Question 1

The cardiac cycle is the sequence of events that occurs during:&#10;A) a 24-hour period.&#10;B) one heartbeat.&#10;C) one minute.&#10;D) a lifetime.

Accepted Answer

The cardiac cycle is the sequence of events that occurs during one heartbeat. A cardiac cycle is a coordinated contraction and relaxation of the chambers of the heart.

Question 2

Contractions of the heart muscle (myocardium), during which blood is pumped out of a chamber, is:&#10;A) heart rate.&#10;B) cardiac output.&#10;C) diastole.&#10;D) systole.

Accepted Answer

At the end of atrial systole, the ventricles contract; this is called ventricular systole. As ventricular contractions begin, blood is forced against the AV valves, causing them to snap shut.

Question 3

Relaxation of the myocardium is called:&#10;A) heart rate.&#10;B) cardiac output.&#10;C) diastole.&#10;D) systole.

Accepted Answer

The period of diastole therefore is a period of filling (of blood); atrial systole follows.

Question 4

The normal cardiac output is about 5 L/minute. If this is the case, how many minutes does it take to pump the entire blood volume of the body through the heart?&#10;A) one day&#10;B) one hour&#10;C) one minute&#10;D) one heartbeat

Accepted Answer

Cardiac output is the amount of blood pumped by the ventricle in 1 minute.

Question 5

Which of the following occurs during ventricular systole?&#10;A) Blood is pumped out of the ventricles.&#10;B) The ventricles fill with blood.&#10;C) The AV valves open.&#10;D) The semilunar valves close.

Accepted Answer

As ventricular contractions begin, blood is forced against the AV valves, causing them to snap shut. The blood pushes the semilunar valves open, allowing blood to flow into the pulmonary trunk and aorta.

Question 6

Which of the following increases stroke volume?&#10;A) (+) chronotropic effect&#10;B) (+) dromotropic effect&#10;C) decreased EDV&#10;D) (+) inotropic effect

Accepted Answer

A second way to increase stroke volume is by strengthening the force of myocardial contraction without stretching the myocardial fibers. This is called a positive inotropic effect.

Question 7

A drug, such as atropine, that blocks the muscarinic receptors is most likely to:&#10;A) induce a severe bradycardia.&#10;B) cause a (-) dromotropic effect, leading to heart block.&#10;C) increase heart rate.&#10;D) decrease cardiac output.

Accepted Answer

Atropine is an example of a muscarinic blocker that is often used to relieve bradycardia and heart block (slowing of the cardiac impulse through the heart).

Question 8

Which of the following does not affect a person's heart rate?&#10;A) a person's size&#10;B) the person's eye color&#10;C) gender&#10;D) age

Accepted Answer

Resting heart rates differ for many reasons, including size, gender, and age.

Question 9

What causes the left heart to fail?&#10;A) myocardial infarction and chronic hypertension&#10;B) blood backing up into the veins that return blood to the right heart&#10;C) jugular vein distention&#10;D) hepatomegaly

Accepted Answer

Two common causes of left hear failure are myocardial infarction (MI) and chronic hypertension (increased blood pressure).

Question 10

Which of the following is an age-related cardiac change?&#10;A) The resting heart rate increases to 90 beats/minute.&#10;B) Starling's law of the heart is lost.&#10;C) The sarcoplasmic reticulum loses its ability to store calcium.&#10;D) The heart muscle cannot respond as vigorously to the demands of exercise.

Accepted Answer

An age-related decline occurs in exercise cardiac output. The heart cannot respond as quickly or as forcefully to the increased workload of the exercised heart. Exertion, sudden movements, and changes in position may cause a decrease in cardiac output.

Deck 17: Function of the Heart