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  • Question 1 - 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
      5.9
      Seconds

  • Question 2 - 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
      3.9
      Seconds

  • Question 3 - Activation of baroreceptor reflex involves: ...

    Incorrect

    • Activation of baroreceptor reflex involves:

      Your Answer: Excitation of neurons in the rostral ventrolateral medulla (RVLM)

      Correct Answer: Short term regulation of systemic blood pressure

      Explanation:

      Baroreceptors are found in the heart and the blood vessels. They are the carotid sinus and the aortic arch receptors and respond to the minute to minute change in the blood pressure i.e. a change in the pulsatile pressure and not to a change in the mean arterial pressure. If the pulse pressure decreases, the rate of firing of the receptors decreases, stimulating an increase in the heart rate and blood pressure. Mechanisms that regulate the long term blood pressure control include the renin-angiotensin-aldosterone mechanism.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.6
      Seconds

  • Question 4 - The following determines the strength of contraction ...

    Correct

    • The following determines the strength of contraction

      Your Answer: Plateau phase

      Explanation:

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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5
      Seconds

  • Question 5 - 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
      13.6
      Seconds

  • Question 6 - The process by which depolarization of the muscle fiber initiates contraction is called?...

    Correct

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

      Your 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
      16.4
      Seconds

  • Question 7 - Concerning surface anatomy, where is the apex beat found? ...

    Correct

    • Concerning surface anatomy, where is the apex beat found?

      Your Answer: 5th intercostal space mid clavicular line

      Explanation:

      The location of the apex beat may vary but it is mostly found in the left 5th intercostal space 6 cm from the anterior median line or in the mid clavicular line.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.7
      Seconds

  • Question 8 - Myocardial fibers have a resting membrane potential of approximately: ...

    Correct

    • Myocardial fibers have a resting membrane potential of approximately:

      Your Answer: -90mv

      Explanation:

      The resting membrane potential of the mammalian heart is about -90 mv.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.2
      Seconds

  • Question 9 - Catecholamines… ...

    Correct

    • Catecholamines…

      Your 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
      2
      Seconds

  • Question 10 - What is cardiac output? ...

    Correct

    • What is cardiac output?

      Your Answer: Product of stroke volume and heart rate

      Explanation:

      Cardiac output is the product of stroke volume and heart rate.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.3
      Seconds

  • Question 11 - Which ion channel does not contribute to the myocardial action potential? ...

    Correct

    • Which ion channel does not contribute to the myocardial action potential?

      Your Answer: Chloride channel

      Explanation:

      The upstroke in the cardiac action potential is due to opening of the sodium channels and an influx of sodium into the cell. The initial repolarization phase is due to transient opening of the potassium channels along with calcium channels. Influx of calcium causes the prolonged plateau phase of the action potential. Delayed opening of the rectifier potassium channel and delayed closure of the calcium channel leads to the repolarization phase of cardiac action potential.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.1
      Seconds

  • Question 12 - Which vaso metabolite decreases coronary blood flow? ...

    Incorrect

    • Which vaso metabolite decreases coronary blood flow?

      Your Answer: Lactate

      Correct 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
      13.8
      Seconds

  • Question 13 - The heart rate can be accelerated by: ...

    Correct

    • The heart rate can be accelerated by:

      Your Answer: Exercise and thyroid hormones

      Explanation:

      The firing of the SA node will increase due to exercises and as the thyroid hormone has a chronotropic effect on the heart, it too will result in an increase in the heart rate via stimulation of the adrenergic receptors of the heart. As during exercise the sympathetic nervous system is activated, it will directly have an positive chronotropic effect on the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.3
      Seconds

  • Question 14 - Concerning S3, which of the following statements is INCORRECT? ...

    Correct

    • Concerning S3, which of the following statements is INCORRECT?

      Your Answer: Coincide with atrial contraction

      Explanation:

      A third heart sound also called a ventricular gallop occurs at the beginning of diastole after S2 and is lower in pitch than S1 or S2 as it is not of valvular origin. The third heart sound is benign in youth, some trained athletes, and sometimes in pregnancy but if it re-emerges later in life it may signal cardiac problems, such as a failing left ventricle as in dilated congestive heart failure (CHF). S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. It may also be a result of tensing of the chordae tendineae during rapid filling and expansion of the ventricle. In other words, an S3 heart sound indicates increased volume of blood within the ventricle. An S3 heart sound is best heard with the bell-side of the stethoscope (used for lower frequency sounds). A left-sided S3 is best heard in the left lateral decubitus position and at the apex of the heart, which is normally located in the 5th left intercostal space at the midclavicular line. A right-sided S3 is best heard at the lower-left sternal border. The way to distinguish between a left and right-sided S3 is to observe whether it increases in intensity with inhalation or exhalation. A right-sided S3 will increase on inhalation, while a left-sided S3 will increase on exhalation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8
      Seconds

  • Question 15 - The most resistant area in the brain to hypoxia is: ...

    Correct

    • The most resistant area in the brain to hypoxia is:

      Your Answer: Brain stem

      Explanation:

      The structures in the brainstem are more resistant to hypoxia than the cerebral cortex and the rest of the brain structures.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.5
      Seconds

  • Question 16 - The average end diastolic volume in a healthy individual’s ventricle is? ...

    Correct

    • The average end diastolic volume in a healthy individual’s ventricle is?

      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
      4.8
      Seconds

  • Question 17 - What is troponin? ...

    Correct

    • What is troponin?

      Your Answer: A component of thin filaments

      Explanation:

      Skeletal muscle cytoplasmic proteins include myosin and actin (also known as thick and thin filaments, respectively) which are arranged in a repeating unit called a sarcomere. Troponin is a component of thin filaments (along with tropomyosin), and is the protein to which calcium binds.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.3
      Seconds

  • Question 18 - 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: Promotes smooth muscle contraction opening 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
      14.7
      Seconds

  • Question 19 - 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
      2.2
      Seconds

  • Question 20 - 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 ejection fraction is about 55%

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

      Explanation:

      The mitral valve closes during the phase of isovolumetric contraction. After atrial systole blood is pumped into the ventricles. When the ventricles begin to contract the pressure in the ventricles increases enough to close the mitral valve but not to open the aortic and pulmonary valves. During this phase the volume remains constant but the pressure continues to increase.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      52.2
      Seconds

  • Question 21 - 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
      17.5
      Seconds

  • Question 22 - The following is true of the sinus node: ...

    Incorrect

    • The following is true of the sinus node:

      Your Answer: It discharges at a rate of 80-100 bpm

      Correct Answer: It generates impulses automatically & at a quicker rate than other cardiac cells

      Explanation:

      The SA node exhibits automaticity. It generates the impulses to which the heart beats. It fires at a faster speed than the rest of the nervous components of the heart i.e. the AV nodes, purkinje fibers. This is the reason when the SA node fails the heart beats to the rhythm of the AV node.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.4
      Seconds

  • Question 23 - Initial depolarization of cardiac muscle is due to influx of: ...

    Correct

    • Initial depolarization of cardiac muscle is due to influx of:

      Your Answer: Na+

      Explanation:

      Initial depolarization of the cardiac muscle results from opening of the sodium voltage gated channels. This results in the influx of sodium and an increase in the membrane potential towards threshold. Potassium efflux results in repolarization.

      The cardiac action potential has 5 phases:

      • Phase 0—depolarization because of the opening of fast sodium channels. Potassium flux also decreases.
      • Phase 1—partial repolarization because of a rapid decrease in sodium ion passage as fast sodium channels close.
      • Phase 2—plateau phase in which the movement of calcium ions out of the cell, maintains depolarization.
      • Phase 3—repolarization, sodium, and calcium channels all close and membrane potential returns to baseline.
      • Phase 4—resting membrane potential (−90 mV), resulting from the activity of the Na+/K+ ATPase pump which creates a negative intracellular potential because of the exchange of three sodium ions for only two potassium ions.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      2.3
      Seconds

  • Question 24 - The SA and AV nodes are usually supplied by which artery? ...

    Correct

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

      Your Answer: Right coronary artery

      Explanation:

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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.3
      Seconds

  • Question 25 - 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
      30.5
      Seconds

  • Question 26 - When is the blood pressure at its lowest during pregnancy? ...

    Correct

    • When is the blood pressure at its lowest during pregnancy?

      Your Answer: Second trimester

      Explanation:

      It is lowest during the second trimester.

      Previous studies have reported changes in blood pressure (BP) throughout pregnancy, and it was generally accepted that in clinically healthy pregnant women, BP falls gradually at first trimester, reaching the lowest around 22–24 weeks, rising again from 28 weeks, and reaching preconception levels by 36 weeks of gestation

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.8
      Seconds

  • Question 27 - With regards to the cardiac cycle which of the following is true ...

    Correct

    • With regards to the cardiac cycle which of the following is true

      Your Answer: Right atrial systole occurs before left atrial systole: as below

      Explanation:

      Cardiac cycle: The first event in the cycle is atrial depolarization (a P wave on the surface ECG) follows by RIGHT ATRIAL and then LEFT ATRIAL contraction. Ventricular activation (QRS) follows after a short interval (the PR interval). LEFT VENTRICULAR contraction starts shortly thereafter RIGHT VENTRICULAR contraction begins. At the end, the aortic valve closure is followed by pulmonary valve closure.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.9
      Seconds

  • Question 28 - Cholinergic vagal supply to the SA and AV nodes results in slowing of...

    Correct

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

      Your Answer: M2 muscarinic receptors

      Explanation:

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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.2
      Seconds

  • Question 29 - Which of the following regulates the calcium release channels? ...

    Incorrect

    • Which of the following regulates the calcium release channels?

      Your Answer: Troponin c

      Correct Answer: Calstabin 2

      Explanation:

      Ca2+ is released from the SR through a Ca2+ release channel, a cardiac isoform of the ryanodine receptor (RyR2), which controls intracytoplasmic [Ca2+] and, as in vascular smooth-muscle cells, leads to the local changes in intracellular [Ca2+] called calcium sparks. A number of regulatory proteins, including calstabin 2, inhibit RyR2 and, thereby, the release of Ca2+ from the SR.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      12.2
      Seconds

  • Question 30 - 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: None of the above

      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
      20.4
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (22/30) 73%
Medicine (22/30) 73%
Passmed
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