chapter 13 central nervous system

Nerve

A bundle of axons in the peripheral nervous system (PNS) that carries signals between the CNS and the body.

Tract

A bundle of axons within the central nervous system (CNS).

Ganglia

Clusters of neuron cell bodies in the PNS.

White matter

Regions of the CNS that contain myelinated axons.

Gray matter

Regions of the CNS that contain neuron cell bodies, dendrites, and unmyelinated axons.

Cerebrum

The largest part of the brain, consisting of two hemispheres connected by the corpus callosum.

Diencephalon

A region of the brain that includes structures such as the thalamus, hypothalamus, and epithalamus.

Brainstem

The part of the brain that controls automatic survival functions like breathing and heart rate.

Cerebellum

The part of the brain responsible for coordinating balance and voluntary movement.

Cerebral cortex

The thin outer layer of gray matter responsible for higher brain functions such as thinking and voluntary movement.

Longitudinal fissure

A deep groove that separates the right and left cerebral hemispheres.

Corpus callosum

A thick band of white matter that connects the two cerebral hemispheres.

Sulcus (sulci)

A shallow groove on the surface of the brain.

Gyrus (gyri)

A raised ridge or fold between sulci.

Basal nuclei

Deep clusters of gray matter within the cerebrum that help regulate voluntary motor activities.

Frontal lobe

The brain lobe responsible for voluntary movement, reasoning, and speech production, located deep to the frontal bone.

Parietal lobe

The brain lobe responsible for processing sensory input such as touch and pressure, located posterior to the frontal lobe.

Temporal lobe

The brain lobe involved in hearing, memory, and smell, located inferior to the lateral sulcus.

Occipital lobe

The brain lobe responsible for vision and visual processing, located at the posterior part of the brain.

Insula

A brain region deep within the lateral sulcus responsible for taste, visceral sensations, and emotion.

Central sulcus

A groove that separates the frontal lobe from the parietal lobe, dividing motor and sensory areas.

Broca's area

A region located in the left frontal lobe that controls speech production; damage here can lead to Broca’s aphasia.

Thalamus

An egg-shaped mass of gray matter that acts as a relay station for sensory information going to the cerebral cortex.

Hypothalamus

A structure located below the thalamus that regulates homeostasis, hunger, thirst, and connects to the pituitary gland.

Epithalamus

A part of the diencephalon that includes the pineal gland, which secretes melatonin to regulate sleep.

Pons

A structure that connects the cerebrum to the cerebellum.

Medulla oblongata

The brain structure that controls vital functions such as heart rate and blood pressure; it contains reflex centers.

Cerebellum

Located posterior to the pons and medulla, it coordinates balance, posture, and smooth movements.

Spinal cord

Transmits sensory and motor impulses between the body and brain and acts as a reflex center.

Cauda equina

A bundle of spinal nerve roots that resembles a horse’s tail, extending from the lower spinal cord.

Pia mater

The innermost layer of protective covering directly covering the brain and spinal cord.

Arachnoid mater

The middle layer of protective covering with a web-like appearance.

Dura mater

The outermost tough layer of protective covering that provides protection and support.

Choroid plexuses

Capillary networks that produce cerebrospinal fluid (CSF) within the ventricles.

Cerebrospinal fluid (CSF)

A clear fluid that cushions the brain and spinal cord and maintains chemical stability.

Ventricles

Fluid-filled cavities in the brain that are filled with cerebrospinal fluid (CSF) and lined with ependymal cells.

Arachnoid villi

Structures that absorb cerebrospinal fluid (CSF) into the venous blood.