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 Epinephrine. Norepinephrine, also known as noradrenaline, is a neurotransmitter found in the sympathetic nervous system. The sympathetic nervous system stimulates the heart, blood vessels, sweat glands, the large internal organs, and the adrenal medulla in the brain.he amino acid tyrosine, found in high concentrations in cheese, is converted by specific reactions into at least two neurotransmitters â norepinephrine and dopamine. Norepinephrine is produced from dopamine, with the help of the amino acids phenylalanine, lysine, and methionine.