A&P Practice Quiz Unit 4

The life span of an erythrocyte is about _________ days.

120

The plateau phase of an action potential

allows cardiac muscle cells to contract and then relax without locking up.

The inferior, conical end of the heart is called the

apex

Gas, nutrient, and waste exchange occur between the __________ and the tissues of the body.

capillaries

The function of the postcapillary venule is to

drain the capillary bed.

The largest arteries of the body are classified as

elastic arteries.

As with action potentials in other types of cells, the repolarization of cardiac muscle cells involves the

exit of potassium through voltage-gated channels.

In young children, hematopoiesis occurs in most of their bones, but in adulthood it primarily occurs in

flat bones of the axial skeleton.

A portal system

is one in which blood flows through two capillary beds before being sent back to the heart.

Old erythrocytes are phagocytized in the

liver and spleen.