The cells that provide structural, nutritional, and other functions for neurons.

The branching fibers of neurons that receive neural impulses from other neurons and convey impulses toward the cell body.

The part of a neuron that contains the cell nucleus and other structures that help the neuron carry out its functions.

A long, tube-like structure that conveys impulses away from a neuron's cell body toward other neurons or to muscles or glands.

The layer of fatty insulation wrapped around the axons of some neurons that increases the rate at which neural impulses travel along the axon.

A neural impulse, or brief electrical charge, that carries information along the axon of a neuron; movement is generated when positively charged ions move in and out through channels in the axon's membrane.

The principle that a neuron's response to a stimulus is either to fire with full-strength response or not to fire at all.

The gap between the axon tip of the sending neuron and the dendrite and/or cell body of the receiving neuron.

A chemical messenger released by neurons that travel across the synapse and allows neurons to communicate with one another.

A molecule that binds to a receptor and triggers a response that mimics or enhances a neurotransmitter's effect.

A molecule that binds to a receptor and triggers a response that blocks a neurotransmitter's effect.

A chemical substance in the nervous system similar in structure and action to opiates; involved in pain control, pleasure, and memory.

A network of glands located throughout the body that manufacture and secrete hormones and secrete hormones into the bloodstream.

Chemical messengers manufactured and secreted by the endocrine glands, which circulate in the bloodstream to produce bodily changes or maintain normal bodily functions.