Chapter 28

From which vessels do myocardial cells receive blood?

Coronary arteries

A graphic record of the heart's electrical activity is a(n)

ECG

The type of membranous tissue that lines the heart and blood vessels is the

Endothelium

After blood leaves the lungs and returns to the heart, it enters the

Left atrium

The bulk of the heart wall is the thick, contractile middle layer called the

Myocardium

The free edges of the atrioventricular valves are anchored to the

Papillary muscles

Which division of the autonomic nervous system sends fibers to the heart?

Parasympathetic and sympathetic

The heart has its own special covering, a loose-fitting inextensible sac called the

Pericardium

Atria are often called ____ because they receive blood from vessels called veins.

Receiving chambers

The normal cardiac impulse that initiates mechanical contraction of the heart arises in the

SA node

The four structures that compose the conduction system of the heart are the

SA node, AV node, AV bundle, and purkinje fibers

The heart valves that are located where the trunk of the pulmonary artery joins the right ventricle and where the aorta joins the left ventricle are called

Semilunar valves

A normal ECG is composed of all of the following

T wave, P wave, QRS complex

A type of abnormal heart sound that may signify incomplete closing of the valves is

a heart murmur

Mechanical devices that permit the flow of blood in one direction only are called

valves