A&P Chapter 17

Which of the following is not part of the conduction system of the heart?

AV valve

The source of blood carried to capillaries in the myocardium would be the ________.

coronary arteries

Small muscle masses attached to the chordae tendineae are the ________.

papillary muscles

When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________.

noticing the thickness of the ventricle walls

Which vessel of the heart receives blood during right ventricular systole?

pulmonary trunk

The left ventricular wall of the heart is thicker than the right wall in order to ________.

pump blood with greater pressure

The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________.

pumps blood against a greater resistance

Isovolumetric contraction ________.

refers to the short period during ventricular systole when the ventricles are completely closed chambers

To auscultate the aortic semilunar valve, you would place your stethoscope in the ________.

second intercostal space to the right of the sternum

Which of the following factors does not influence heart rate?

skin color

During contraction of heart muscle cells ________.

some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores

The tricuspid valve is closed ________.

when the ventricle is in systole

As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.

True

Select the correct statement about cardiac output.

A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.

Damage to the ________ is referred to as heart block.

AV node

Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.

False

Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.

False

The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart's pulmonary and aortic valves.

False

Select the correct statement about the heart valves.

The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur.

Select the correct statement about the function of myocardial cells.

The entire heart contracts as a unit or it does not contract at all.

Select the correct statement about the structure of the heart wall.

The myocardium is the layer of the heart that actually contracts.

Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues.

True

The left side of the heart pumps the same volume of blood as the right.

True

The myocardium receives its blood supply from the coronary arteries.

True

Which of the events below does not occur when the semilunar valves are open?

Ventricles are in diastole.

Hemorrhage with a large loss of blood causes ________.

a lowering of blood pressure due to change in cardiac output

The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________

angina pectoris

The P wave of a normal electrocardiogram indicates ________.

atrial depolarization

During the period of ventricular filling ________.

blood flows passively through the atria and the open AV valves into the ventricles

Which of these vessels receives blood during ventricular systole?

both the aorta and pulmonary trunk

Norepinephrine acts on the heart by ________.

causing threshold to be reached more quickly

Normal heart sounds are caused by which of the following events?

closure of the heart valve

If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________.

decreased delivery of oxygen

Compared to skeletal muscle, cardiac muscle ________.

has gap junctions that allow it to act as a functional syncytium

The second heart sound is heard during which phase of the cardiac cycle?

isovolumetric relaxation

Blood within the pulmonary veins returns to the ________.

left atrium

The time of day most hazardous for heart attacks is ________.

morning

If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells ________.

tetanic contractions might occur, which would stop the heart's pumping action

If the vagal nerves to the heart were cut, the result would be that ________.

the heart rate would increase by about 25 beats per minute

Which of the following is not an age-related change affecting the heart?

thinning of the valve flaps

If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________.

threshold is reached more quickly and heart rate would increase