5.5
      Seconds

  • Question 20 - 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
      7.9
      Seconds

  • Question 21 - Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+...

    Correct

    • Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+ to troponin C results in all of the following except:

      Your Answer: Weakening of the troponin i interaction with actin

      Explanation:

      At rest, troponin i is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When Calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin i which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.9
      Seconds

  • Question 22 - In cardiac muscle, which of the following is directly responsible for the release...

    Correct

    • In cardiac muscle, which of the following is directly responsible for the release of Ca2+ stored in the sarcoplasmic reticulum (calcium-induced calcium release)?

      Your Answer: Ryanodine receptor (RyR)

      Explanation:

      Ryanodine receptor (RyR) is a ligand-gated Ca2+ channel with Ca2+ as its natural ligand. In skeletal muscle, Ca2+ entry from ECF by this route is not required for Ca2+ release. Instead, the DHPR that serves as the voltage sensor unlocks release of Ca2+ from the nearby SR via physical interaction with the RyR. The release is amplified through ca-induced ca release. However, in cardiac muscle, it is the influx of extracellular Ca2+ through the voltage-sensitive DHPR in the T system that triggers ca-induced ca release trough the RyR at the SR.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.5
      Seconds

  • Question 23 - Coronary arteries fill up during ...

    Correct

    • Coronary arteries fill up during

      Your Answer: Diastole

      Explanation:

      During contraction of the ventricular myocardium (systole), the subendocardial coronary vessels (the vessels that enter the myocardium) are compressed due to the high ventricular pressures. This compression results in momentary retrograde blood flow (i.e., blood flows backward toward the aorta) which further inhibits perfusion of myocardium during systole. However, the epicardial coronary vessels (the vessels that run along the outer surface of the heart) remain open. Because of this, blood flow in the sub endocardium stops during ventricular contraction. As a result, most myocardial perfusion occurs during heart relaxation (diastole) when the subendocardial coronary vessels are open and under lower pressure.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.5
      Seconds

  • Question 24 - Troponin I is inhibited by calcium binding to: ...

    Correct

    • Troponin I is inhibited by calcium binding to:

      Your Answer: Troponin c

      Explanation:

      At rest troponin I is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin I which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.6
      Seconds

  • Question 25 - Which one of the following is a cause of a soft second heart...

    Incorrect

    • Which one of the following is a cause of a soft second heart sound?

      Your Answer: Pulmonary hypertension

      Correct Answer: Aortic stenosis

      Explanation:

      Second heart sound (S2) forms the dub of lub-dub and is composed of components A2 and P2. •    loud: hypertension•    soft: AS•    fixed split: physiological split (normally occurs during inhalation), right bundle branch block, pulmonary stenosis, and atrial septal defect.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.5
      Seconds

  • Question 26 - Ventricular depolarization plus ventricular repolarization is shown by the _____ interval ...

    Correct

    • Ventricular depolarization plus ventricular repolarization is shown by the _____ interval

      Your Answer: QT

      Explanation:

      The QT interval represents ventricular depolarization as well as ventricular repolarization.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.1
      Seconds

  • Question 27 - Which factors increase the end-diastolic volume? ...

    Correct

    • Which factors increase the end-diastolic volume?

      Your Answer: Constriction of veins

      Explanation:

      End diastolic volume is also known as preload. It is the amount of blood the heart contracts against. Constriction of veins will decrease venous pooling and increase venous return, hence increasing the end diastolic volume. Standing will increase venous pooling hence decreasing venous return and end diastolic volume. Raised intrapericardial pressure will also decrease venous return and hence end diastolic volume.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.6
      Seconds

  • Question 28 - Which of the following factors serve to decrease cardiac output? ...

    Correct

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

      Your 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
      6.2
      Seconds

  • Question 29 - Currents caused by opening of which of the following channels contribute to the...

    Correct

    • Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?

      Your Answer: Potassium channels

      Explanation:

      Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.4
      Seconds

  • Question 30 - Which of the following supplies the AV node? ...

    Correct

    • Which of the following supplies the AV node?

      Your Answer: Right coronary artery

      Explanation:

      The AV node is supplied by the right coronary artery near the origin of the posterior IV artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.6
      Seconds

  • Question 31 - Why is the sub-endocardial portion of the left ventricle the most common site...

    Correct

    • Why is the sub-endocardial portion of the left ventricle the most common site for ischaemic damage and myocardial infarction?

      Your Answer: No blood flow occurs during systole

      Explanation:

      The subendocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.1
      Seconds

  • Question 32 - The interventricular septum is supplied anteriorly by the? ...

    Correct

    • The interventricular septum is supplied anteriorly by the?

      Your 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
      3.1
      Seconds

  • Question 33 - Which of the following best describes the cardiac muscle? ...

    Incorrect

    • Which of the following best describes the cardiac muscle?

      Your Answer: Smooth and involuntary

      Correct Answer: Striated and involuntary

      Explanation:

      Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.1
      Seconds

  • Question 34 - Which of the following phases in depolarization and repolarization of cardiac muscle cells...

    Incorrect

    • Which of the following phases in depolarization and repolarization of cardiac muscle cells are caused by the inactivation of Na+ channels?

      Your Answer: Phase 2 : plateau

      Correct Answer: Phase 1 : rapid repolarization

      Explanation:

      Phase 0 is caused by the sodium current. Voltage gated sodium channels open leading to the influx of sodium into the cardiac muscle cell. Phase 1 is the rapid transient repolarization phase which is caused by the inactivation of the voltage gated sodium channels and opening of the voltage gated potassium channels along with opening of the slow calcium channels. Phase 2 which is the plateau is caused by opening of the slow calcium channels. Phase 4 is caused by closing of the slow calcium channels and opening of the potassium channels leading to efflux of potassium leading to the establishment of the resting membrane potential.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.7
      Seconds

  • Question 35 - Which of the following statements is true regarding pulsus alternans? ...

    Correct

    • Which of the following statements is true regarding pulsus alternans?

      Your Answer: It is found in association with a third heart sound

      Explanation:

      Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis. A pathological third heart sound is usually associated.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.7
      Seconds

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

    Correct

    • B1 adrenergic stimulation produces:

      Your 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
      9.4
      Seconds

  • Question 37 - When observing a JVP, which of the following would lead to prominent v...

    Correct

    • When observing a JVP, which of the following would lead to prominent v waves?

      Your Answer: Tricuspid regurgitation

      Explanation:

      The v wave corresponds to Venous filling when the tricuspid valve is closed and venous pressure increases from venous return. In Tricuspid regurgitation there is additional blood from the regurgitant flow and thus this leads to a more prominent V wave.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.8
      Seconds

  • Question 38 - The right border of the heart corresponds to which line on the surface...

    Incorrect

    • The right border of the heart corresponds to which line on the surface of the chest?

      Your Answer: Line drawn from the 3rd left costal cartilage to the 6th left costal cartilage

      Correct Answer: Line drawn from the 3rd right costal cartilage to the 6th right costal cartilage

      Explanation:

      The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.8
      Seconds

  • Question 39 - Endothelial cells are attached to adjacent cells by adherent junctions via: ...

    Correct

    • Endothelial cells are attached to adjacent cells by adherent junctions via:

      Your Answer: Cadherins

      Explanation:

      Cadherins are calcium dependant molecules that mediate cell to cell adhesions in epithelial and endothelial cells among others.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9
      Seconds

  • Question 40 - The major factor in controlling coronary artery blood flow is considered to be?...

    Incorrect

    • The major factor in controlling coronary artery blood flow is considered to be?

      Your Answer: Shear pressure in coronary vessels

      Correct Answer: Metabolites of oxygen consumption

      Explanation:

      There is a strong relationship between myocardial blood flow and oxygen consumption. This indicates that products of metabolism may cause vasodilation of the coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6
      Seconds

  • Question 41 - 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
      7.4
      Seconds

  • Question 42 - 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
      10.2
      Seconds

  • Question 43 - Which of the following antiarrhythmic drugs may be used in the treatment of...

    Correct

    • Which of the following antiarrhythmic drugs may be used in the treatment of long QT syndrome?

      Your Answer: Atenolol

      Explanation:

      Beta-blockers are the mainstay of treatment in long QT syndrome. Implantable cardioverter-defibrillators are the most effective treatment in genotypes with a high risk of recurrence.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.7
      Seconds

  • Question 44 - 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
      3.8
      Seconds

  • Question 45 - Regarding cardiac contractility, catecholamines exert their inotropic effect via: ...

    Correct

    • Regarding cardiac contractility, catecholamines exert their inotropic effect via:

      Your Answer: Β1-adrenergic receptors and gs

      Explanation:

      Catecholamines exert their inotropic effect on the heart via the B1 adrenergic receptors and Gs, stimulating adenyl cyclase and increasing the production of cAMP.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.7
      Seconds

  • Question 46 - Where does the SA node develop? ...

    Correct

    • Where does the SA node develop?

      Your Answer: From structures on the right side of the embryo.

      Explanation:

      The SA node develops from the right side of the embryo and the AV node from the left. This is the reason why in adults the right vagus supplies the SA node and the left vagus supplies the AV node.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.6
      Seconds

  • Question 47 - Hyperkalaemia [K+ =7meq/l] can lead to the following ECG changes [Ca++ normal] ...

    Correct

    • Hyperkalaemia [K+ =7meq/l] can lead to the following ECG changes [Ca++ normal]

      Your Answer: Peaked T waves

      Explanation:

      Hyperkalaemia causes the formation of tall tented T waves due to altered repolarization.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.9
      Seconds

  • Question 48 - How many molecules of myosin attach to actin at any given time? ...

    Correct

    • How many molecules of myosin attach to actin at any given time?

      Your Answer: 1

      Explanation:

      1 molecule of myosin binds to actin at any give time.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.6
      Seconds

  • Question 49 - In which area is depolarization initiated? ...

    Correct

    • In which area is depolarization initiated?

      Your Answer: SA node

      Explanation:

      SA node is the pacemaker of the heart. It determines the rate of contractions. It is the place where depolarization is initiated. It exhibits phase 4 depolarization or automaticity. Electrical impulses then spread to the AV node, purkinje fibers, bundle of his and the ventricular muscles.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.9
      Seconds

  • Question 50 - The process by which depolarization of the muscle fiber initiates contraction is called?...

    Incorrect

    • The process by which depolarization of the muscle fiber initiates contraction is called?

      Your Answer: Excitation – contraction coupling

      Correct Answer: Action potential

      Explanation:

      This process is known as an action potential. Upon generation of an action potential when depolarization reaches threshold, it spreads throughout the muscle fiber, resulting in generation of an excitation-contraction coupling leading to contraction of the muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.6
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (40/50) 80%
Medicine (40/50) 80%
Passmed
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