Epinephrine and norepinephrine that are released from the adrenal glands affect target tissue for a longer period of time than the same substances released from neurons at their peripheral receptors. Why?
◦ The epinephrine and norepinephrine from the adrenal glands are released by sympathetic neurons, whereas parasympathetic neurons release these substances at the effector organs.
◦ The effectors are less sensitive to epinephrine and norepinephrine released by the adrenal glands.
◦ The adrenal gland releases larger amounts of the neurotransmitters than the neurons.
◦ There are no enzymes to break down epinephrine and norepinephrine in the blood and very little in peripheral tissues.
◦ The hormones released from the adrenal glands bind to different receptors than those released from neurons.
Endocrine Glands/Organ Functions
The endocrine glands.
The adrenal glands.
Parathyroid Glands
Salivary glands
Blood tissue