Chapter 15

ganglion

1. A knot, or knotlike mass. 2. One of the nerve cell bodies located outside the central nervous system. 3. A benign cystic tumor on a tendon or aponeurosis, consisting of a fibrous capsule filled with a clear mucinous fluid.

unconsciousness

1. An inability to respond to the surrounding environment. 2. In psychology, the part of the mind that is not readily accessible but may be manifested in dreams or when a person is under the influence of drugs.

pons

1. Any bridge of tissue connecting two parts of an organ. 2. The portion of the central nervous system situated between the mesencephalon and the medulla oblongata, superior to the cerebellum.

efferent

1. Conducted away from a center. Also called centrifugal. 2. Something that so conducts.

dendrite

1. One of the threadlike extensions of the cytoplasm of a neuron, which usually branch into treelike processes. 2. A dendritic ulcer.

sensory

1. Pertaining to sensation. 2. Pertaining to all or a portion of the body's sensory nerve network.

frontal lobe

1. Pertaining to the forehead. 2. Denoting a longitudinal plane of the body at right angles to the sagittal plane.

occipital lobe

1. Pertaining to the occiput, the posterior portion of the head 2. Situated near the occipital bone. 3. The occipital lobe of the brain. It is within this lobe that visual images are registered. The occipital lobe also contains the visual associative areas, which enable interpretation of images.

temporal lobe

1. Pertaining to the temporal bone of the skull. 2. Pertaining to time; limited by time; temporary. found in the lateral region of the cerebrum. this lobe is involved with the functions of hearing, taste, smell, and balance.

spinal nerves

31 pairs. transmit information to and from the central nervous system. attached to the spinal cord they communicate with the abdomen, chest, and extremities making sensation and movement possible

hydrocephalus

A congenital or acquired condition characterized by dilation of the cerebral ventricles accompanied by an accumulation of cerebrospinal fluid within the skull. Also called hydrocephaly.

myelin sheath

A cylindrical structure, composed largely of phospholipids and protein, that covers the axons of some nerves in the body.

meningomyelocele

A developmental anomaly of the central nervous system in which a hernial sac containing a part of spinal cord, its meninges, and cerebrospinal fluid protrudes through a congenital defect in the vertebral arch (spina bifida). Also called myelomeningocele.

Neurologist

A physician who focuses on neurology.

multiple sclerosis (MS)

A slowly progressing degenerative disease characterized by demyelination of the nerve fibers of the brain and spinal cord.

ventricle

A small cavity, such as the left and right ventricles of the heart or one of the cerebrospinal fluid-filled cavities in the brain. Also called ventriculus. any fluid filled brain cavity.

coma

A state of unconsciousness from which the patient cannot be aroused; characterized by the absence of vocalization, spontaneous eye openings, and response to powerful stimuli.

concussion

A violent jar or shock or the condition that results from such an injury.

herpes zoster

Acute, painful, infectious rash caused by reactivation of the latent varicella zoster virus, which mainly affects adults. Also known as shingles.

glial cells (glia or neuroglia)

Also called neuroglia; connective, supportive tissue cells within the nervous system that do not carry impulses. Supporting or connective tissue cells of the central nervous system.

hyperesthesia

An abnormal condition of increased sensitivity, particularly a painful reaction to normally painless touch stimuli.

vagus

Designating the tenth cranial nerve.

vagus nerve

Either of the pair of cranial nerves primarily responsible for parasympathetic control over the heart and several other internal organs.

cerebrospinal fluid (CSF)

Fluid that flows through and protects the four ventricles of the brain, the spinal canal, and the subarachnoic spaces. CSF consists primarily of secretions of the choroid plexi in the lateral ventricles and in the third and fourth ventricles of the brain. helps to further cushion the vital nervous system structures

cephalalgia

Headache. Also called cephalgia and cephalodynia.

midbrain

Informal for mesencephalon, one of the three parts of the brainstem, situated below the cerebrum and above the pons.

afferent

Moving toward a center, as applied to nerves, vessels, veins, and lymphatics.

thalamus

One of a pair of large ovoid structures situated in the posterior area of the diencephalon and forming most of the lateral walls of the third ventricle of the brain. It is divided into anterior, medial, and lateral parts, each containing nuclei that serve as relay centers for sensory impulses.

glioma

Originally, a tumor made up of tissue representing neuroglia in any stage of its development; use of the term has been extended to encompass all the primary malignant tumors of the brain and spinal cord, including astrocytomas, endymomas, medulloblastomas, and others. Also called neuroglioma, neurogliocytoma, and neurospongioma.

neuralgia

Pain extending along one or more nerves.

cranial nerves

Pertaining to the cranium. there are 12 pairs of nerves

parietal lobe

Pertaining to the outer wall of a cavity or organ. areas of the parietal lobe serve as centers for language and general sensory functions

arachnoid

Resembling a spiderweb, as the arachnoid membrane.

meningocele

Saclike hernial protrusion of the meninges through a bony defect in the skull or vertebral column.

-itis

Suffix denoting inflammation.

brain

That portion of the central nervous system contained within the cranium, consisting of the cerebrum, pons, cerebellum, medulla, and midbrain. Functions include memory storage, speech production, muscle control and coordination, and sensory reception and integration.

central nervous system (CNS)

The division of the nervous system that consists of the spinal cord and brain; serves to process information to and from the peripheral nervous system and acts as the primary network of control and coordination for the entire body.

axon

The extension of a neuron by which impulses travel away from the cell body; capable of conduction action potentials.

gray matter

The inner section, or core, of the cord. so-called because the cell bodies and dendrites of what are, predominantly, interneurons and motor neurons, are unmyelinated and, thus, gray in color. White matter—a large bundle of myelinated

spinal cord

The long cylindric part of the central nervous system that is lodged in the vertebral canal, continuous with the medulla oblongata and extending from the foramen magnum to the upper part of the lumbar region. It is composed of an inner core of gray matter, in which nerve cells predominate, and an outer white layer of myelinated nerve fibers, and is enclosed by three protective meninges: the dura mater, arachnoid, and pia mater. The cord conducts motor and sensory impulses to and from the brain and regulates many autonomic reflexes.

cerebrum

The main portion of the brain, occupying the upper section of the cranial cavity. Its two hemispheres are connected by the corpus callosum and form the largest part of the central nervous system.

glioblastoma multiforme

The most malignant form of astrocytoma.

dura mater

The outermost, toughest, and most fibrous of the three membranes surrounding the brain and spinal cord.

synapse

The point of functional contact between neurons or between a neuron and an effector organ, across which nerve impulses are transmitted, usually by a chemical neurotransmitter released by the axon terminal of the stimulated cell.

diencephalon

The portion of the brain between the mesencephalon and the cerebrum, consisting of the thalamus, hypothalamus, and epithalamus and including most of the third ventricle.

cerebellum

The portion of the metencephalon that is located in the posterior cranial fossa, behind the brainstem, and plays a role in the coordination of movements.

peripheral nervous system (PNS)

The sensory and motor nerves and ganglia outside the brain and spinal cord, comprising 31 pairs of spinal nerves, 12 pairs of cranial nerves, and their branches in body organs.

brainstem

The stalklike part of the brain comprising the medulla oblongata, pons, and mesencephalon; connects the cerebral hemispheres with the spinal cord. Also written brain stem.

meninges

The three membranes enveloping the spinal cord and brain, namely, the pia mater, the dura mater, and the arachnoid.

medulla

The truncated cone of nervous tissue continuous above with the pons and below with the spinal cord; contains the cardiac, vasomotor, and respiratory centers of the brain.

hypothalamus

The ventral portion of the diencephalon, forming the floor and part of the lateral wall of the third ventricle. It activates, integrates, and controls the endocrine processes, somatic functions, and peripheral autonomic nervous system.

nerve tracts

This large bundle of nerve fibers is divided into smaller bundles

blunt trauma

`The brain may be injured at the site of its impact against the cranial wall as well as from rebounding against the opposite skull surface. Swelling of brain tissue and damage to the brain's vasculature can cause bleeding and the accumulation of blood within the cranium. An injury of this kind may result in persistent neurologic problems.

reye syndrome

a condition that may follow acute viral infection and is characterized by acute encephalopathy combined with fatty infiltration of internal organs.

white matter

a large bundle of myelinated axons—surrounds the core of the spinal cord.

spinal cord

a long, cylindrical structure that extends from the medulla oblongata to the upper part of the lumbar region, just above the pelvis. In the average adult, the spinal cord measures about 18 inches in length.

neuroma

a tumor composed of nerve cells and fibers

encephalopathy

any abnormal condition affecting the structure of function of brain tissues

impulse conduction

begins when the receptors of our sensory neurons detect a change in the environment

coup

blow to the body

combining form for cerebellum

cerebell/o

combining form for cerebrum

cerebr/o

head injury

describes any traumatic damage to the scalp, skull, or brain tissues. the damage may range from a minor wound to penetration of the skull with severe injury to brain structures

mononeuropathy

disease that affects a single nerve

combining form for dura mater

dur/o

combining form for brain

encephala/o

Combining form denoting relationship to feeling or perception.

esthesi/o

combining form for ganglion

gangli/o, ganglion/o

gli/o

gluey substance

-cele

hernia

neuritis

inflammation of a nerve

polyneuritits

inflammation of many nerves

encephalitis

inflammation of the brain

cerebellitis

inflammation of the cerebellum

duritis

inflammation of the dura mater

radiculitis

inflammation of the nerve root

neuropathy

is a general term that describes any disorder of a nerve, usually referring to a peripheral nerve

sulcus

is a shallow depression on the surface of an organ. is usually not as deep as a fissure, but the two terms are often used interchangeably in the context of anatomy

shingles

is an infectious disorder that affects the peripheral nerves. An acute infection caused by activation of latent human herpesvirus 3 and characterized by severe neuralgic pain along the course of the affected nerves and clusters of vesicular skin eruptions on the corresponding area of skin. Also called herpes zoster.

meningitis

is an inflammatory condition that affects the brain and spinal cord. infecting agents, fir example, bacteria, viruses, and fungi- enter the central nervous system through the bloodstream or as a consequence of an upper respiratory infection, causing acute inflammation of the pia mater and arachnoid membrane.

polyneuropathy

is inflammation or degeneration of several peripheral nerves

combining form for medulla oblongata

medull/o

combining form for meninges

mening/o, meningi/o

mening/o

meninges

impulse

moves like a wave along the length of the cell, from dendrite to the axon.

combining form for spinal cord

myel/o

neuron

nerve cell. Any of the basic conducting cells of the nervous system, classified according to the number of processes they extend or according to the direction in which they conduct impulses.

combining form for nerve

neur/o

nervous system structures are formed from two type of cells

neurons and connective tissue cells

combining form for pons

pont/o

combining form for nerve root

radicul/o, radic/o, rhiz/o

peripheral neuropathy

refers in general to a number of disorders of the peripheral nervous system

-esthesia

sensory perceptions or sensations

myel/o

spinal cord

combining form for thalamus

thalam/o

pia mater

the delicate, inner layer, which has a rich supply of blood vessels that nourish the nervous tissue.

sciatica

the inflammation of a specific nerve- the sciatic nerve- including pain and tenderness along the path of the nerve through the thigh and leg. may also be caused by trauma to, or compression of, the nerve or its roots and may result in muscle wasting of the lower leg.

combining form for ventricle

ventricul/o

vertebral canal

which runs through the protective spinal column. The canal also contains the three meningeal coverings of the spinal cord: the cerebrospinal fluid, a cushion of fatty tissue, and blood vessels.