Sympathetic nervous system

organism's response to a stressor such as an environmental condition or a stimulus

one of two divisions of the autonomic nervous system, along with the parasympathetic nervous system

physiological reaction to a perceived threat or harmful event

part of the adrenal gland

paired bundle of nerve fibers that run from the base of the skull to the coccyx

Adrenergic means "working on adrenaline (epinephrine) or noradrenaline (norepinephrine)" (or on their receptors). When not further qualified, it is usually used in the sense of enhancing or mimicking the effects of epinephrine and norepinephrine in the body.

A paraganglion (pl. paraganglia) is a group of non-neuronal cells derived of the neural crest. They are named for being generally in close proximity to sympathetic ganglia. They are essentially of two types: (1) chromaffin or sympathetic paraganglia made of chromaffin cells and (2) nonchromaffin or parasympathetic paraganglia made of glomus cells. They are neuroendocrine cells, the former with primary endocrine functions and the latter with primary chemoreceptor functions.

ganglion of the sympathetic nervous system

response to emotional pressure suffered for a prolonged period of time in which an individual perceives they have little or no control

Nerve in the cranial cavity

acute stress response in which the individual becomes immobile or paralyzed, often as a way to avoid detection or to assess the threat

Group of nerves in the thorax