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Which event causes the AV valves to close?

when ventricular pressure becomes greater than aortic pressure

when the semilunar valves open

when atrial pressure becomes greater than ventricular pressure

when ventricular pressure becomes greater than atrial pressure

when aortic pressure becomes greater than ventricular pressure

Which one of the following would cause a decrease in cardiac output?

Increased preload of cardiac muscle cells due to increased venous return.

Increased sympathetic nervous system activation.

Increased afterload on the heart.

❌✨

Increased contractility of the cardiac muscle.

Which electrical event directly causes mechanical events that decrease ventricular pressure?

T wave

QRS complex

❌✨

P wave

Why is the delay of action potential conduction at the AV node crucial to normal heart function?

It allows the atria to contract before the ventricles depolarize and contract.

It decreases the pressure generated in the right side of the heart.

It prevents heart murmurs (valve dysfunction).

It prevents the atria from contracting.

Which one of the following events occurs at the same time that the atria of the heart are contracting and pushing blood into the ventricles?

The semilunar valves are open.

The ventricles are in diastole.

Atrial pressure is less than ventricular pressure.

The AV valves are closed.

In contractile cardiac muscle cells, called cardiac myocytes, the plateau phase of the action potential is due to:

potassium movement out of the cardiac myocytes

calcium movement out of the cardiac myocytes

sodium movement into the cardiac myocytes

sodium movement out of the cardiac myocytes

potassium movement into the cardiac myocytes

calcium movement into the cardiac myocytes

✅✨

Increased contractility of the heart muscle increases cardiac output by:

decreasing end-systolic volume (ESV)

✅✨

decreasing end-diastolic volume (EDV)

decreasing heart rate

decreasing stroke volume

If venous return to the heart increases, what effect does this directly have on end-diastolic volume (EDV) and preload?

Increased venous return increases EDV but decreases the preload of the heart.

Increased venous return decreases EDV but increases the preload of the heart.

Increased venous return increases both EDV and preload of the heart.

Increased venous return decreases both EDV and preload of the heart.

Which type of circulatory shock results from extreme vasodilation due to the presence of bacterial toxins causing inadequate circulation of blood throughout the body?

cardiogenic shock

hypovolemic shock

neurogenic shock

septic shock

anaphylactic shock