first 25

Question 1

Contraction of any heart chamber is called

Answer 1

systole

Question 2

A persistent, resting heart rate in excess of 100 beats/minute is called

Answer 2

tachycardia

Question 3

If the SA node fails to function, other regions of atrial myocardium called ___ take over and trigger a rhythmic heartbeat, although at a slower rate.

Answer 3

ectopic pacemaker

Question 4

When the ventricles first begin to contract, there is not enough pressure in them to force the semilunar valves open, and for a moment, no blood is expelled. Therefore this phase of the cardiac cycle is called

Answer 4

Isovolumetric Contraction

Question 5

Each ventricle ejects about 75 ml of blood in one beat. This figure is called the

Answer 5

Stroke Volume

Question 6

The ventricles are said to exhibit _____ when they beat in a rapid, uncoordinated fashion or squirming motion and do not effectively eject blood.

Answer 6

Fibrillation

Question 7

The death of a patch of myocardium due to ischemia is clinically known as _____ and likely to cause a heart attack. It is sometimes mistakenly used as a synonym for heart attack.

Answer 7

Myocardial Infarction

Question 8

In the aortic arch and carotid arteries there are pressure sensors called _____, which help to monitor and regulate blood pressure.

Answer 8

Baroreceptors

Question 9

What are the three parts of the heart wall?

Answer 9

Myocardium / Endocardium / Epicardium

Question 10

An increased afterload reduces the heart’s ejection fraction.

Answer 10

True

Question 11

If the SA node is destroyed, the heart will stop beating.

Answer 11

False

Question 12

The first heart sound occurs at the same time as the P wave of the ECG.

Answer 12

False

Question 13

Being larger than the right ventricle, the left ventricle pumps more blood in each beat.

Answer 13

False

Question 14

The myocardium begins to relax at the end of the plateau in the action potential.

Answer 14

True

Question 15

Since athletes are in better than average condition, their hearts beat faster at rest.

Answer 15

False

Question 16

Cor pulmonale results when the left ventricle fails, causing blood to back up into the lungs.

Answer 16

False

Question 17

Cells of the SA node exhibit a long plateau in their action potentials.

Answer 17

False

Question 18

The parasympathetic nervous system has a negative chronotropic effect on the heart.

Answer 18

True

Question 19

The bundle of His originates at the AV node.

Answer 19

True

Question 20

The unusually long refractory period of the myocardium prevents wave summation and tetanic contraction.

Answer 20

False

Question 21

Papillary muscles help to prevent prolapse of the semilunar valves.

Answer 21

False

Question 22

The myocardium receives the least amount of blood when the ventricles are contracting.

Answer 22

True

Question 23

The resting heart rate would be slower if not for the fact that sympathetic nerve fibers continually stimulate it.

Answer 23

False

Question 24

Most blood enters the ventricles even before the atria begin to contract.

Answer 24

True

Question 25

The coronary arteries arise from

Answer 25

the proximal end of the aorta