acetylcholine

Neurotransmitter chemical released at the ends of nerve cells.

acetylcholine

Neurotransmitter chemical released at the ends of nerve cells.

afferent nerve

Carries messages toward the brain and spinal cord (sensory nerve).

Afferent comes from af- (a form of ad-, meaning toward) and -ferent (meaning carrying).

arachnoid membrane

The middle layer of the three membranes (meninges) that surround the brain and spinal cord. The Greek Arachne means spider.

astrocyte

Type of glial (neuroglial) cell that transports water and salts from capillaries.

autonomic nervous system

Nerves that control involuntary body functions of muscles, glands, and internal organs.

axon

Microscopic fiber that carries the nervous impulse along a nerve cell.

blood-brain barrier

Protective separation between the blood and brain cells. This makes it difficult for substances (such as anticancer drugs) to penetrate capillary walls and enter the brain.

brainstem

Posterior portion of the brain that connects the cerebrum with the spinal cord; includes the pons and medulla oblongata.

cauda equina

Collection of spinal nerves below the end of the spinal cord.

cell body

Part of a nerve cell that contains the nucleus.

central nervous system

(CNS)

The brain and the spinal cord.

cerebellum

Posterior part of the brain coordinates muscle movements and maintains balance.

cerebral cortex

Outer region of the cerebrum, containing sheets of nerve cells; gray matter of the brain.

cerebrospinal fluid (CSF)

Circulates throughout the brain and spinal cord.

cerebrum

Largest part of the brain; responsible for voluntary muscular activity, vision, speech, taste, hearing, thought, and memory.

cranial nerves

Twelve pairs of nerves that carry messages to and from the brain with regard to the head and neck (except the vagus nerve).

dendrite

Microscopic branching fiber of a nerve cell that is the first part to receive the nervous impulse.

dura mater

Thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord. Latin for “hard mother.”

efferent nerve

Carries messages away from the brain and spinal cord; motor nerve.

Efferent comes from ef- (meaning away from) and -ferent (meaning to carry).

ependymal cell

Glial cell that lines membranes within the brain and spinal cord and helps form cerebrospinal fluid.