Use this information to respond to the following questions.
Humans have receptors for two kinds of beta adrenergic compounds such as catecholamines to control cardiac muscle contractions. Some are beta 1 receptors that promote increased heart rate. Other drugs, called beta blockers, slow heart rate. Smooth muscle cells, however, have beta 2 receptors, which mediate muscle relaxation. Blockers of these effects are sometimes used to treat asthma.
-The description above illustrates which of the following?
A) Just because a drug acts on one type of receptor does not mean that it will act on another type.
B) Beta blockers can be used effectively on any type of muscle.
C) Beta adrenergic receptors must be in the cytosol if they are going to influence contraction and relaxation.
D) The chemical structures of the beta 1 and beta 2 receptors must have the same active sites.

Question

Quizplus · Accepted Answer

The passage emphasizes how beta adrenergic compounds affect different types of muscle cells in different ways, depending on the type of beta receptor involved. This suggests that just because a drug is a beta blocker does not necessarily mean that it will have the same effect on all types of muscle cells.

Use This Information to Respond to the Following Questions