Chapter 21

Damage to the internodal pathways would NOT affect the function of the __________.

SA node

How are chamber pressure, blood flow, and arterial pressure related to ventricular systole and diastole?

Systole: high chamber pressure, blood ejected from ventricles, high arterial pressure Diastole: low chamber pressure, blood filling ventricles, low arterial pressure

A blockage in the pulmonary trunk would first affect which heart chamber with a buildup of blood?

right ventricle

During which phase of the cardiac cycle would you find the atria empty?

ventricular systole

Oxygenated blood returns to the heart from the lungs and enters the __________.

left atrium

When blood leaves the lungs and returns to the heart, it enters the __________.

left atrium

Plaque buildup in the left coronary artery (LCA) would NOT affect which portion of the heart?

right atrium

Which of the heart's chambers is responsible for sending blood to the lungs to pick up oxygen?

the right ventricle

The __________ initiates the electrical impulse that triggers a heartbeat, while the __________ delays the spread of this impulse from the atria to the ventricles. This delay allows the ventricles to finish filling before they start to contract.

SA node; AV node

After studying the diagram "The Phases of the Cardiac Cycle," estimate the amount of time between the beginning of one heart beat to the next heart beat for which all heart muscle relaxes.

Both atria contract together. As the atria relax, both ventricles contract.

In what way does cardiac muscle differ from skeletal muscle?

Cardiac muscle relies heavily on aerobic respiration, whereas skeletal muscle can function for a time in anaerobic conditions.

The sinoatrial and atrioventricular nodes __________.

establish cycles of contraction and relaxation for the myocardium