PAM 600 Cardiovascular Physiology

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Questions and Answers

What is the primary reason for the interdependence of the outputs of the left and right ventricles?

Both ventricles pump blood into the same circulatory system. (correct)

Right ventricle output is unaffected by left ventricle performance.

The atria control the output of each ventricle independently.

The left ventricle regulates blood flow to the aorta exclusively.

Which of the following factors does NOT affect vascular resistance?

Platelet count (correct)

Blood viscosity

Vessel length

Vessel diameter

Which aspect of cardiac physiology is primarily responsible for generating the pressure needed for blood flow?

Pacemaker cell activity

Cardiac muscle elasticity

Cardiac output variability

Interventricular pressure differences (correct)

Which of the following best describes the function of hemodynamics in the cardiovascular system?

It encompasses the forces involved in blood circulation. Signup and view all the answers

Which statement about the cardiac cycle is accurate?

Diastole allows the heart chambers to fill with blood. Signup and view all the answers

Where is the site of highest vascular resistance in the systemic circulation?

Arterioles Signup and view all the answers

What happens to mean arterial pressure if both cardiac output and total peripheral resistance (TPR) increase?

It increases Signup and view all the answers

Which factor contributes to blood viscosity the most?

RBC count and albumin concentration Signup and view all the answers

How does blood pressure change as it flows through the systemic vasculature?

It decreases until it reaches the veins Signup and view all the answers

What effect does anemia have on blood flow?

Speeds up blood flow Signup and view all the answers

What does compliance refer to in the context of blood vessels?

The volume change produced by a given pressure change Signup and view all the answers

Which condition would likely slow down blood flow due to increased viscosity?

Polycythemia Signup and view all the answers

What primarily causes blood pressure to decline as it moves from arteries to veins?

Friction between blood and vessel walls Signup and view all the answers

What is the primary purpose of the long refractory period in cardiac muscle tissue?

To allow for diastole and prevent tetany Signup and view all the answers

Which of the following is NOT a variable associated with the cardiac cycle?

Diastolic pressure Signup and view all the answers

How does myocardial contractility affect stroke volume in the presence of increased afterload?

It can compensate for reduced preload to maintain stroke volume Signup and view all the answers

In what way does Starling's law help maintain cardiac output?

By matching output of the right and left ventricles according to volume Signup and view all the answers

What effect does increased heart rate have on stroke volume, according to the reciprocal relationship in cardiac output?

It may decrease stroke volume if too high Signup and view all the answers

Which factor is primarily altered to affect cardiac output through ventricular filling changes?

Changes in end-diastolic volume Signup and view all the answers

Which statement about preload and afterload is accurate in the context of contractility?

Increased afterload can negatively impact contractility Signup and view all the answers

Which of the following statements accurately describes hemodynamic variables associated with the cardiac cycle?

Afterload is the resistance the heart must overcome to eject blood Signup and view all the answers

What mechanism is responsible for contraction in cardiac muscle?

Sliding filament mechanism Signup and view all the answers

Which structure acts as the normal pacemaker of the heart?

SA node Signup and view all the answers

What is the typical resting heart rate of a person with enhanced parasympathetic tone, like that of an endurance athlete?

70 beats/min Signup and view all the answers

What happens if the SA node fails or transmission to the AV node fails?

AV node takes over as the pacemaker Signup and view all the answers

Which statement about cardiac action potentials is true?

No stimulus can produce another action potential during the effective refractory period. Signup and view all the answers

What could happen due to arrhythmias in the heart?

Inappropriate heartbeats Signup and view all the answers

What is the intrinsic firing rate of the SA node under normal conditions?

100 beats/min Signup and view all the answers

If the ventricular rate is excessive, what is the main consequence?

Insufficient time between beats for filling Signup and view all the answers

What does the cardiac cycle specifically refer to?

The complete contraction and relaxation of all four chambers of the heart Signup and view all the answers

In terms of the cardiac cycle, what do the terms systole and diastole primarily refer to?

Contraction and relaxation of the ventricles respectively Signup and view all the answers

Which of the following statements about stroke volume (SV) is correct?

SV is calculated by subtracting end systolic volume from end diastolic volume Signup and view all the answers

What is the average cardiac output (CO) for an adult?

5 L/min Signup and view all the answers

Which factor can decrease cardiac output (CO)?

Decreased heart rate Signup and view all the answers

What determines ejection fraction?

The fraction of blood ejected from the ventricle during systole Signup and view all the answers

What is the relationship between the electrical events and mechanical events in the cardiac cycle?

Electrical events precede mechanical events Signup and view all the answers

Which measurement can be used to assess cardiac performance?

Ejection fraction Signup and view all the answers

Study Notes

Cardiovascular System Overview

The cardiovascular system is central to medical physiology, focusing on hemodynamics and the functional organization of blood flow.
The outputs of the left and right ventricles are interdependent, highlighting their collaborative function in blood circulation.

Hemodynamics

Mean arterial pressure is influenced by cardiac output and total peripheral resistance (TPR).
Blood pressure decreases as it travels through the circulatory system, with the largest drop occurring across arterioles due to high vascular resistance.

Factors Affecting Blood Flow

Vessel length impacts blood pressure; longer vessels result in greater pressure loss due to friction.
Blood viscosity is affected primarily by red blood cell count and albumin concentration, influencing flow rates under various conditions (e.g., anemia vs. polycythemia).
Compliance refers to the distensibility of blood vessels; low compliance means a minimal volume change for a given pressure change.

Cardiac Electrophysiology

The sinoatrial (SA) node serves as the primary pacemaker, firing at about 100 beats/min, moderated to around 70 beats/min due to parasympathetic tone.
The atrioventricular (AV) node can act as a backup pacemaker in case the SA node fails, often resulting in a slower heart rate.

Cardiac Cycle

The cardiac cycle consists of systole (contraction) and diastole (relaxation) phases, with electrical events always preceding mechanical actions.
Mechanical events correlate with ECG waves, illustrating the relationship between electrical signals and heart muscle contraction.

Cardiac Output and Stroke Volume

Cardiac output (CO) is calculated as the product of heart rate (HR) and stroke volume (SV), averaging around 5 L/min in adults.
Stroke volume is determined by the difference between end-diastolic volume (EDV) and end-systolic volume (ESV).

Ejection Fraction

Ejection fraction measures the percentage of blood ejected from the ventricles during contraction, indicating ventricular performance.

Regulatory Mechanisms

Calcium regulatory mechanisms in myocardial cells affect the inotropic state, influencing the strength of cardiac contractions.
Frank-Starling principle illustrates how changes in preload and afterload impact cardiac output and overall heart function.

Refractory Periods

Cardiac action potentials feature long refractory periods, preventing tetany and ensuring adequate filling time during diastole.

Summary of Key Factors

Understanding the dynamics of blood flow, pressure, and heart function is essential for comprehending cardiovascular physiology.
Knowledge of how various parameters like vessel length, viscosity, and compliance influence hemodynamics is critical for medical practice.

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Description

Explore the intricate details of the cardiovascular system in this quiz designed for PAM 600. Review key concepts in human anatomy and physiology with a focus on cardiovascular physiology. Perfect for students looking to reinforce their understanding of this vital subject.