When epinephrine binds to cardiac (heart) muscle cells, it speeds their contraction. when it binds to muscle cells of the small intestine, it inhibits their contraction. how can the same hormone have different effects on muscle cells? a. cardiac cells have more receptors for epinephrine than do intestinal cells
b. epinephrine circulates to the heart first and is in higher concentration around cardiac cells
c. the two types of muscle cells have different signal transduction pathways for epinephrine and thus have different cellular responses
d. cardiac muscle is stronger than intestinal muscle and thus has a stronger response to epinephrine
e. epinephrine binds to g-protein-linked receptors in cardiac cells, and these receptors always increase a response to the signal. epinephrine binds to receptor tyrosine kinases in intestinal cells, and these receptors always inhibit a response to the signal