From Textbook (Anatomy Vocabulary) - Unit 10: The Nervous System

afferent nerves

Nerves that carry sensory nerve impulses from the body to the spinal cord or brain

autonomic nervous system

Division of the peripheral nervous system that carries nerve impulses to the heart, involuntary smooth muscles, and glands. It includes the parasympathetic division and the sympathetic division.

central nervous system

Division of the nervous system that includes the brain and the spinal cord

efferent nerves

Nerves that carry motor nerve impulses from the spinal cord or brain to the body

nervous system

Body system that consists of the brain, spinal cord, cranial nerves, and spinal nerves. It includes the central nervous system and the peripheral nervous system and its divisions. The nervous system is made of neural tissue.

parasympathetic division

Division of the autonomic nervous system. Its neurotransmitter is acetylcholine. It directs the activity of the heart, involuntary smooth muscles, and glands while the body is at rest.

peripheral nervous system

Division of the nervous system that includes the cranial nerves and the spinal nerves

receptor

Structure on the cell membrane of a dendrite (or on a muscle, organ, or gland) where a neurotransmitter binds

reflex

Rapid, involuntary muscle reaction that is controlled by the spinal cord. In response to sudden pain or muscle stretch, the spinal cord immediately sends a motor command to move. All of this takes place without conscious thought or processing by the brain. The entire circuit that the nerve impulse travels is also known as a reflex arc.

somatic nervous system

Division of the peripheral nervous system that controls the movements of voluntary skeletal muscles

sympathetic division

Division of the autonomic nervous system. Its neurotransmitter is norepinephrine. It directs the activity of the heart, involuntary smooth muscles, and glands during times of increased activity. During danger or stress ("fight or flight"), it stimulates the adrenal gland to release the hormone epinephrine into the blood.

arachnoid

Thin, middle layer of the meninges. Beneath it is a spider-weblike network of fibers that goes into the subarachnoid space and connects the arachnoid to the pia mater layer.

auditory cortex

Area in the temporal lobe of the cerebrum that analyzes sensory information from receptors in the cochlea for the sense of hearing

brain

Largest organ of the nervous system. It is part of the central nervous system and is located in the cranial cavity.

brainstem

Column of tissue that begins in the center of the brain and continues inferiorly to join the spinal cord. The brainstem is composed of the midbrain, pons, and medulla oblongata.

cerebellum

Small, rounded structure that is the most posterior part of the brain. It receives information about muscle tone and body position. It maintains the balance and coordinates muscle movements.

cerebral cortex

The outermost surface of the cerebrum. It consists of gray matter that contains the cell bodies of neurons.

cerebrospinal fluid

Clear fluid that is produced by the ependymal cells that line the ventricles in the brain and the canal within the spinal cord. It circulates through the ventricles, into the spinal cavity, back to the brain, and through the subarachnoid space of the meninges. It cushions and protects the brain and contains glucose and other nutrients.

cerebrum

The largest and most visible part of the brain. Its surface contains gyri and sulci, and it is divided into two hemispheres. It is also divided into lobes.

corpus callosum

Connecting band of neurons between the two hemispheres of the cerebrum that allows them to communicate and coordinate their activities

cranial cavity

Hollow cavity inside the bony cranium that contains the brain

dura mater

Tough, outermost layer of the meninges. The dura mater lies just beneath the bones of the cranium and within the foramen of each vertebra.

fissure

Deep division that runs in an anterior-to-posterior direction through the superior surface of the cerebrum and divides it into right and left hemispheres

frontal lobe

Lobe of the cerebrum that originates conscious thought and intelligence and predicts future events and consequences. Exerts conscious control over the skeletal muscles. Contains the speech center that coordinates muscles for speaking. Contains the gustatory cortex for the sense of taste.

gustatory cortex

Area in the frontal lobe of the cerebrum that analyzes sensory information from taste receptors in the tongue for the sense of taste.

gyrus

One of many elevated folds on the surface of the cerebrum. In between each gyrus is a sulcus (narrow groove).

hemisphere

One half of the cerebrum. The right hemisphere recognizes faces, patterns, three-dimensional structures and the emotions of words. The left hemisphere deals with mathematical and logical reasoning, problem-solving, and recall of memories. It is active in language skills and processing language.

hypothalamus

Area in the center of the brain just below the thalamus that coordinates the activities of the pons and medulla oblongata. It controls the heart rate, blood pressure, respiratory rate, body temperature, and sensations of hunger and thirst. It also produces hormones as part of the endocrine system

lobe

Large area of the cerebrum. Each lobe is named for the bone of the cranium that is above it: frontal lobe, parietal lobe, temporal lobe, and occipital lobe.

medulla oblongata

Most inferior part of the brainstem that joins to the spinal cord. It contains the respiratory centers. The motor portions of cranial nerves IX through XII begin here. The sensory portions of cranial nerves IX and X end here.

meninges

Three separate membranes that envelop and protect the entire brain and spinal cord. The meninges include the dura mater, arachnoid, and pia mater.

midbrain

Most superior part of the brainstem. It keeps the mind conscious, coordinates immediate responses, and maintains muscle tone and body position. It contains the substantia nigra. Cranial nerves III and IV begin here.

occipital lobe

Lobe of the cerebrum that receives and analyzes sensory information from the eyes. Contains the visual cortex for the sense of sight.

olfactory cortex

Area in the temporal lobe of the cerebrum that analyzes sensory information from receptors in the nose for the sense of smell

parietal lobe

Lobe of the cerebrum that receives and analyzes sensory information about touch, temperature, vibration, and pain from the skin, joints, and muscles.

pia mater

Thin, delicate, innermost layer of the meninges. It covers the surface of the brain and contains many small blood vessels.

pons

Middle part of the brainstem that relays nerve impulses from the spinal cord to the midbrain, hypothalamus, thalamus, and cerebrum. The motor portions of cranial nerves V through VII begin here. The sensory portions of cranial nerves V and VII end here.

somatosensory area

Area of the parietal lobe of the cerebrum that analyzes sensory information (touch, temperature, vibration, and pain) from receptors in the skin, joints, and muscles

subarachnoid space

Space beneath the arachnoid layer of the meninges. It is filled with cerebrospinal fluid.

substantia nigra

A gray-to-black pigmented area in the midbrain of the brainstem that produces the neurotransmitter dopamine

sulcus

Groove between two gyri on the surface of the cerebrum

temporal lobe

Lobe of the cerebrum that receives and analyzes sensory information about hearing and smells. It contains the auditory cortex for the sense of hearing and the olfactory cortex for the sense of smell.

thalamus

Area in the center of the cerebrum that is a relay station. It takes sensory information from the cranial and spinal nerves and sends it to the midbrain and the cerebrum.

ventricle

One of four interconnected cavities in the brain that contains cerebrospinal fluid. The two lateral ventricles are in the right and left hemispheres of the cerebrum. The small third ventricle is between the two lobes of the thalamus. The long, narrow fourth ventricle connects to the spinal cavity.

visual cortex

Area in the occipital lobe of the cerebrum that receives and analyzes sensory information from the retina of each eye for the sense of sight

cauda equina

Group of nerve roots that begin where the spinal cord ends and continue inferiorly within the spinal cavity. They look like the tail (cauda) of a horse (equine).

epidural space

Area between the dura mater and the vertebral body. It is filled with fatty tissue and blood vessels.

spinal cavity

Hollow cavity within each vertebra. It contains the spinal cord. It is also known as the spinal canal.

spinal cord

Part of the central nervous system. It begins at the medulla oblongata of the brain and extends down the back within the spinal cavity. It ends at lumbar vertebra L2 where it separates into nerve roots (cauda equina).

abducens nerve

Cranial nerve VI. Motor nerve. Movement of the eye.

accessory nerve

Cranial nerve XI. Motor nerve. Movement of the muscles for swallowing, the vocal cords, and muscles of the neck and upper back. Two of its nerve branches also assist the vagus nerve.

cranial nerves (I–XII)

Twelve pairs of nerves that originate in the brain. They carry sensory nerve impulses to the brain and/or motor nerve impulses from the brain.

facial nerve

Cranial nerve VII. Sensory and motor nerve. Sense of taste for the front of the tongue. Movement of the facial muscles and salivary and lacrimal glands.

glossopharyngeal nerve

Cranial nerve IX. Sensory and motor nerve. Sense of taste for the back of the tongue. Receives information about blood pressure and oxygen/carbon dioxide levels. Movement of the muscles for swallowing and the parotid salivary glands.

hypoglossal nerve

Cranial nerve XII. Motor nerve. Movement of the tongue.

oculomotor nerve

Cranial nerve III. Motor nerve. Movement of the eye, eyelids, and iris (to change the diameter of the pupil).

olfactory nerve

Cranial nerve I. Sensory nerve. Sense of smell.

optic nerve

Cranial nerve II. Sensory nerve. Sense of vision.

trigeminal nerve

Cranial nerve V. Sensory and motor nerve. Sensation in the face and mouth. Movement of the muscles for chewing. It consists of three branches: ophthalmic nerve, maxillary nerve, mandibular nerve.

trochlear nerve

Cranial nerve IV. Motor nerve. Movement of the eye.

vagus nerve

Cranial nerve X. Sensory and motor nerve. Sensation of taste from the soft palate and throat. Sensation in the ears, diaphragm, and the internal organs. It controls the heart rate and the smooth muscles in the bronchi and GI tract.

vestibulocochlear nerve

Cranial nerve VIII. Sensory nerve. Sense of hearing and balance. It is also known as the auditory nerve.

dorsal nerve roots

Group of spinal nerve roots that enter the posterior (dorsal) part of the spinal cord and carry sensory nerve impulses from the body to the spinal cord

spinal nerves

Thirty-one pairs of nerves. Each pair joins the spinal cord in the area between two vertebrae. An individual spinal nerve consists of dorsal nerve roots and ventral nerve roots.

ventral nerve roots

Group of spinal nerve roots that exit from the anterior (ventral) part of the spinal cord and carry motor nerve impulses to the body

axon

Part of the neuron that is a single, elongated extension at the opposite end from the dendrites. It conducts the electrical impulse and releases neurotransmitters into the synapse. Larger axons are covered by an insulating layer of myelin.

cytoplasm

Area in the cell body of a neuron that contains structures that produce a neurotransmitter and energy for the neuron

dendrites

Multiple branches at the beginning of a neuron whose receptors bind with a neurotransmitter and convert it to an electrical impulse

myelin

Fatty, white insulating layer around a larger axon. It increases the speed that an electrical impulse can travel along the axon. An axon with myelin is myelinated. Myelin around larger axons in the brain and spinal cord is produced by oligodendroglia. Myelin around larger axons in the cranial and spinal nerves is produced by the Schwann cells.

nerve

A bundle of individual neurons

neuron

An individual nerve cell. The functional part of the nervous system.

nucleus

Structure in the cell body of a neuron that directs cellular activities

synapse

Space between the axon of one neuron and the dendrites of the next neuron. Space between the axon of a neuron and the cells of a muscle, organ, or gland.

astrocyte

Star-shaped cell that provides structural support for neurons, connects them to capillaries, and forms the blood–brain barrier

ependymal cells

Cells that line the walls of the ventricles, spinal cavity, and the central canal within the spinal cord and produce cerebrospinal fluid

microglia

Cells that move,猛gulf, and destroy pathogens anywhere in the central nervous system

neuroglia

Cells that hold neurons in place and perform specialized tasks. Neuroglia include astrocytes, ependymal cells, microglia, oligodendroglia, and Schwann cells.

oligodendroglia

Cells that form the myelin sheath around larger axons in the brain and spinal cord. These cells have few branching structures.

Schwann cells

Cells that form the myelin sheath around larger axons of the cranial and spinal nerves

acetylcholine

Neurotransmitter of the parasympathetic division. It is also between motor neurons and voluntary skeletal muscles in the somatic nervous system.

dopamine

Neurotransmitter between neurons in the cerebral cortex, hypothalamus, midbrain, and limbic system in the brain. Produced by the substantia nigra of the midbrain

endorphins

Neuromodulators that are one of several natural pain relievers produced by the brain

epinephrine

Neurotransmitter secreted by the adrenal gland and released into the blood. It stimulates the body to prepare for "fight or flight."

neurotransmitter

Chemical messenger that travels across the synapse between neurons

norepinephrine

Neurotransmitter of the sympathetic division. It is also secreted by the adrenal gland.

serotonin

Neurotransmitter between neurons in the limbic system, hypothalamus, cerebellum, and spinal cord