Medical terms - Letter G | MedicalVocabulary.org

G

G stands for guanine, one member of the base pair G-C (guanine-cytosine) in the DNA. The other base pair in the DNA is A-T (adenine-thymine). Each base pair forms a 'rung of the DNA ladder.' A DNA nucleotide is made of…
G (drug caution code)

Abbreviation on a medication that stands for 'glaucoma' and indicates the medication can cause problems for a person with this eye disorder. Further, a person with glaucoma might see the generic 'C' code on a…
G (gram)

Symbol for gram, a unit of measurement of weight and mass in the metric system. In weight, a gram is equal to a thousandth of a kilogram. In mass, a gram is equal to a thousandth of a liter (one cubic centimeter) of…
G protein

These molecules have been described as 'biological traffic lights.' Located inside the cell, G proteins are able respond to signals outside the cell -- light, smell, hormones -- and translate (transduce) these signals…
G-CSF

Granulocyte colony-stimulating factor. A colony-stimulating factor that stimulates the production of neutrophils (a type of white blood cell). G-CSF is a cytokine that belongs to the family of drugs called hematopoietic…
G6PD deficiency

G6PD deficiency: Deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), the most common enzyme defect of medical importance. About 10 percent of American black males have G6PD deficiency, as do a lesser…
GAD

Generalized anxiety disorder
Gage, Phineas

The most famous patient to have survived severe damage to the brain and the first from whom something was learned about the relation between personality and the function of the front parts (the frontal lobes) of the…
Gain-of-function mutation

A mutation that confers new or enhanced activity on a protein. Loss-of-function mutations, which are more common, result in reduced or abolished protein function
Gait

A manner of walking. Observation of the gait can provide clues to a number of diagnoses including Parkinson disease, cerebral palsy, congenital dislocation of the hip, and stroke
Gait, steppage

See Steppage gait
Galactorrhea

The spontaneous flow of milk from the nipple at any time other than during nursing. Galactorrhea can be due to 'normal' factors such as an unrecognized pregnancy, trauma, surgery, overexercise or one of a number of…
Galactose

A sugar contained in milk. Galactose makes up half of the sugar called lactose that is found in milk. Lactose is called a disaccharide, di meaning 2, since lactose is made up of two sugars, galactose and glucose, bound…
Galactosemia

A genetic metabolic disease in which there is a defect in the body's ability to use the sugar galactose. In classic galactosemia, the basic defect is a deficiency of the enzyme known as GALT (galactose-1-phosphate…
Galen

Greek physician and philosopher (born about 129 AD, died about 210 AD) known among other things for his discovery of blood in human arteries and for his dissection of the human cranial nerves, the nerves that supply key…
Galenic arteriovenous malformation

See: Vein of Galen aneurysm
Galeophobia

An abnormally large and persistent fear of sharks. Sufferers from this phobia experience anxiety even though they may be safe on a boat or in an aquarium or on a beach. Hollywood films depicting sharks as calculating…
Gallbladder

A pear-shaped organ just below the liver that stores the bile secreted by the liver. During a fatty meal, the gallbladder contracts, delivering the bile through the bile ducts into the intestines to help with digestion…
Gallbladder absence

This condition, also known as agenesis (failure of development) of the gallbladder, occurs in approximately one out of every 1,000 people. Gallbladder agenesis is an isolated abnormality in more than two-thirds (70%) of…
Gallbladder agenesis

This is a condition in which the gallbladder fails to develop. This happens in approximately one out of every 1,000 people. Gallbladder agenesis is an isolated finding in more than two-thirds (70%) of people. The person…
Gallium

A rare metal with the atomic weight of 69. There are several isotopic forms of gallium that differ from it in atomic weight. One is gallium-68 which is produced by cyclotrons and emits gamma rays. The citrate form of…
Gallop rhythm

Heart rhythm like the gallop of a horse.
Gallstone pancreatitis

Pancreatitis: Gallstone-induced pancreatitis. Pancreatitis due to gallstones
Gallstones

Gallstones: Stones that form when substances in the bile harden. Gallstones can be as small as a grain of sand or as large as a golf ball. There can be just one large stone, hundreds of tiny stones, or any combination…
Gallstones and ERCP

A mixture of microscopic particulate matter in bile, also called biliary sludge, that occurs when particles of material precipitate from bile. (Bile is the fluid that is made by the liver. It is stored in the…
Gallstones, microscopic

Gallstones, microscopic: A mixture of microscopic particulate matter in bile, also called biliary sludge, that occurs when particles of material precipitate from bile. (Bile is the fluid that is made by the liver. It is…
Gallus gallus

The Red Jungle Fowl, the ancestor of domestic chickens
Gallus gallus genome

The genome of the Red Jungle Fowl, the ancestor of domestic chickens. See: Chicken genome
GALT

The enzyme (galactose-1-phosphate uridyl transferase) lack of which causes the genetic metabolic disease called galactosemia. GALT is also the symbol for the gene that encodes the enzyme
GALT deficiency

Lack of the enzyme called GALT (galactose-1-phosphate uridyl transferase) which causes the genetic metabolic disease galactosemia, one of the diseases in many newborn screening panels. The disease can be fatal, if…
Galton, Sir Francis

English advocate of eugenics, the idea of improving the physical and mental makeup of the human species by selective parenthood. Galton coined the word 'eugenics' to denote scientific endeavors to increase the…
Gamete

The sperm or the egg. Each human gamete normally has 23 chromosomes, the haploid number of chromosomes, half the number of chromosomes contained in most types of cells in the body
Gamete intrafallopian transfer (GIFT)

A technique in which the male and female germ cells required to begin formation of a human embryo are injected into a woman's fallopian tubes of the female for fertilization. This technique is one of the methods doctors…
Gametic

Pertaining to the gamete (the sperm or eggs)
Gametic selection

Preferential selection of gametes (germ cells -- sperm or eggs). Gametic selection is a mechanism of transmission distortion
Gametogenesis

The development and production of the male and female germ cells required to form a new individual. The male and female germ cells are called gametes. The gametes in human males are produced by the testes, two…
Gametophobia

An abnormal and persistent fear of being married. Sufferers of gametophobia experience undue anxiety even though they may rationally realize that the married state itself poses no threat to them. They may fear the…
Gamma globulin

A major class of immunoglobulins found in the blood, including many of the most common antibodies circulating in the blood. Also called immunoglobulin G (IgG).
Gamma hydroxybutyrate (GHB)

Known in Europe as Gamma-OH, gamma hydroxybutyrate is a colorless and odorless drug used illicitly for 'recreational' purposes and for 'date rape.' GBH is a central nervous system depressant. It tends therefore to…
Gamma knife

A type of radiosurgery (radiation therapy) machine that acts by focusing low-dosage gamma radiation from many sources on a precise target. Areas adjacent to the target receive only slight doses of radiation, while the…
Gamma linolenic acid

See: Gamma-linolenic acid
Gamma ray

High-energy electromagnetic radiation emitted by certain radionuclides when their nuclei transition from a higher to a lower energy state. Gamma rays have high energy and a short wave length. All gamma rays emitted from…
Gamma-linolenic acid

Abbreviated GLA. An essential polyunsaturated fatty acid contained in some plant seed oils including evening primrose oil, black currant oil, and borage oil. GLA has been used for a number of different disorders. GLA is…
Gamma-OH

A European name for gamma hydroxybutyrate (GHB), a colorless and odorless drug used illicitly for 'recreational' purposes and for 'date rape.' GBH is a central nervous system depressant. It tends therefore to increase…
Ganglia, basal

A region located at the base of the brain composed of 4 clusters of neurons, or nerve cells. This area of the brain is responsible for body movement and coordination. The groups of neurons most prominently and…
Ganglion

Ganglion: The celebrated 2nd century Greek physician Galen ((c. 130-201 A.D.) who lived and worked in Rome first used the word ganglion to denote a nerve complex. Ganglion still is used to refer to an aggregation of…
Gangrene

The death of body tissue due to the loss of blood supply to that tissue, sometimes permitting bacteria to invade it and accelerate its decay. The word 'gangrene' comes from the Greek 'ganggraina' denoting 'an eating…
Gap junction

An organized collections of protein channels in cell membranes that allows ions and small molecules to pass between adjacent cells. The protein channels that make up gap junctions consist of two connexons. One connexon…
Gap junction beta 2

See: GJB2
Gareis-Mason syndrome

An inherited (genetic) syndrome with characteristic features including (1) neurologically: mental retardation and aphasia (lack of speech); (2) limbs: adducted (clasped) thumbs, absent extensor pollicis longus and/or…