Module 26 Knowledge Check

Stroke volume x Heart Rate = ?

Cardiac output

The P wave on an ECG corresponds to:

Atrial depolarization

The pacemaker of the heart is:

SA Node

The T wave on an ECG corresponds to:

Ventricular repolarization

The QRS complex on an ECG corresponds to:

Ventricular depolarization

Total volume of blood in ventricles at end of diastole:

End diastolic volume

Sequence of events compromising one complete ventricular contraction and relaxation:

Cardiac cycle

Amount of blood ejected from each ventricle during systole (70 mis) is termed:

Stroke volume

Which of the following is NOT a ECG deflection wave?

PT wave

This portion of the electrical conduction system of the heart is located in the interventricular septum:

Bundle branches

During the period of atrial filling:

Blood is entering the atria

Activation of the parasympathetic nerve causes:

The heart to beat slower

During isovolumetric relaxation,

The AV and semilunar valves are closed and ventricular pressure is decreasing

What is occurring during ventricular ejection?

The AV valves are closed and the semilunar valves are open as blood is leaving the ventricles

Which of the following is TRUE of the ventricular filling phase of the cardiac cycle?

Ventricular pressure is less than aortic pressure

During which phase of the cardiac cycle are all four heart valves open?

None

The increase in ventricular volume early in diastole reflects the:

Passive movement of blood through the atrium and into the ventricle

The small increase in ventricular pressure observed late in diastole is caused by:

Atrial contraction

The end-diastolic volume minus the end-systolic volume is the:

Stroke volume

What causes the sounds that one hears as the heart beats?

The turbulence created as the valves close

Regulation of the heart (or any organ or tissue) by neural input, circulating hormones or any other factor originating from outside the organ is referred to as ________ control.

Extrinsic

Which of the following structures is poorly innervated by the parasympathetic nervous system and, therefore, an increase in parasympathetic activity has little effect on this structure?

Ventricles

What is cardiac output?

Stroke volume times heart rate

What is end-diastolic volume?

Amount of blood coming into the ventricles

What happens when the heart rate increases?

It increases cardiac output by increasing the number of cardiac volumes of blood

How is stroke volume determined?

Myocardial contractility

What is stroke volume?

Volume of blood that heart can contain and eject upon contraction

What is heart rate?

The number of "heart loads" of blood ejected per unit of time

What are the factors affecting cardiac output?

Heart rate, stroke volume

When does ventricular heart filling occur?

During Phase 6

What is isovolumetric relaxation?

When intraventricular pressure fall sufficiently at the end of phase four, the aortic and pulmonic valves abruptly close, causing the second heart sound and isovolumetric contraction

What is isovolumetric contraction?

During the period between the closure of the AV valves and opening of the aortic and pulmonic valves, ventricular pressure rises rapidly without a change in ventricular volume. No ejection occurs and ventricular volume doesn't change

What is the sixth phase of the cardiac cycle?

It is pumped through the aortic valve and into the aorta where it then goes off to the body

What is the fifth phase of the cardiac cycle?

It moves through the mitral valve and into the left ventricle

What is the fourth phase of the cardiac cycle?

Blood returns to the left atrium by way of the pulmonary vein

What is the third phase of the cardiac cycle?

The blood moves through the pulmonary valve, into the pulmonary arteries and through the capillaries of the lungs where it is oxygenated

What is the second phase of the cardiac cycle?

Heart muscle contraction is normally initiated by the action potentials originating in the SA node located in the upper right atrium

What is the first phase of the cardiac cycle?

Blood returns from the venous system and enters the right atrium. It moves through the tricuspid valve and into the right ventricle

When does heart filling occur?

During diastole

What is the meaning of diastole?

Ventricular relaxation

What is the meaning of systole?

Ventricular contraction

When do AV Valves open?

During ventricular diastoel

When do AV valves close?

During ventricular systole

What event forces the pulmonary and aortic valves (semilunar valves) to open?

Rising ventricular pressure forces semilunar valves open. Blood is ejected from the heart