18. The Heart

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

The amount of blood in the ventricles at the end of the ventricular filling phase is the end-systolic volume.

Mr. Watson has been diagnosed with mitral insufficiency, or a malfunctioning mitral valve, which causes the valve to not close properly. Predict the signs and symptoms you might expect from a disease of this valve. What would happen to the patient's stroke volume and cardiac output? Explain. What might help improve his cardiac output?

Two elements determine blood pressure—the cardiac output of the heart and the peripheral resistance, or friction, in the blood vessels. Name two factors that increase cardiac output. Name two factors that increase peripheral resistance.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Tissue perfusion to the heart decreases during systole and increases during diastole.

Gabriel, a heroin addict, feels tired, is weak and feverish, and has vague aches and pains. Terrified that he has AIDS, he goes to a doctor and is informed that he is suffering not from AIDS, but from a heart murmur accompanied by endocarditis. What is the most likely way that Gabriel contracted endocarditis? (Hint: See Related Clinical Terms.)

Select the anatomical or physiological feature that correctly describes cardiac muscle and not skeletal muscle.

(a) striations appear as alternating light and dark bands,

(b) intercalated discs connect adjacent muscle cells,

(c) sarcoplasmic reticulum stores and releases calcium ions,

(d) calcium ions bind troponin to signal contraction

The cardiac term that refers to the volume of blood remaining in a ventricle after contraction is

(a) end diastolic volume,

(b) end systolic volume,

(c) stroke volume,

(d) cardiac reserve.