Language of Medicine Chapter 10

Acetylcholine

A neurotransmitter released at the end of nerve cells that enables learning and memory and also triggers muscle contraction.

Afferent nerve

Carries messages toward the brain and spinal cord (sensory nerve)

Arachnoid membrane

Middle layer of the three membranes (meninges) that surround the brain and spinal cord.

Astrocytes

Type of glial (neuroglial) cell that transports water and salts from capillaries.

Autonomic Nervous System

Nerves that control involuntary body functions of muscles, glands, and internal organs.

Axon

Microscopic fiber that carries the nervous impulse along a nerve cell.

Blood-Brain Barrier (BBB)

Protective separation between blood and brain cells. Makes it difficult for substances to enter the brain.

Brainstem

Posterior portion of the brain that connects the cerebrum with the spinal cord; includes the midbrain, pons, and medulla oblongata.

Cauda Equina

Collection of spinal nerves below the end of the spinal cord.

Cell body

Part of a nerve cell that contains the nucleus.

Central Nervous System (CNS)

The brain and spinal cord.

Cerebellum

Little brain. Posterior part of the brain that coordinates muscle movements and maintains balance.

Cerebral Cortex

Outer region of the cerebrum, containing sheets of nerve cells; gray matter of the brain.

Cerebrospinal Fluid (CSF)

Circulates through the brain and spinal cord.

Cerebrum

Largest part of the brain; responsible for voluntary muscular activity, vision, speech, taste, hearing, thought, and memory.

Cranial nerves

Twelve pairs of nerves that carry messages to and from the brain with regard to the head and neck (except the vagus nerve).

Dendrite

Microscopic branching fiber of a nerve cell that is the first part to receive the nervous impulse.

Dura mater

Thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord

Efferent Nerve

Carries messages away from the brain and spinal cord; motor nerve.

Ependymal Cell

Glial cell that lines membranes within the brain and spinal cord and helps form cerebrospinal fluid.

Ganglion (Plural: ganglia)

Collection of nerve cell bodies in the peripheral nervous system.

Glial cell (neuroglial cell)

Supportive and connective nerve cell that does not carry nervous impulses. (Astrocytes, microglial cells, ependymal cells, and oligodendrocytes. These can reproduce themselves.

Gyrus (Plural: gyri)

Sheet of nerve cells that produces a rounded ridge on the surface of the cerebral cortex; convolution.

Hypothalamus

Portion of the brain beneath the thalamus; controls sleep, appetite, body temperature, and secretions from the pituitary gland.

Medulla oblongata

Part of the brain just above the spinal cord; controls breathing, heartbeat, and the size of blood vessels; nerve fibers cross over here

Meninges

Three protective membranes that surround the brain and spinal cord.

Microglial cell

Phagocytes glial cell that removes waste products from the central nervous system.

Midbrain

Uppermost portion of the brainstem.

Motor Nerve

Carries messages away from the brain and spinal cord to muscles and organs; efferent nerve.

Myelin Sheath

Covering of white fatty tissue that surrounds and insulates the axon of a nerve cell. Speeds impulse conduction along axons.

Nerve

Macroscopic cord-like collection of fibers (axon and dendrites) that carry electrical impulses.

Neuron

Nerve cell that carries impulses throughout the body; parenchyma of the nervous system.

Neurotransmitter

Chemical messenger released at the end of a nerve cell. It stimulates or inhibits another cell, which can be a nerve cell, muscle cell, or gland, (Acetylcholine, norepinephrine, epinephrine, serotonin, dopamine, and endorphins.)

Oligodendroglial cell (Oligodendrocyte)

Glial cell that forms the myelin sheath covering axons.

Parasympathetic Nerves

Involuntary, autonomic nerves that regulate normal body functions such as heart rate, breathing, and muscles of the gastrointestinal tract.

Parenchyma

Essential, distinguishing tissue of any organ or system

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the CNS to the rest of the body

Pia mater

Thin, delicate inner membrane of the meninges

Plexus

Large, interlacing network of nerves

Pons

Part of the brain anterior to the cerebellum and between the medulla and the rest of the midbrain.

Receptor

Organ that receives a nervous stimulus and passes it on to afferent nerves.

Sciatic nerve

Nerve extending from the base of the spine down the thigh, lower leg, and foot. Pain or inflammation along the course of the nerve.

Sensory nerve

Carries messages toward the brain and spinal cord from a receptor; afferent nerve

Spinal nerves

31 pairs of nerves arising from the spinal cord

Stimulus

Agent of change in the internal or external environment that evokes a response

Stroma

Connective tissue and supporting tissue of an organ. Glial cells make up this tissue of the brain.

Sulcus (Sulci)

Depression or groove in the surface of the cerebral cortex; fissure.

Sympathetic nerves

Autonomic nerves that influence bodily functions involuntarily in times of stress

Synapse

Space through which a nervous impulse travels between nerve cells or between nerve muscles of glandular cells.

Thalamus

Main relay of the brain. Conducts impulses between the spinal cord and the cerebrum; incoming sensory messages are relayed through this to appropriate centers in the cerebrum.

Vagus nerve

Tenth cranial nerve; branches reach to the larynx, trachea, bronchi, lungs, aorta, esophagus, and stomach.

Ventricles of the brain

Canals in the brain that contain cerebrospinal fluid.

cerebell/o

cerebellum

cerebr/o

cerebrum

dur/o

dura mater

encephal/o

brain

gli/o

glial cells

lept/o

thin, slender

mening/o

meningi/o

membranes, meninges

my/o

muscle

myel/o

spinal cord

neur/o

nerve

pont/o

pons

radicul/o

nerve root (of spinal nerves)

thalam/o

thalamus

vag/o

vagus nerve (10th cranial nerve)

alges/o

\-algesia

sensitivity to pain

\-algia

pain

caus/o

burning

comat/o

deep sleep (coma)

esthesi/o

\-esthesia

feeling, nervous sensation

kines/o

kinesi/o

\-kinesia

\-kinesis

\-kinetic

movement

\-lepsy

seizure

lex/o

word, phrase

\-paresis

weakness

\-phasia

speech

\-plegia

paralysis (loss or impairment of the ability to move parts of the body)

\-praxia

action

\-sthenia

strength

syncop/o

to cut off, cut short

tax/o

order, coordination

hydrocephalus

abnormal accumulation of fluid (CSF) in the brain

spina bifida

congenital defects in the lumbar spinal column caused by imperfect union of vertebral parts (neural tube defect)

Alzheimer disease (AD)

brain disorder marked by gradual and progressive mental deterioration (dementia), personality changes, and impairment of daily functioning

amyotrophic lateral sclerosis (ALS)

degenerative disorder of motor neurons in the spinal cord and brainstem

epilepsy

chronic brain disorder characterized by recurrent seizure activity.

Tonic-clonic seizures (epilepsy)

characterized by a sudden loss of consciousness, falling down, and then tonic contractions (stiffening of muscles) followed by clonic contractions (twitching and jerking movements of the limbs). Often preceded by an aura (sensation such as dizziness, numbness, or visual disturbances)

absence seizures

form of seizure consisting of momentary clouding of consciousness and loss of awareness of the person’s surroundings.

temporal lobe epilepsy

seizures begin in the temporal lobe of the brain

complex partial seizure

complex means impaired consciousness and partial indicates not generalized. These patients have seizures that cause them to pause in whatever they are doing, become confused, and have memory problems.

Huntington disease (huntington’s)

hereditary disorder marked by degenerative changes in the cerebrum leading to abrupt involuntary movements and mental deterioration

multiple sclerosis (MS)

destruction of the myelin sheath on neurons in the CNS and its replacement by plaques of sclerotic (hard) tissue

Demyelination

loss of myelin insulation; prevents the conduction of nerve impulses through the axon. Causes parethesias, muscle weakness, unsteady gait(walking), and paralysis. May be visual and speech disturbances.

myasthenia gravis (MG)

autoimmune neuromuscular disorder characterized by weakness of voluntary muscles.

palsy

paralysis (partial or complete loss of motor function)

cerebral palsy

partial paralysis and lack of muscular coordination caused by loss of oxygen or blood flow to the cerebrum during pregnancy or in the perinatal period.

bell palsy

paralysis on one side of the face. Likely caused by a viral infection.

Parkinson disease (Parkinson’s)

degeneration of neurons in the basal ganglia, occurring in later life and leading to tremors, weakness of muscles and slowness of movement.

tourette syndrome (tourette’s)

involuntary, spasmodic, twitching movements; uncontrollable vocal sounds; and inappropriate words

herpes zoster (shingles)

viral infection affecting peripheral nerves.