Nerve System

Neurons

Basic functional unit of the nervous system that conducts action potentials (nerve impulses).

Neuroglia (glial cells)

Support cells in the nervous system that assist neurons.

Central Nervous System (CNS)

Consists of the brain and spinal cord.

Peripheral Nervous System (PNS)

Includes spinal nerves (31 pairs) and cranial nerves (12 pairs).

Myelin

Lipid wrapping formed by Schwann cells that increases the speed of action potentials along axons.

Synapse

The junction between two neurons where communication occurs.

Bipolar neuron

A neuron with two processes coming off the cell body.

Unipolar neuron

A neuron with one process coming off the cell body.

Multipolar neuron

A neuron with multiple processes coming off the cell body.

Sensory (afferent) neurons

Neurons that carry information to the central nervous system (CNS).

Motor (efferent) neurons

Neurons that carry commands from the central nervous system (CNS).

Meninges

Protective coverings of the brain and spinal cord, consisting of dura mater, arachnoid mater, and pia mater.

Dura mater

The tough outermost layer of the meninges.

Arachnoid mater

The middle web-like layer of the meninges.

Pia mater

The delicate inner layer of the meninges that adheres to CNS structures.

Cerebral cortex

The outer area of gray matter in the brain.

Diencephalon

Part of the brain that includes the thalamus and hypothalamus.

Brainstem

Composed of the midbrain, pons, and medulla.

Cranial nerves I & II

Cranial nerves that arise from the cerebrum; CN I is associated with smell and CN II with sight.

Cauda equina

A mass of nerve roots that passes through the vertebral canal below the end of the spinal cord.

Spinal nerves

Nerves that emerge from the spinal cord, categorized into plexuses.

Action potential

An electrical signal that travels along the neuron.