Chapter 9 Medical Terms

afferent nerves

Nerves that *only* conduct messages from the sensory receptors to the central nervous system

Alzheimer’s disease (AD)

a form of dementia (progressive mental deterioation) resulting from the atrophy of the frontal and occipital lobes of the brain

amyotrophic lateral sclerosis (ALS)

a disease marked by muscular weakness and atrophy with onvoluntary contractions and excessive reflexes; caused by the degeneration of motor neurons in the spinal cord and in the brain’s medulla and cortex

analgesic

a drug that relieves pain; includes nondescription pain relievers, such as asprin, and prescription pain relievers, such as hydrocodone

anesthetic

a drug that causes a reversible loss of sensation or pain; used to temporarily deaden pain

antianxiety agent

a medication used to reduce feelings of anxiety

anticonvulsant

a drug that prevents or relieves convulsions

antidepressant

a medication used to treat depression

anxiety disorders

a group of mental disorders that share the core characteristic of anxiety (excessive worry, nervousness, or uneasiness)

anxiolytic

an antianxiety drug

arachnoid matter

the middle layer of the meninges, which consists of many thin fibers that connect it to the pia mater

ascending spinal tracts

transmit sensory imformation from organs and glands to the brain

astrocytoma

a tumor of the neuroglial tissue

attention-deficit/hyperactivity disorder (ADHD)

a chronic mental disorder in which a person is frequently distracted, is hyperactive, and displays a lack of impulse control

aura

a subjective sensation that often occus before a migrane or seizure

autism spectrum disorder

a development disability characterized by difficulty communicating with others and focusing beyond oneself; inability to maintain eye contact; motor activity that is repetitious; and a preocupation with small objects

autonomic nervous system (ANS)

the division of the nervous system that controls the involuntary bodily functions; can be divided into the sympathetic and parasympathetic nervous systems

axon

a long, tail-like projection on a neuron, which takes information from the cell body out to the muscles

axon terminals

an offshoot of the axon that branches out to connect with individual muscle fibers

Babinski sign

a reflec in which the toes curl upward when the plantar surface (sole) of the foot is stimulated; also known as the *Babinski reflex*

Bell’s palsy

a condition characterized by a unilateral (one-sided) paralysis of the nerves that control the facial muscles, causing one side of the face to droop

bipolar disorder

a mental disorder characterized by alternating periods of mania (emotional ‘highs’) and depression (emotional ‘lows’)

brain

the organ of the body contained in the cranium, which controls functions, movements, sensations, and thoughts

brain stem

a structure that is located beneath the diencephalon, connects the cerebrum with the spinal cord, and helps regulate the central nervous system by serving as a conduit for sensory information carried between the cerebrum and cerebellum and the rest of the body

brain tumor

any intercranial mass, which may be neoplastic (a new growth), cystic (a sac containing fluid), or inflammatory (an abscess)

bulimia nervosa

an eating characterized by binge eating that is followed by induced vomiting, use of laxatives, and/or excessive exercise; often abbreviated to *bulimia*

carotid endarterectomy

the surgical removal of fatty deposits in one or both carotid arteries (arteries that supply blood to the brain); commonly used to prevent a CVA

cell body

the main part of the cell, which contains the nucleus

central nervous system (CNS)

the collective term for the brain and the spinal cord

cerebellum

the second largest region of the brain, which controls your body’s sense of balance and equillibrium and coordinates movements of voluntary muscles

cerebral aneurysm

an abnormal, localized (limited to one area) dilation of a blood vessel in the cerebrum

cerebral angiography

an X-ray of the blood vessels in the brain after a contrast medium (dye) has been injected; used to diagnose a CVA and other injuries and disorders of the brain

cerebral contusion

a bruising in the cerebral tissue

cerebral cortex

the outer layer of the cerebrum, which contains many folds of curved and depressed areas

cerebral palsy (CP)

a disorder that affects movement and muscle tone; caused by a defect in, or trauma to, the brain before birth

cerebrospinal fluid (CSF)

a clear, watery fluid that envelops and protects the brain and spinal cord

cerebrospinal fluid shunt

a surgically implanted device that drains cerebrospinal fluid in a controlled manner from the brain ventricles to the abdomen or heart; commonly used to treat hydrocephalus

cerebovascular accident (CVA)

the death of brain tissue that occurs when an arterial blockage or arterial rupture prevents blood flow to the brain; commonly called a *stroke*

cerebrum

the largest brain region, which is the seat of high-level cognitive functions such as language, reasoning, planning, memory, and sensory integration

cognitive behavioral therapy (CBT)

a form of psychotherapy or mental health counseling wherin the goal is to help the client to gain an improved awareness of negative thought processes and to adopt strategies for counteracting negative thinking

coma

a state of extended unconsciousness caused by a medical crisis, such as a traumatic brain injury (TBI), stroke, infection, or illness (diabetes, for example)

concussion

a traumatic brain injury (TBI) resulting from a blow to the head or violent shaking of the head and upper body; causes partial or complete loss of brain functions, which can result in memory loss, impaired coordination, balance defecit, and dizziness

convulsion

a sudden, abnormal, involuntary contraction (or series of contractions) of the muscles

corpus callosum

a bundle of nerve tissue that connects the two hemispheres of the brain

craniectomy

the surgical removal of part of the skull to gain access to the brain; most commonly used to treat swelling in the brain

craniotomy

an incision into the skull to gain access to the brain

cytoplasm

a jelly-like substance that makes up most of the cell body and which protects the nucleus

deep tendon reflexes (DTRs)

involuntary muscle contractions that occie when the tendons associated with certain areas of the limbs (for example, the patella, or knee) are percussed with a reflex hammer. DTRs are tested during the neurological exam

delirium

a state of mental confusion and agitation characterized by disorientation of time and place, usually accompanied by hallucinations (false sensory experiences that are percieved as real) and illusions (misperceptions of environmental stimuli)

dementia

a condition of progressive mental disorientation caused by organic brain disease (that is, caused by tissue changes in the brain), which is characterized by memory loss, difficulties with language expression, and inability to perform ordinary daily activities of living

dendrites

branches of a neuron that collect stimuli and transport them to the cell body

depression

a mood disorder marked by persistent feelings of sadness, worthlessness, and lack of interest in daily activities

descending spinal tracts

relay motor commands from the brain to one or more of the peripheral nerves

development disorders

a group of mental disorders characterized by disruption of normal development during childhood

diencephalon

an area of the brain that includes the thalamus, hypothalamus, and pineal gland; also known as the interbrain

diskectomy

the surgical removal of a herniated (protruding) vertebral disk

dura mater

a thick sac of dense collagen fibers and blood vessels; the outermost layer of the meninges

dyslexia\`

a learning disorder characterized by difficulty in recognizing and comprehending written language; affects reading and spelling abilities as well as self-expression

eating disorders

a group of mental disorders characterized by an unhealthy weight and food

effectors

muscles or glands in the body that generate a response in the form of motor output

efferent nerves

nerves that conduct messages from the central nervous system to the muscles or glands of the body

electroconclusive therapy (ECT)

electric shock applied to the brain under medical supervision to trigger convulsions

electorcephalogram (EEG)

a record of the electrical impulses of the brain; used to diagnose neurological conditions that affect brain function and level of consciousness

electroneurodiagnostic (END) technologist

a healthcare worker who uses specialized diagnostic equipment to monitor a patient’s nervous system

epidural hematoma (EDH)

a mass of blood that forms between the skull and the dura mater as a result of the brain colliding against the skull, such as from a head injury or a fall

epilepsy

a neurological disorder of the central nervous system disorder in which the activity of the neural cells in the brain becomes disrupted, causing seizures, unusual sensations, repeated twitching of the limbs, and, occasionally, loss of consciousness

focal seizure

abnormal electrical activity that occurs in one or more parts of one brain hemisphere; also knows as a *partial seizure*

frontal lobes

lobes of the brain located in the anterior part of the cerebrum, which control movement, reasoning, planning, problem solving, speech, and emotions

generalized anxiety disorder (fa con)

an anxiety disorder characterized by excessive worry that is not restricted to specific sitiuations or objects; often associated with physical symptoms such as heart palpitations, chest pain, tremors, sweating, nausea, or headaches

grand mal seizure

an epileptic seizure characterized by violent muscle contractions and loss of consciousness; also known as a *tonic-clonic seizure*

gray matter

unmyelinated nerve tissue that is composed mostly of nerve cell bodies and dendrites

Guillain-Barré syndrome (GB syndrome)

polyneuritis (inflammation of multiple peripheral nerves) characterized by progressive muscle weakness of the extremities, which may lead to paralysis; usually occurs during or after recovery from an infectious disease

gyri

convolutions in the brain

headache

pain that is spread out in one or more parts of the head; unconfined to a particular area of nerve distribution

hemiparesis

paralysis of one side of the body; also known as *hemiplegia*

hemiplegia

paralysis of one side of the body; also known as *hemiparesis*

hemorrhagic stroke

a type of cerebrovascular accident (CVA) that occurs when a weakened blood vessel , such as an aneurysm, ruptures and bleeds into the surrounding tissue of the brain

hydrocephalus

an accumulation of excess cerebrospinal fluid inside the ventricles of the brain, which causes cephalomegaly (enlargement of the head) and which may cause brain damage; commonly seen in young children

hypnotic

a drug that causes sleep or loss of consciousness

hypothalamus

a portion of the diencephalon, which regulates functions such as metabolism, heart rate, and blood pressure

integration

a process during which the central nervous system processes and interprets the information recieved through the sensory organs

intellectual disability (ID)

a condition of below-average intelligence resulting in the inability to develop skills necessary for daily living; also known as *intellectual development disorder* *(IDD)*

involuntary movement

movement that is out of a person’s control

ischemic stroke

a type of cerebrovascular accident (CVA) that occurs when a blood vessel that supplies blood to the brain becomes occluded (blocked)

laminectomy

a procedure in whcih the vertebral lamina, or the part of the bone that makes up a vertebra in the spine, is surgically removed, allowing access to the spinal cord; commonly used to treat a herniated disk

light therapy

the use of a specialized light source, which replicates natural sunlight, to treat seasonal affective disorder

lumbar puncture (LP)

the insertion of a needle between two lumbar vertebrae (in the lower spine) to remove a sample of cerebrospinal fluid for diagnostic evaluation or theraputic treatment; commonly used to diagnose meningitis; also known as *spinal tap*

medulla oblongata

one part of the brain stem, which helps conduct neural impulses from the brain to the spinal cord; regulate breathing, heart rate, blood pressure, and body temperature

meninges

three layers of connective tissue that protect the brain and spinal cord

meningocele

congenital hernia in which the meninges protrude through an opening of the skull or spinal cord

midbrain

one part of the brain stem, which serves as the passageway for electrical impusles as they travel between the brain and the spinal cord

migraine

a headache that produces intense throbbing and pain in one area of the head and that is typically accompanied by nausea and/or vomiting and hypersenitivity to light and sound

mitochondria

specialized tissue cells that ingest, digest, and convert nutrients into energy for the cells of the body

mood disorders

a group of mental disorders marked by depression that may alternate with periods of elation (feelings of happiness)

mood stabilizer

a drug used to balance brain chemicals that control emotional states and behaviors associated with certain mental disorders

motor neurons

neurons that recieve electrical impulses from the brain and spinal cord and communicate these impulses to other parts of the body

multiple sclerosis

a chronic, slow-progressing disease of the central nervous system marked by development of thin, demyelinated (without melanin) glial patches called *plaques*

myasthenia gravis (MG)

a disease of the skeletal muscles caused by disruption in neural communication between the muscles and the nerves; marked by severe weakness and fatigue

myelin sheath

a protective covering that is made up of fats and proteins and which surrounds the axons; provides electrical insulation

myelogram

a procedure in which an X-ray of the spinal cord is taken after a contrast agent (dye) has been injected into the spine