Norepinephrine and epinephrine are considered to be ________ when released into the bloodstream,but ________ when released at synapses.
A)hormones; neurotransmitters
B)neuropeptides; neurotransmitters
C)neurotransmitters; hormones
D)neurotransmitters; neuropeptides
E)neuropeptides; neurohormones

Question

Quizplus · Accepted Answer

Norepinephrine and epinephrine are classified as hormones when they are released into the bloodstream and act on distant target cells. However, they are classified as neurotransmitters when they are released at synapses to act on adjacent cells.

Norepinephrine and Epinephrine Are Considered to Be ________ When Released