An all-or-none response pattern is characteristic of the

A) activation of either the sympathetic or the parasympathetic system.
B) release of endorphins into the central nervous system.
C) release of hormones into the bloodstream.
D) initiation of neural impulses.

All-Or-None Response

A neuron’s reaction of either firing (with a full-strength response) or not firing.

Neural Impulses

Electrical signals that travel along neurons, transmitting messages throughout the nervous system.

Sympathetic System

Part of the autonomic nervous system that prepares the body for 'fight or flight' responses, increasing heart rate, dilating airways, and mobilizing energy.