The portion of the intrinsic conduction system located in the superior interventricular septum is thea. AV node,b. SA node,c. AV bundle,d. subendocardial conducting network.

Cardiac muscle cells are joined by structures called:

a. T-tubules.

b. tight junctions.

c. sarcoplasmic reticulum.

d. intercalated discs.

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

e. The heart plays a role in the regulation of blood pressure and secretes the hormone atrial natriuretic peptide.