Anatomy & Physiology II: Heart and Cardiovascular System

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.

isovolumetric contraction, ventricular ejection, isovolumetric relaxation

Cardiac muscle cells are __________.

mechanically, chemically, and electrically connected to one another

Which structure provides a rapid-conduction path that tenses the papillary muscles before the ventricular myocardium contracts, preventing "slamming" of the right AV cusps?

moderator band

Which of the following statements most accurately defines what is happening during the second phase of ventricular systole of the cardiac cycle?

Blood is being ejected from the ventricles through open semilunar valves.

In an ECG recording, which of the following coincides with ventricular repolarization?

T wave

Which statement is correct regarding the intrinsic heart rate?

During parasympathetic stimulation, acetylcholine released by parasympathetic neurons opens chemically gated potassium channels in the plasma membrane.

Which of the following is correct about the filling of the ventricles?

Most blood flows passively into the ventricles through open AV valves.

In the non-exercising heart, which event of the cardiac cycle lasts the longest?

atrial diastole

Increased pressure in the ventricles would close what valve(s)?

AV valves only

Which event does NOT happen during ventricular diastole?

Atrioventricular valves close because of the contracting ventricles.

Which of the following statements is correct concerning the cardiac cycle?

In late ventricular diastole, all chambers are relaxed and filling to about seventy percent of their capacity.

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.

Pressure in the atria would be greater than the pressure in the ventricles.

The portion of the tracing of an electrocardiogram, ECG, that represents ventricular depolarization is the __________.

QRS complex

What causes the aortic semilunar valve to close?

greater pressure in the aorta than in the left ventricle

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.

ventricular diastole