Nervous system

Cerebral hemispheres

The two halves of the brain that are responsible for higher cognitive functions.

Diencephalon

The region of the brain that includes the thalamus, hypothalamus, and epithalamus.

Brain stem

The region of the brain that consists of the midbrain, pons, and medulla, and controls automatic behaviors and voluntary movement.

Cerebellum

The region of the brain that is responsible for coordination and balance.

Gray matter

The part of the brain that contains short, nonmyelinated neurons and cell bodies.

White matter

The part of the brain that contains myelinated and nonmyelinated axons.

Ventricles

Fluid-filled chambers in the brain that are continuous with each other and filled with cerebrospinal fluid.

Gyri

Ridges on the surface of the brain.

Sulci

Shallow grooves on the surface of the brain.

Fissures

Deep grooves on the surface of the brain.

Basal nuclei

Gray matter structures deep within the white matter of the cerebral hemispheres that influence muscle movements and play a role in cognition and emotion.

Thalamus

The egg-shaped nuclei in the diencephalon that act as a relay station for information coming into the cortex.

Hypothalamus

The region below the thalamus that controls the autonomic nervous system and regulates functions like blood pressure and body temperature.

Epithalamus

The most dorsal portion of the diencephalon that contains the pineal gland and secretes melatonin.

Midbrain

The part of the brain stem that contains nuclei involved in pain suppression and the fight-or-flight response.

Pons

The part of the brain stem that relays impulses between the motor cortex and cerebellum.

Medulla oblongata

The part of the brain stem that controls automatic behaviors necessary for survival.

Meninges

The protective layers of connective tissue that surround the CNS, including the dura mater, arachnoid, and pia mater.

Spinal cord

The part of the CNS that extends from the brain stem and is responsible for transmitting signals between the brain and the rest of the body.

Myelin sheath

The protective covering around axons formed by glial cells.

Endoneurium

The connective tissue that wraps individual axons in a nerve.

Perineurium

The connective tissue that wraps axon bundles in a nerve.

Epineurium

The connective tissue that wraps nerves formed by axon bundles.

Cauda equina

The bundle of nerves that extends from the end of the spinal cord and resembles a horse's tail.