If the pacemaker cells in the SA note become more permeable to potassium ions, the

The pulmonary arteries carry blood to the

In response to hemorrhage, there is

An increased firing of the parasympathetic nervous system causes increased cardiac output.

Generalized vasoconstriction occurs as a result of:

The _____ _____ normally establish the rate of contraction

The mitral valve is normally closed:

Figure 20-2 Cardiac Cycle Use Figure 20-2 to answer the following questions: What occurs at the area labeled “B” on the graph?

The ________ covers the outer surface of the heart.

Vickie has a tumor that secretes excess amounts of the hormone aldosterone. Because of the elevated level of hormone, she exhibits