G

Gamma rays

Electromagnetic radiation of wave lengths shorter than x-rays which are given off by certain radioactive substances.

GABA

This stands for gammaaminobutyric acid. GABA is a neurotransmitter (a chemical that conveys messages within the nervous system) which controls the flow of nerve impulses by blocking the activity of other neurotransmitters.

Gene

A single component of the genetic message transmitted from parent to child.

General anaesthetic

A drug that is used to produce loss of consciousness and deaden or reduce sensation throughout the body for the purpose of performing an operation.

Generalised convulsion or seizure

This type of seizure, which arises over a wide area of the brain, causes loss of
consciousness and affects the whole body.

Genetic

This refers to the inherited instructions contained in the genes, which determine the activities of cells and therefore the development and functioning of the whole body.

Glaucoma

A condition in which vision is impaired because of abnormally high pressure in the eye.

Glial tissue

The special connective tissue of the central nervous system.

Glossopharyngeal

Relating to the tongue (glossa) and pharynx - the muscular tube which extends from the gullet up to the base of the skull and acts as a passageway for food and air.

Glossopharyngeal nerve

A nerve which conveys messages of sensation from the back of the throat to the brain.

Glycerol

A clear viscous liquid which has many uses in the pharmaceutical industry.

Gullet

Another name for the oesophagus, the muscular tube that carries food from the mouth to the stomach.

Global aphasia

A severe form of aphasia in which both understanding and expression of language are severely impaired.