Tumor
A mass of cells whose growth is uncontrolled and that serves no useful function
Malignant tumor
A cancerous tumor; lacks a distinct border and may metastasize; literally, "harm-producing
Benign tumor
A noncancerous tumor; has a distinct border and cannot metastasize; literally, "harmless
Metastasis
The process by which cells break off of a tumor, travel through the vascular system, and grow elsewhere in the body
Glioma
A cancerous brain tumor composed of one of several types of glial cells
Tumor initiating cells
Cells that originate from transformations of neural stem cells, rapidly proliferate, and give rise to a glioma
Meningioma
A benign brain tumor composed of the cells that constitute the meninges
Seizure disorder
The preferred term for epilepsy
Convulsion
A violent sequence of uncontrollable muscular movements caused by a seizure
Partial seizure
A seizure that begins at a focus and remains localized, not generalizing to the rest of the brain
Generalized seizure
A seizure that involves most of the brain, as contrasted with a partial seizure
Simple partial seizure
Type of partial seizure that causes changes in consciousness but not a loss of consciousness
Complex partial seizure
Type of partial seizure that causes a loss in consciousness
Grand mal seizure
The most severe form of seizure; a generalized, tonic-clonic seizure, which results in a convulsion
Aura
A sensation that precedes a seizure; its exact nature depends on the location of the seizure focus
Tonic phase
The first phase of a grand mal seizure, in which all of the patient's skeletal muscles are contracted
Clonic phase
The phase of a grand mal seizure in which the patient shows rhythmic jerking movements
Absence
A type of seizure disorder often seen in children; characterized by periods of inattention, which are not subsequently remembered; aka a petit mal seizure
Status epilepticus
A condition in which a patient undergoes a series of seizures without regaining consciousness
Hemorrhagic stroke
A cerebrovascular accident caused by the rupture of a cerebral blood vessel
Ischemic stroke
A cerebrovascular accident caused by occlusion of a blood vessel and interruption of the blood supply to a region of the brain
Thrombus
A blood clot that forms within a blood vessel, which may occlude it
Embolus
A piece of matter (such as a blood clot, fat, or bacterial debris) that dislodges from its site of origin and occludes an artery; in the brain, it can lead to a stroke
Free radical
A molecule with unpaired electrons; acts as a powerful oxidizing agent; toxic to cells
Fetal alcohol syndrome
A birth defect caused by ingestion of alcohol by a pregnant woman; includes characteristic facial anomalies and faulty brain development
Neural adhesion protein
A protein that plays a role in brain development; helps to guide the growth of neurons
Phenylketonuria
A hereditary disorder caused by the absence of an enzyme that converts the amino acid phenylalanine to tyrosine; the accumulation of phenylalanine causes brain damage unless a special diet is implemented soon after birth
Pyridoxine dependency
A metabolic disorder in which an infant requires larger-than-normal amounts of pyridoxine (vitamin B6) to avoid neurological symptoms
Galactosemia
An inherited metabolic disorder in which galactose (milk sugar) cannot easily be metabolized
Tay-Sachs disease
A heritable, fatal, metabolic storage disorder; lack of enzymes in lysosomes causes accumulation of waste product and swelling of cells of the brain
Down syndrome
A disorder caused by the presence of an extra twenty-first chromosome, characterized by moderate to severe mental retardation and often by physical abnormalities
Transmissible spongiform encephalopathy
A contagious brain disease whose degenerative process gives the brain a spongelike appearance; caused by accumulation of misfolded prion protein
Prion
A protein that can exist in two forms that differ only in their 3D shape; accumulation of misfolded prion protein is responsible for transmissible spongiform encephalopathies
Sporadic disease
A disease that occurs rarely that is not obviously caused by heredity or an infectious agent
Caspase
A "killer enzyme" that plays a role in apoptosis, or programmed cell death
Lewy bodies
Abnormal circular structures found in the cytoplasm of nigrostriatal neurons in people with Parkinson's disease
Toxic gain of function
Said of a genetic disorder caused by a dominant mutation that involves a faulty gene that produces a protein with toxic effects
Parkin
A protein that plays a role in ferrying defective or misfolded proteins to the proteasomes; mutated forms of this protein is a cause of familial Parkinson's disease
Loss of function
Said of a genetic disorder caused by a recessive gene that fails to produce a protein that is necessary for good health
Proteasome
An organelle responsible for destroying defective or degraded proteins within the cell
Ubiquitin
A protein that attaches itself to faulty or misfolded proteins and thus targets them for destruction by proteasomes
Deep brain stimulation
A surgical procedure that involves implanting electrodes in a particular region of the brain and attaching a device that permits the electrical stimulation of that region through the electrodes
Huntington's disease
An inherited disorder that causes degeneration of the basal ganglia; characterized by progressively more severe uncontrollable jerking movements, writhing movements, dementia, and finally death
Huntingtin
Abnormal forms of these proteins is the cause of Huntington's disease
Dementia
A loss of cognitive abilities such as memory, perception, verbal ability, and judgement; common causes are multiple strokes and Alzheimer's disease
Alzheimer's
A degenerative brain disorder of unknown origin; causes progressive memory loss, motor deficits, and eventual death
Encephalitis
An inflammation of the brain; caused by bacteria, viruses, or toxic chemicals
Herpes simplex virus
A virus that normally causes cold sores near the lips but that can also cause brain damage
Acute anterior poliomyelitis
A viral disease that destroys motor neurons of the brain and spinal cord
Rabies
A fatal viral disease that causes brain damage; usually transmitted through the bite of an infected animal
Meningitis
An inflammation of the meninges; can be caused by viruses or bacteria