Cardiovascular Physiology Quiz
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Questions and Answers

What is the name given to the initial phase of diastole characterized by rapid filling of the ventricles?

  • Rapid filling phase (correct)
  • Atrial systole
  • Isovolumetric relaxation
  • Diastasis

During which phase of diastole does only a small amount of blood flow into the ventricles?

  • Isovolumetric contraction
  • Initial rapid filling phase
  • Atrial contraction
  • Middle third of diastole (correct)

What percentage of the diastolic phase does the rapid filling phase occupy?

  • One-fourth
  • One-third (correct)
  • Two-thirds
  • One-half

Which of the following statements is true about the series of phases during diastole?

<p>The rapid filling phase occurs at the start of diastole (D)</p> Signup and view all the answers

What is the significance of the rapid filling phase in the cardiac cycle?

<p>It is essential for ensuring adequate ventricular filling (C)</p> Signup and view all the answers

What occurs during the period following the closure of the valves in the ventricles?

<p>Ventricular pressure drops rapidly. (A)</p> Signup and view all the answers

When does the ventricular pressure begin to rise again after it has dropped?

<p>When the ventricular pressure falls below atrial pressure. (A)</p> Signup and view all the answers

What ends the rapid drop in ventricular pressure?

<p>The A-V valves open for ventricular filling. (D)</p> Signup and view all the answers

What is the relationship between ventricular pressure and atrial pressure during this process?

<p>Ventricular pressure must fall below atrial pressure for A-V valves to open. (B)</p> Signup and view all the answers

What happens immediately after the A-V valves open?

<p>The ventricles become filled with blood. (C)</p> Signup and view all the answers

What physiological event primarily takes place during diastole?

<p>Most of the ventricular filling occurs (C)</p> Signup and view all the answers

Which statement is true regarding the resting phase of the heart muscle?

<p>The heart muscle is relaxed and receives blood (A)</p> Signup and view all the answers

How does diastole affect ventricular filling dynamics?

<p>It enhances filling by allowing prolonged rest (B)</p> Signup and view all the answers

In what phase of the cardiac cycle does the heart experience its maximum rest?

<p>Diastole (B)</p> Signup and view all the answers

What is the significance of ventricular filling during diastole?

<p>It is essential for maintaining systemic circulation (D)</p> Signup and view all the answers

What occurs first at the start of phase II isovolumetric ventricular contraction?

<p>The A-V valves close (D)</p> Signup and view all the answers

During isovolumetric contraction, what happens to the ventricular muscle length?

<p>It initially shortens relatively little (D)</p> Signup and view all the answers

What primarily causes the rise in intra-ventricular pressure during this phase?

<p>Myocardium pressing on the blood in the ventricle (A)</p> Signup and view all the answers

What is the state of the valves during isovolumetric ventricular contraction?

<p>Both A-V and semilunar valves are closed (D)</p> Signup and view all the answers

Which of the following best describes the phase immediately preceding isovolumetric contraction?

<p>Ventricular filling (B)</p> Signup and view all the answers

What is the time frame during which contraction occurs in single muscle fibers relative to depolarization and repolarization?

<p>Starts just after depolarization and lasts 50 ms after repolarization (D)</p> Signup and view all the answers

Which statement correctly describes the relationship between repolarization and contraction duration in single muscle fibers?

<p>Contraction lasts until repolarization is complete plus an additional 50 ms (B)</p> Signup and view all the answers

At what moment does contraction in single muscle fibers begin?

<p>Just after depolarization (C)</p> Signup and view all the answers

How long after repolarization is contraction said to last in single muscle fibers?

<p>50 ms (D)</p> Signup and view all the answers

What event marks the beginning of contraction in single muscle fibers?

<p>Depolarization (A)</p> Signup and view all the answers

What is the frequency range of the first heart sound?

<p>25-45 Hz (B)</p> Signup and view all the answers

What primarily causes the second heart sound to be louder and sharper?

<p>Elevated diastolic pressure in the aorta or pulmonary artery (A)</p> Signup and view all the answers

Why does the first heart sound have a lower frequency than the second heart sound?

<p>It reflects the tautness and greater elasticity of the arteries. (C)</p> Signup and view all the answers

What characteristic of the second heart sound is influenced by the valve closure dynamics?

<p>The sharpness is due to rapid closure during high pressure. (C)</p> Signup and view all the answers

At what point in the cardiac cycle does the second heart sound occur?

<p>At the end of systole (B)</p> Signup and view all the answers

Flashcards

Rapid Filling Phase

The first third of diastole when the ventricles fill rapidly with blood.

Slow Filling Phase

The middle third of diastole when only a small amount of blood enters the ventricles.

Diastole

The period of time when the heart chambers relax and refill with blood.

Ventricles

The lower chambers of the heart that pump blood to the lungs and body.

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Systole

The period of time when the heart chambers contract and pump blood out.

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Muscle Fiber Contraction Duration

The period when a single muscle fiber contracts, starting after depolarization and lasting until about 50ms after repolarization.

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Depolarization

The electrical signal traveling along the muscle fiber's membrane.

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Repolarization

The return of the membrane to its resting electrical state.

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Muscle Fiber

A single, independent unit of muscle tissue capable of contracting.

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Contraction

The shortening or tightening of a muscle fiber.

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Isovolumetric ventricular contraction

The initial stage of ventricular contraction where the ventricle is closed and the pressure inside increases.

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Ventricular Systole

The period when the heart's ventricles contract and pump blood out.

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A-V valves

The valves between the atria and ventricles, which close at the start of ventricular contraction.

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Intra-ventricular pressure

The amount of force the ventricles exert on the blood during contraction.

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Myocardium

The muscular wall of the heart that contracts to pump blood.

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Rapid Pressure Drop

The point in the cardiac cycle where ventricular pressure rapidly drops as soon as the heart valves close.

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Ventricular Pressure Drop Below Atrial Pressure

The point in the cardiac cycle where ventricular pressure falls below atrial pressure, causing the A-V valves to open and the ventricles to fill with blood.

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Early Diastole

The period following ventricular systole when the ventricles relax and start filling with blood.

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Ventricular Filling

The part of diastole where the ventricles fill with blood, starting from the moment the A-V valves open.

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Second Heart Sound

The sound produced by the closure of the aortic and pulmonic valves at the end of systole, marking the beginning of diastole.

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First Heart Sound

The sound produced by the closure of the mitral and tricuspid valves at the beginning of systole, marking the end of diastole.

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Elevated Diastolic Pressure and Second Heart Sound

The higher pressure in the aorta or pulmonary artery during diastole causes the valves to close more forcefully, producing a louder and sharper second heart sound.

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First Heart Sound Frequency

The first heart sound has a lower frequency (pitch) than the second heart sound due to the greater tautness and elasticity of the arteries.

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Study Notes

Cardiovascular Physiology

  • Cardiac Cycle: A cyclical sequence of events from the start of one heartbeat to the next. It includes diastole (relaxation) and systole (contraction).

  • Electrical Activity: Depolarization triggers a contraction wave throughout the myocardium, lasting about 50ms after repolarization.

  • Cardiac Cycle Phases (Left Ventricle):

    • Phase I (Filling): Blood passively flows into the ventricles due to atrial pressure buildup. Most of ventricular filling occurs during this phase.
    • Phase II (Isovolumetric Contraction): Ventricular pressure increases while the AV valves remain closed, leading to a short period before ejection.
    • Phase III (Ejection): Ventricular pressure surpasses aortic/pulmonary artery pressures, opening the semilunar valves for rapid expulsion.
    • Phase IV (Isovolumetric Relaxation): Ventricular pressure falls below the aortic/pulmonary pressures, causing valve closure and a subsequent decrease in pressure. This marks the end of systole and the start of filling.

  • Mechanical Events: Left ventricle events are used to depict all cardiac cycle events.

  • End Diastolic Volume (EDV): Blood volume in the ventricle at the end of diastole (filling).

  • End Systolic Volume (ESV): Blood volume in the ventricle at the end of systole (ejection).

  • Stroke Volume (SV): Blood ejected from the ventricle per contraction (EDV-ESV).

  • Ejection Fraction (EF): The percentage of end diastolic volume ejected (SV/EDV). Normal EF is ~65% for the left ventricle and ~45% for the right ventricle.

  • Heart Sounds: Generated by the vibrations of heart valves and tissue during contraction and relaxation.

    • First Heart Sound (S1): Caused by the closure of atrioventricular valves (AV valves).
    • Second Heart Sound (S2): Caused by the closure of semilunar valves (aortic and pulmonary).

  • Third Heart Sound (S3): Sometimes present in healthy, young adults or children, but can be associated with pathologies in older or diseased individuals.

  • Fourth Heart Sound (S4): Often pathologic, related to ventricular resistance or stiffness.

  • Murmurs/Bruits: Abnormal heart sounds indicating potential valve issues or other vascular problems.

Case Scenario (Page 6-7)

  • Patient Profile: A 60-year-old male with hypertension, palpitations, and shortness of breath, exhibiting a heart rate of 125 beats per minute.

  • Questions:

    • Which part of the cardiac cycle (systole or diastole) is primarily affected by a high heart rate?
    • How does a high heart rate impact LV end-diastolic volume and stroke volume?
    • Is there a heightened chance of a fourth heart sound (S4) and why?

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Related Documents

Cardiovascular Physiology Lecture 2 PDF

Description

Test your knowledge on the cardiac cycle and its phases in cardiovascular physiology. Explore the electrical activity and the sequence of events during a heartbeat, from contraction to relaxation. Understand the dynamics of the left ventricle and the flow of blood during each phase.

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