Question

How does norepinephrine from the sympathetic nervous system and adrenal medulla affect blood flow to tissues?

Answer 1

Norepinephrine is known as catecholamine and it functions like both hormons and neurotransmitter.Norepinephrin is produced from dopamine by enzyme dopamine beta hydroxylase in the secretory granules of medulla resident chromaffin cells and is released by Adrenal medulla in blood as a hormone.In the form of neurotransmitter it stays in CNS and sympathetic nervous system(SNS) and produced by nonadrenogenic neurons in locus coeruleus.

Norepinephrine usually get released from the sympathetic neurons and affects the heart function.The elevation in the release of norepinephrine from SNS increases the contraction process in the heart and initiate the release of glucose from energy stores and increses the blood flow to the tissues. As a hormone, it increases blood pressure by increasing vascular tone via alpha adrenergic receptor activation.