Chapter 20 Open Book Assignment

An incompetent pulmonary semilunar valve could result in less blood reaching the

• lungs.

• heart muscle.

• right ventricle.

• aorta.

• right atrium.

Coronary artery disease can diminish myocardial blood flow resulting in the death of myocardial cells. This condition is known as a myocardial

• attack.

• angina.

• necrosis.

• cirrhosis.

• infarction.

Which of the following is mismatched?

• opening of sodium channels - depolarization

• closing of calcium channels - plateau phase

• opening of potassium channels - rapid repolarization

• closure of sodium channels - early repolarization

• opening of calcium channels - plateau phase

If cardiac muscle cells are unable to repolarize, this would cause

• cardiac output to increase.

• no harm. These cells can spontaneously depolarize anyway.

• the heart rate to decrease. It might cause cardiac arrest.

• an increased demand on mitochondria to produce more ATP.

• tachycardia.

In the cardiac cycle,

• the right atrium and the right ventricle contract simultaneously.

• the left atrium contracts before the right atrium.

• all four chambers of the heart contract at the same time.

• all four chambers of the heart are in diastole at the same time.

Pressure in the right ventricle must exceed pressure in the ____ before the right ventricle can eject blood.

• superior vena cava

• coronary sinus

• pulmonary trunk

• aorta

• pulmonary veins

What occurs during the time between the first heart sound and the second heart sound?

• ventricular systole

• ventricular diastole

• ventricular filling

• atrial systole

• the P wave of the ECG

The plateau phase seen during the action potential of a cardiac muscle cell is due to the

• sodium-potassium pump.

• opening of sodium channels.

• continuing to have open calcium channels.

• closure of chloride channels.

• closing of calcium channels.

What action is most responsible for the resting membrane potential in cardiac muscle cells?

• movement of K+ through voltage-gated K+ channels

• movement of Na+ through open Na+ channels

• movement of Ca2+ through voltage-gated Ca2+ channels.

• closing of Na+ and K+ voltage-gated channels

Aortic stenosis results from

• a hole in the interatrial septum.

• a weakening of heart muscle.

• a narrowed opening through the aortic valve.

• low oxygen levels.

• leakage from the AV valves.