The head of a Roman snail, four tentacles well visible. [RN] Observing a snail crawling around, the view is immediately attracted by its head, orienting itself in its surroundings using the tentacles. The snail feels its environment, touches an obstacle and withdraws the tentacle.
One of these hormones is epinephrine, which can be defined as a hormone secreted by the adrenal medulla in response to short-term stress. Epinephrine is also called adrenaline, and you may have heard of this term before.
Like the postganglionic neurons of the sympathetic ganglia, cells in the adrenal medulla release norepinephrine (but they also release epinephrine). In this case, epinephrine and norepinephrine are considered hormones because they are released to the circulation.However they both bind to adrenergic receptors, and thus have much the same physiological effects as sympathetic neural stimulation.n this case, epinephrine and norepinephrine are considered hormones because they are released to the circulation. However they both bind to adrenergic receptors, and thus have much the same physiological effects as sympathetic neural stimulation.