Peripherial Neurology
The ( ortho- ) sympathetic nervous system ( SNS ) is one of three major parts of the autonomic nervous system : the others being the enteric and parasympathetic systems.
Sympathetic nervous system
The adrenergic receptors (or adrenoceptors ) are a class of G protein-coupled receptors that are targets of the catecholamines , especially norepinephrine (noradrenaline) and epinephrine (adrenaline). Many cells possess these receptors, and the binding of a catecholamine to the receptor will generally stimulate the sympathetic nervous system .
Adrenergic receptor
Norepinephrine ( INN ) (abbreviated norepi or NE ), or noradrenaline ( BAN ) (abbreviated NA , NAd , or norad ), is a catecholamine with multiple roles including as a hormone and a neurotransmitter . [ 3 ] Areas of the body that produce or are affected by norepinephrine are described as noradrenergic .
Norepinephrine
Epinephrine
Epinephrine (also known as adrenaline or adrenalin ) is a hormone and a neurotransmitter . [ 1 ] Epinephrine has many functions in the body, regulating heart rate , blood vessel and air passage diameters, and metabolic shifts; epinephrine release is a crucial component of the fight-or-flight response of the sympathetic nervous system . [ 2 ] In chemical terms, epinephrine is one of a group of monoamines called the catecholamines .
Pheochromocytoma
A pheochromocytoma (Etymology: Greek "phaios =dark, chroma = color, kytos =cell, oma = tumor") or phaeochromocytoma ( PCC ) is a neuroendocrine tumor of the medulla of the adrenal glands (originating in the chromaffin cells ), or extra-adrenal chromaffin tissue that failed to involute after birth [ 1 ] and secretes high amounts of catecholamines , usually noradrenaline ( norepinephrine ), and adrenaline ( epinephrine ) to a lesser extent. [ 2 ] Extra-adrenal paragangliomas (often described as extra-adrenal pheochromocytomas) are closely related, though less common, tumors that originate in the ganglia of the sympathetic nervous system and are named based upon the primary anatomical site of origin.
