Identify the structures in the following diagram of a sectional view of the heart. a. ___b. ___c. ___d. ___e. ___f. ___g. ___h. ___i. ___j. ___k. ___l. ___m. ___

If the papillary muscles fail to contract, (a) the ventricles will not pump blood, (b) the atria will not pump blood, (c) the semilunar valves will not open, (d) the AV valves will not close properly, (e) none of these happen.

The refractory period of cardiac muscle is much longer than that of skeletal muscle. Why is this a desirable functional property?

After Randy was diagnosed with stomach cancer, nearly all of his stomach had to be removed. Postoperative treatment included regular injections of vitamin B12. Why was this vitamin prescribed, and why were injections specified?

How does the heart's ability to contract differ from that of other muscles of the body?

The serous membrane covering the outer surface of the heart is the (a) parietal layer of the serous pericardium,(b) endocardium, (c) myocardium, (d) visceral layer of the serous pericardium.

The simple squamous epithelium covering the heart valves is the (a) epicardium, (b) endocardium, (c) myocardium, (d) endothelium.

Describe the three distinct layers that make up the heart wall.