largest portion of the brain, divided into left and right hemispheres. The cerebrum controls the skeletal muscles, interprets general senses (such as temperature, pain, and touch), and contains centers for sight and hearing. Intellect, memory, and emotional reactions also take place in the cerebrum.
spaces within the brain that contain a fluid called cerebrospinal fluid. The cerebrospinal fluid flows through the subarachnoid space around the brain and spinal cord.
located under the posterior portion of the cerebrum. Its function is to assist in the coordination of skeletal muscles and to maintain balance (also called hindbrain)
stemlike portion of the brain that connects with the spinal cord. Ten of the 12 cranial nerves originate in the brainstem.
located between the pons and spinal cord. It contains centers that control respiration, heart rate, and the muscles in the blood vessel walls, which assist in determining blood pressure.
cerebrospinal fluid (CSF)
clear, colorless fluid contained in the ventricles that flows through the subarachnoid space around the brain and spinal cord. It cushions the brain and spinal cord from shock, transports nutrients, and clears metabolic waste.
passes through the vertebral canal extending from the medulla oblongata to the level of the second lumbar vertebra. The spinal cord conducts nerve impulses to and from the brain and initiates reflex action to sensory information without input from the brain.
delicate middle layer of the meninges. The arachnoid membrane is loosely attached to the pia mater by weblike fibers, which allow for the subarachnoid space.
cordlike structure made up of fibers that carries impulses from one part of the body to another. There are 12 pairs of cranial nerves and 31 pairs of spinal nerves
specialized cells that support and nourish nervous tissue. Some cells assist in the secretion of cerebrospinal fluid and others assist with phagocytosis. They do not conduct impulses. Three types of glia are astroglia, oligodendroglia, and microglia. (also called neuroglia)
a nerve cell that conducts nerve impulses to carry out the function of the nervous system. Destroyed neurons cannot be replaced.
radic/o, radicul/o, rhiz/o
nerve root (proximal end of a peripheral nerve, closest to the spinal cord)
pertaining to the cerebrum, abnormal condition of a clot (blood clot in a blood vessel of the brain). (Onset of symptoms may appear from minutes to days after an obstruction occurs; a cause of ischemic stroke)
tumor composed of developing glial tissue (the most malignant and most common primary tumor of the brain)
tumor composed of the glial tissue (glioma is used to describe all primary neoplasms of the brain and spinal cord)
protrusion of the meninges and spinal cord (through a neural arch defect in the vertebral column) (also called myelomeningocele)
inflammation of the gray matter of the spinal cord. (This infectious disease, commonly referred to as polio, is caused by one of three polio viruses.)
disease of many nerves (most often occurs as a side effect of diabetes mellitus, but may also occur as a result of drug therapy, critical illness such as sepsis, or carcinoma; exhibiting symptoms of weakness, distal sensory loss, and burning)
pertaining to below the dura mater, tumor of blood (hematoma, translated literally, means blood tumor; however, a hematoma is a collection of blood resulting from a broken blood vessel)
disease characterized by early dementia, confusion, loss of recognition or persons or familiar surroundings, restlessness, and impaired memory
amyotrophic lateral sclerosis
progressive muscle atrophy caused by degeneration and scarring of neutrons along the lateral columns of the spinal cord that control muscles (also called Lou Gehrig disease)
paralysis of muscles on one side of the face, usually a temporary condition. Signs include a sagging a mouth on the affected side and nonclosure of the eyelid
an embolus (usually a blood clot or a piece of atherosclerotic plaque arising from a distant site) lodges in a cerebral artery, causing sudden blockage of blood supply to the brain tissue. A common cause of cerebral embolism, a type of ischemic stroke, is atrial fibrillation
condition characterized by lack of muscle control and partial paralysis, caused by a brain defect or lesion present at birth or shortly after
cognitive impairment characterized by a loss of intellectual brain function. Patients have difficulty in various ways, including difficulty in performing complex tasks, reasoning, learning, and retaining new information, orientation, word finding, and behavior. Dementia has several causes and is not considered part of normal aging.
condition characterized by recurrent seizures; a general term given to a group of neurologic disorders, all characterized by abnormal electrical activity in the brain
increased amount of cerebrospinal fluid in the ventricles of the brain, which can cause enlargement of the cranium in infants
bleeding into the brain as a result of a ruptured blood vessel within the brain. Symptoms vary depending on the location of the hemorrhage; acute symptoms include dyspnea, dysphagia, aphasia, diminished level of consciousness, and hemiparesis. The symptoms often develop suddenly. Intracerebral hemorrhage, a cause of hemorrhagic stroke, is frequently associated with high blood pressure.
multiple sclerosis (MS)
degenerative disease characterized by sclerotic patches along the brain and spinal cord. Signs and symptoms are variable and fluctuate over the course of the disease. More common symptoms include fatigue, balance and coordination impairments, numbness, and vision problems.
chronic degenerative disease of the central nervous system. Signs and symptoms include resting tremors of the hands and feet, rigidity, expressionless face, and shuffling gait. It usually occurs after the age of 50 years.
inflammation of the sciatic nerve, causing pain that travels from the thigh through the leg to the foot and toes; can be caused by injury, infection, arthritis, herniated disk, or from prolonged pressure on the nerve from sitting for long periods
viral disease that affects the peripheral nerves and causes blisters on the skin that follow the course of the affected nerves (also called herpes zoster)
occurs when there is an interruption of blood supply to a region of the brain, depriving nerve cells in the affected area of oxygen and nutrients. The cells cannot perform and may be damaged or die within minutes. The parts of the body controlled by the involved cells will experience dysfunction. Speech, movement, memory, and other CNS functions may be affected in varying degrees. Ischemic stroke is a result of a blocked blood vessel. Hemorrhagic stroke is a result of bleeding. (also called cerebrovascular accident [CVA] or brain attack
bleeding caused by a ruptured blood vessel just outside the brain (usually a ruptured cerebral aneurysm) that rapidly fills the space between the brain and skull (subarachnoid space) with blood. The patient may experience an intense, vomiting, and neck pain (a cause of hemorrhagic stroke)
transient ischemic attack (TIA)
sudden deficient supply of blood to the brain lasting a short time. The symptoms may be similar to those of stroke, but with TIA the symptoms are temporary and the usual outcome is complete recovery. TIAs are often warning signs for eventual occurrence of a stroke
radiographic imaging of the blood vessels in the brain (after an injection of contrast medium)
process of recording (scan) the spinal cord (after an injection of a contrast agent into the subarachnoid space by lumbar puncture. Size, shape, and position of the spinal cord are nerve roots are demonstrated.)
computed tomography of the brain (CT scan)
process that includes the use of a computer to produce a series of brain tissue images at any desired depth. The procedure is painless and particularly useful in diagnosing brain tumors
magnetic resonance imaging of the brain or spine (MRI scan)
a noninvasive technique that produces sectional images of soft tissues of the brain or spine through a strong magnetic field. Unlike a CT scan, MRI produces images without use of radiation. It is used to visualize tumors, edema, multiple sclerosis, and herniated disks
positron emission tomography of the brain (PET scan)
nuclear medicine imaging technique with a radioactive substance that produces sectional imaging of the brain to examine blood flow and metabolic activity. Images are projected on a viewing screen.
evoked potential studies (EP studies)
a group of diagnostic tests that measure changes and responses in brain waves elicited by visual, auditory, or somatosensory stimuli. Visual evoked response (VER) is a response to visual stimuli. Auditory evoked response (AER) is a response to auditory stimuli.
lumbar puncture (LP)
insertion of a needle into the subarachnoid space usually between the third and fourth lumbar vertebrae. It is performed for many reasons, including the removal of cerebrospinal fluid for diagnostic purposes (also called spinal tap)
paralysis of half (right or left side of the body); stroke is the most common cause of hemiplegia
abnormal sensation (such as burning, prickling, or tingling sensation, often in the extremities; may be caused by nerve damage or peripheral neuropathy)
conveying toward a center (for example, afferent nerves carry impulses to the central nervous system)
injury to the brain caused by major or minor head trauma; symptoms include vertigo, headache, and possible loss of consciousness.
the inability to use speech that is distinct and connected because of a loss of muscle control after damage to the peripheral or central nervous system
conveying away from the center (for example, efferent nerves carry information away from the central nervous system)
sudden surge of abnormal electrical activity in the brain, resulting in involuntary body movements or behaviors
state of being unaware of surroundings and incapable of responding to stimuli as a result of injury, shock, illness, or drugs
specialty of the mind (branch of medicine that deals with the treatment of mental disorders)
study of the mind (a profession that involves dealing with the mind and mental processes in relation to human behavior)
psychosis (pl. psychoses)
abnormal condition of the mind (major mental disorder characterized by extreme derangement, often with delusions and hallucinations
an eating disorder characterized by a disturbed perception of body image resulting in failure to maintain body weight, intensive fear of gaining weight, pronounced desire for thinness, and, in females, amenorrhea
an emotional disorder characterized by feelings of apprehension, tension, or uneasiness arising typically from the anticipation of unreal or imagined danger
attention deficit hyperactivity disorder (ADHD)
a disorder of learning and behavioral problems characterized by marked inattention, distractability, impulsiveness, and hyperactivity
a spectrum of mental disorders, the features of which include onset during the infancy or childhood, preoccupation with subjective mental activity, inability to interact socially, and impaired communication
a major psychological disorder typified by a disturbance in mood. The disorder is manifested by manic and depressive episodes that may alternate or elements of both may occur simultaneously.
an eating disorder characterized by uncontrolled binge eating followed by purging (induced vomiting)
a mood disturbance characterized by feelings of sadness, despair, discouragement, hopelessness, lack of joy, altered sleep patterns, and difficulty with decision making and daily function. Depression ranges from normal feelings of sadness (resulting from and proportional to personal loss or tragedy), through dysthymia (chronic depressive neurosis), to major depression (also referred to as clinical depression, mood disorder).
obsessive-compulsive disorder (OCD)
a disorder characterized by intrusive, unwanted thoughts that result in the tendency to perform repetitive acts or rituals (compulsions), usually as a means of releasing tension or anxiety
an episode of sudden onset of acute anxiety, occurring unpredictably, with feelings of acute apprehension, dyspnea, dizziness, sweating, and/or chest pain, depersonalization, paresthesia and fear of dying, loss of mind or control
a marked and persistent fear that is excessive or unreasonable cued by the presence or anticipation of a specific situation or object (such as claustrophobia, the abnormal fear of being in enclosed spaces)
compulsive eating of nonnutritive substances such as clay or ice. This condition is often a result of an iron deficiency. When iron deficiency is the cause of pica the condition will disappear in 1 or 2 weeks when treated with iron therapy.
posttraumatic stress disorder (PTSD)
a disorder characterized by an acute emotional response to a traumatic event perceived as life threatening or severe emotional stress such as an airplane crash, repeated physical or emotional trauma, or military combat. Symptoms incude anxiety, sleep disturbance, nightmares, difficulty concentrating, and depression.
any one of a large group of psychotic disorders characterized by gross distortions of reality, disturbance of language and communication, withdrawal from social interaction, and the disorganization and fragmentation of thought, perception, and emotional reaction
disorders characterized by physical symptoms for which no known physical cause exists