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 is also made in the adrenal medulla where it synthesized from dopamine and is released into the blood as a hormone. Epinephrine is made from norepinephrine inside the adrenal medulla (the inner part of the adrenal gland, a small gland associated with the kidneys). Our adrenal medulla helps us to cope with physical and emotional stress. The synthesis of epinephrine increases during times of stress.