Ch. 8 Structure and Function

acetylcholine

Chemical that stimulates cells.

afferent (sensory) neuron

Neuron that carries information from the sensory receptors to the central nervous system.

arachnoid

Middle layer of meninges.

astrocyte (astroglia)

A type of neuroglia that maintains nutrient and chemical levels in neurons.

autonomic nervous system

Part of the peripheral nervous system that carries impulses from the central nervous system to glands, smooth muscles, cardiac muscle, and various membranes.

axon

Part of a nerve cell that conducts nerve impulses away from the cell body.

basal ganglia

Large masses of gray matter within the cerebrum.

brain

Body organ responsible for controlling the body's functions and interactions with outside stimuli.

brainstem

One of the four major divisions of the brain; division that controls certain heart, lung, and visual functions.

cell body

Part of a nerve cell that has branches or fibers that reach out to send or receive impulses.

central nervous system

The brain and spinal cord.

cerebellum

One of the four major divisions of the brain; division that coordinates musculoskeletal movement.

cerebral cortex

Outer portion of the cerebrum.

cerebrospinal fluid (CSF)

Watery fluid that flows throughout the brain and around the spinal cord.

cerebrum

One of the four major divisions of the brain; involved with emotions, memory, conscious thought, moral behavior, sensory interpretation, and certain bodily movements.

conductivity

Ability to transmit a signal.

convolutions

Folds in the cerebral cortex; gyri.

corpus callosum

Bridge of nerve fibers that connects the two hemispheres of the cerebrum.

cranial nerves

Any of 12 pairs of nerves that carry impulses to and from the brain.

cranium

Bony structure that the brain sits in.

dendrite

A thin branching extension of a nerve cell that conducts nerve impulses toward the cell body.

diencephalon

One of the four major structures of the brain; deep portion of the brain that contains the thalamus.

dura mater

Outermost layer of meninges.

efferent (motor) neuron

Neuron that carries information to the muscles and glands from the central nervous system.

epidural space

Area between the pia mater and the bones of the spinal cord.

epithalamus

One of the parts of the diencephalon; serves as a sensory relay station. [most posterior (back) and dorsal (top) part of the diencephalon]

excitability

Ability to respond to stimuli.

fissure

One of many indentations of the cerebrum; sulcus.

frontal lobe

One of the four parts of each hemisphere of the cerebrum.

gyrus

See convolution.

hypothalamus

One of the parts of the diencephalon; serves as a sensory relay station.

interneuron

Neuron that carries and processes sensory information.

medulla oblongata

Part of the brainstem that regulates heart and lung functions, swallowing, vomiting, coughing, and sneezing.

meninges

Three layers of membranes that cover and protect the brain and spinal cord.

microglia

A type of neuroglia that removes debris.

midbrain

Part of the brainstem involved with visual reflexes.

myelin sheath

Fatty tissue that covers axons.

nerve

Bundle of neurons that carry electrical messages to the organs and muscles of the body.

nerve cell

Basic cell of the nervous system having three parts; cell body, dendrite, and axon; also called a neuron.

nerve impulse

Released energy that is received or transmitted by tissue or organs and usually provokes a response.

neurilemma

Membranous covering that protects the myelin sheath.

neuroglia

Cell of the nervous system that does not transmit impulses.

neuron

Basic cell of the nervous system having three parts; also called a nerve cell.

neurotransmitters

Various substances located in tiny sacs at the end of the axon.

occipital lobe

One of the four parts of each hemisphere of the cerebrum.

oligodendroglia

A type of neuroglia that produces myelin and helps support neurons.

parasympathetic nervous system

Part of the autonomic nervous system that operates when the body is in a normal state.

parietal lobe

One of the four parts of each hemisphere of the cerebrum.

pia mater

Innermost layer of meninges.

pons

Part of the brainstem that controls certain respiratory functions.

receptor

Tissue or organ that receives nerve impulses.

somatic nervous system

Part of the peripheral nervous system that receives and processes sensory input from various parts of the body.

spinal cord

Ropelike tissue that sits inside the vertebral column and from which spinal nerves extend.

spinal nerves

Any of 31 pairs of nerves that carry messages to and from the spinal cord and the torso and extremities.

stimulus

Anything that arouses a response.

subdural space

Area between the dura mater and the pia mater across which the arachnoid runs.

sulcus

See fissure.

sympathetic nervous system

Part of the autonomic nervous system that operates when the body is under stress.

synapse

Space over which nerve impulses jump from one neuron to another.

temporal lobe

One of the four parts of each hemisphere of the cerebrum.

terminal end fibers

Group of fibers at the end of an axon that passes impulses to the next neuron.

thalamus

One of the four parts of the diencephalon; serves as a sensory relay station.

ventral thalamus

One of the four parts of the diencephalon; serves as a sensory relay station.

ventricle

Cavity in the brain for cerebrospinal fluid.