Nervous System · definition
A common term for rapid physiological changes that prepare the body for action in response to threat or demand.
How the term is used
The response is strongly associated with sympathetic nervous-system activation and changes in heart rate, breathing, blood flow, and energy availability.
Why it matters
It helps readers understand a normal protective response without labeling all activation as pathology.
Where this comes up
Where this fits in a practice
The guides explain the idea in context; the service pathways are there when reading is not enough. Educational content only — nothing here is medical or mental-health care.