Chapter 21

Question 1

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

Answer 1

the right ventricle

Question 2

In what way does cardiac muscle differ from skeletal muscle?

Answer 2

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

Question 3

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

Answer 3

right ventricle Pulmonary trunk: A vessel that arises from the right ventricle of the heart, extends upward, and divides into the right and left pulmonary arteries that convey unaerated blood to the lungs.

Question 4

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

Answer 4

left atrium

Question 5

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

Answer 5

left atrium

Question 6

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

Answer 6

right atrium

Question 7

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

Answer 7

ventricular systole

Question 9

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

Answer 13

Question 14

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.

Answer 14

SA node; AV node

Question 15

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

Answer 15

Systole: high chamber pressure, blood ejected from ventricles, high arterial pressure

Diastole: low chamber pressure, blood filling ventricles, low arterial pressure

Question 16

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.

Answer 16

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

Question 17

The sinoatrial and atrioventricular nodes __________.

Answer 17

establish cycles of contraction and relaxation for the myocardium

Question 18

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

Answer 18

SA node