In alphabetical order

Alpha Receptors: Found primarily in the smooth muscle tissue of peripheral blood vessels and in the sphincters of the gastrointestinal and genitourinary tracts. Stimulation of the alpha receptors causes contraction of these smooth muscles, which may result in an increase in blood pressure due to constriction of peripheral blood vessels.

Amnesia: Partial or total memory loss usually due to brain injury, illness, or psychological disturbances.

Amyotrophic Lateral Sclerosis: Also known as ALS (Lou Gehrig's disease). It is a degenerative disease of the motor neurons.

Aphasia: A condition that is due to brain damage. It's the loss of the ability to speak, write, or comprehend the written or spoken word.

Apraxia: An impairment in the ability to perform purposeful acts or to properly use familiar objects.

Athetosis: A condition of constant involuntary movements (usually of the upper extremities) that are slow, irregular and snake-like.

Axon: Extends away from the cell body and conducts impulses away from the nerve cell. Some axons, but not all, are protected by a white fatty tissue covering called myelin.

Bell's Palsy: Paralysis of the facial (seventh cranial) nerve that causes a unilateral distortion of the affected side of the face.

Beta Receptors: Located primarily in the muscles of the heart and in fatty tissue. Stimulation of these receptors in the heart produces a more rapid heart rate and more forceful heart muscle contractions.

Brain: The primary center that regulates and coordinates your body's activities. Each part of the brain controls different aspects of your body's functions. It's the portion of the brain and spinal cord (central nervous system) that's contained inside the skull.

Causalgia: An intense burning pain following an injury to a sensory nerve.

Cephalalgia and Cephalodynia: A headache or pain in the head.

Cerebral Anoxia: An abnormal condition in which oxygen is deficient in brain tissue. If this condition continues for more than four to six minutes, irreversible brain damage may occur.

Cerebral Contusion: A bruising of brain tissue as a result of a head injury.

Cerebral Palsy: A motor function disorder caused by a permanent, non-progressive brain defect or lesion present at birth or shortly thereafter. It is characterized by spasticity, athetosis, tremors, and loss of muscle tone.

Cerebellum: The second largest part of the brain, located beneath the posterior part of the cerebrum.

Cerebrum: The largest portion of the brain. It is responsible for all thought, judgment, memory association and discrimination. The cerebrum is the uppermost portion of the brain. It is divided at the very top, forming the left and right hemispheres. Each hemisphere is divided into four lobes (frontal, occipital, parietal and temporal).

Cerebrospinal Fluid: This is a clear, colorless, watery fluid produced by special capillaries within the ventricles of the brain. The fluid flows throughout the brain and around the spinal cord, and functions to cushion for these organs from shock or injury.

Cerebrovascular Accident: Also known as a stoke or apoplexy, is the general term used to indicate that the blood supply to a portion of the brain has been suddenly shut off.

Chemonucleolysis: The process of dissolving part of the nucleus of an intervertebral disk by the injection of a chemolytic agent.

Coma: A profound (deep) state of unconsciousness characterized by the absence of spontaneous eye movements, response to painful stimuli, and vocalization. Comatose refers to one who is in a coma.

Concussion: This is sometimes referred to as a brain concussion or a cerebral concussion. It is a violent shaking or jarring of the brain caused by a direct blow or explosion.

Cranial Hematoma: A collection of blood trapped in the tissues of the brain. Cranial hematomas include epidural hematoma, subdural hematoma, and intracerebral hematoma.

Cranial Nerves: The 12 pairs of cranial nerves originate from the undersurface of the brain and are arranged in identical pairs so both nerves of a pair are identical in function and structure. The cranial nerves are generally named for the area or function they serve and are identified with Roman numerals.
I Olfactory Nerves conduct impulses from receptors in the nose to the brain and are sensory in function.
II Optic Nerves conduct impulses from receptors in the eyes to thebrain and are sensory in function.
III Oculomotor Nerves send motor impulses to four of the external eye muscles and to certain internal eye muscles.
IV Trochlear Nerves send motor impulses to one external eye muscle of each eye.
V Trigeminal Nerves each divide into three branches: Ophthalmic branches go to the eyes and forehead. Maxillary branches go to the upper jaw. Mandibular branches go to the lower jaw.
VI Abducens Nerves innervate the muscles that turn the eye to the side.
VII Facial Nerves innervate the facial muscles, salivary glands, lacrimal glands, and the sensation of taste on the anterior two-thirds of the tongue.
VIII Acoustic Nerves each divide into two branches: Cochlear branches are concerned with the sense of hearing. Vestibular branches are concerned with the sense of balance.
IX Glossopharyngeal Nerves innervate the parotid glands and the sense of taste on the posterior third of the tongue and part of the pharynx.
X Vagus Nerves innervate part of the pharynx, larynx, vocal cords, and parts of the thoracic and abdominal viscera.
XI Spinal Accessory Nerves innervate the shoulder muscles. Some fibers of these nerves arise from the spinal cord.
XII Hypoglossal Nerves primarily innervate the muscles concerned with movements of the tongue.

Craniectomy: The surgical removal of a portion of the skull.

Craniocele: The herniation of brain substance through the skull.

Cranioplasty: The surgical repair of the skull.

Craniotomy: A surgical incision or opening into the skull.

Delirium: A mental state in which one experiences confusion and decreased awareness of surroundings.

Diskectomy: The surgical removal of an intervertebral disk.

Dysphasia: An impairment of speech due to a brain lesion. (A lesion is an injury or pathological change in the tissue.)

Echoencephalography: This is a diagnostic technique in which pulses of ultrasonic waves are beamed through the head from both sides.

Electroencephalography: This procedure is also known as EEG. It is the process of recording brain wave activity. The resulting record is called an electroencephalogram.

Encephalography: This is an x-ray study demonstrating the intracranial fluid-containing spaces of the brain. The resulting record is called an encephalogram.

Encephalitis: An inflammation of the brain.

Encephalopathy: Any degenerative disease of the brain.

Epilepsy: A group of neurologic disorders characterized by recurrent episodes of convulsive seizures and related disturbances characterized by petit mal or grand mal seizures.

Fissure: Also known as sulci, are the normal depressions or grooves of the cerebral cortex.

Frontal Lobe: Controls motor functions.

Ganglion: A knot-like mass or group of nerve cell bodies located outside the central nervous system.

Grand Mal Seizure: Involves generalized involuntary muscular spasms.

Hallucination: A sense perception (sight, touch, sound, smell, or taste) that has no basis in external stimulation.

Hydrocephalus: An abnormally increased amount of cerebrospinal fluid within the brain.

Hyperesthesia: A condition of excessive sensitivity to stimuli.

Innervation: The supply of nerves to a body part. It also means the stimulation of a body part through the action of nerves.

Laminectomy: The surgical removal of a spinal lamina.

Lethargy: A state of being indifferent, apathetic, or sluggish.

Macroencephaly: A condition in which the head is abnormally large.

Meninges: Three layers of connective tissue membrane that enclose the brain and spinal cord.

Meningitis: An inflammation of the meninges of the brain or spinal cord.

Meningopathy: Any disease of the meninges.

Microencephaly: A condition in which the head is abnormally small.

Migraine Headache: A syndrome characterized by sudden, severe, sharp headache usually present only on one side.

Multiple Sclerosis: A progressive disease characterized by scattered patches of demyelination of nerve fibers of the brain and spinal cord. Demyelination is the destruction or loss of the myelin sheath from myelinated fibers.

Myelin Sheath: The protective covering over some nerve cells, including parts of the spinal cord, the white matter of the brain, and most peripheral nerves. The myelin sheath gives these nerve fibers a white color, and myelinated nerves are referred to as "white matter". Myelinated means having a myelin sheath. Nerves that do not have the myelin sheath are gray, and they make up the "gray matter" of the brain and spinal cord.

Myelitis: An inflammation of the spinal cord.

Myelography: The diagnostic study of the spinal cord after injecting a contrast medium. The resulting record is called a myelogram.

Myelosis: Means a tumor of the spinal cord. However, it also means an abnormal proliferation of bone marrow tissue.

Narcolepsy: A syndrome characterized by recurrent uncontrollable seizures of drowsiness and sleep.

Nerve: One or more bundles of impulse carrying fibers that connect the brain and spinal cord with other parts of the body.

Nervous System: The nervous system is often described as being divided into the following parts: Central Nervous System that consists of the brain and spinal cord. Peripheral Nervous System that consists of the cranial nerves (extending from the brain) and spinal nerves (extending from the spinal cord). Autonomic Nervous System that consists of ganglia on either side of the spinal cord.

Neuralgia: Pain in a nerve or nerves.

Neuritis: An inflammation of a nerve or nerves. (The term neuritis and neuralgia are often used interchangeably.)

Neuropathy: Any disease of the nervous system.

Neurotransmitter: A neurotransmitter is a chemical substance that makes it possible for the impulse to jump across the synapse from one neuron to another.

Neuroglia: The supportive and connective cells of the nervous system. Sometimes called "nerve glue".

Neuron: The basic cell of the nervous system. The three types of neurons are described according to their function. Efferent neurons, also known as "motor neurons", carry impulses away from the brain and spinal cord and toward the muscles and glands. Afferent neurons, also known as "sensory neurons", emerge from the skin or sense organs and carry impulses toward the brain and spinal cord. Connecting neurons, also called "associative neurons", carry impulses from one neuron to another. Each neuron consists of a cell body, several dendrites, a single axon, and terminal end fibers.

Occipital Lobe: Controls eyesight.

Paresthesia: An abnormal sensation, such as burning, tingling, or numbness, for no apparent reason.

Parkinson's Disease: A slowly progressive, degenerative neurologic disorder characterized by stiffness, slowed movements, and rhythmic fine tremors.

Parietal Lobe: Receives and interprets nerve impulses from the sensory receptors.

Percutaneous Diskectomy: A procedure where a thin tube is inserted through the skin of the back to suck out the ruptured disk or to vaporize it with a laser.

Peripheral Nervous System: Includes the cranial and spinal nerves.

Petit Mal Seizure: A sudden, momentary loss of conciousness.

Poliomyelitis: This condition is also known as polio. It is a viral infection of the gray matter of the spinal cord that may result in paralysis. Individuals who have had poliomyelitis, and have recovered from it, may suffer from the post-polio syndrome which is the recurrence later in life of some polio symptoms.

Pons: The part of the brain stem situated at the base of the brain where nerve cells cross from one side of the brain to control the opposite side of the body.

Radiculitis: An inflammation of the root of a spinal nerve, especially that portion of the root that lies between the spinal cord and intervertebral canal.

Receptors: The sensory organs (eyes, ears, skin, and taste buds) that receive external stimulation and transmit it to the sensory neurons.

Seizure: Also known as a convulsion, is a sudden, violent, involuntary contraction of a group of muscles. It may be accompanied by a loss of consciousness.

Sciatica: An inflammation of the sciatic nerve that may result in pain along the course of the nerve through the thigh and leg.

Somnambulism: Also known as noctambulism or sleepwalking, is the condition of walking without awakening.

Somnolence: Sleepiness and also an unnatural drowsiness. A somnolent person can usually be aroused by verbal stimuli.

Spasticity: Uncontrolled contractions of the skeletal muscles.

Spinal Nerves: Consists of 31 pairs of nerves and are usually named after the artery they accompany or the body part they innervate.

Stupor: A state of lethargy and unresponsiveness in which a person seems unaware of surroundings.

Sympathetic Nervous System: The sympathetic division of the autonomic nervous system is concerned with body functions under stress. Receptors in the sympathetic nervous system are classified as being alpha or beta receptors.

Synapse: The space between two neurons or between a neuron and receptor organ.

Syncope: Also known as fainting, is a brief loss of consciousness caused by transient cerebral hypoxia. (Hypoxia is a lack of cellular oxygen.)

Temporal Lobe: Controls the senses of hearing and smell.

Tic Douloureux: Also known as trigeminal neuralgia or trifacial neuralgia, is an inflammation of the trigeminal (fifth cranial) nerve. It is characterized by sudden, intense, sharp pain on one side of the face.

Tremor: Involuntary shaking or trembling of the body or any of its parts.

Ventricle: A small cavity, such as the ventricles of the brain and heart.

Ventriculography: This is a form of encephalography. It's a procedure for the radiographic visualization of the head after the injection of air or another contrast medium into the cerebral ventricles. Ventriculography also describes a radiographic study of a heart ventricle after the injection of a contrast medium.

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