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.
Norepinephrine is a neurotransmitter secreted by neurons in the sympathetic nervous system. This chemical is secreted in response to stress, which triggers the 'fight or flight response.' The release of norepinephrine causes several changes that help our body to work more efficiently.
Norepinephrine. In addition to epinephrine, we see norepinephrine, which is a second hormone secreted by the adrenal medulla that increases heart rate, blood pressure, cardiac output and blood glucose levels.So we see that norepinephrine is very similar to epinephrine.t the center of the adrenal glands we see the adrenal medulla. This portion of the gland is stimulated by the sympathetic nervous system to secrete catecholamines, which are hormones that help you deal with short-term stress. There are two catecholamines. One is called epinephrine or adrenaline.