Virtual Medical Centre

Sex cells, that is the cells which can be fertilised by gametes of the opposite sex. In females gametes are known as eggs, oocytes or ovum. In males gametes are known as sperm or spermatozoa.

More on male reproductive system.

More on female reproductive system.

Gamete intra-fallopian transfer (GIFT) is the transfer of viable oocytes and sperm into the fallopian tubes for fertilisation.

• genital warts
• HPV infection
• cervical, vulvar and vaginal cancers

A gastric tube is a tube inserted into the stomach to feed patients who cannot take food through their mouths.

Gastrointestinal means pertaining to the stomach or intestinal systems.

For more information, see the Gastrointestinal System.

Gastrointestinal lesions are wounds, ulcers or tissue damage occurring in the stomach.

Gastrointestinal stromal tumour is a cancerous tumour of the gastrointestinal tract.

Gastroscopy is endoscopic investigation of the upper gastrointestional tract.  See Oesophagogastroduodenoscopy (OGD).

Gaucher disease is a lysosomal storage disorder that is autosomal recessive and is characterised by a deficiency in the lysosomal enzyme glucocerebrosidase that is required in the breakdown of the glycolipid glucocerebroside (glucosylceramide).

More information on Gaucher disease.

Gelclair is a medical device used to reduce pain in patients with oral mucositis or other conditions that cause damage to the mucous membranes of the mouth. It is administered as a solution which is rinsed in the mouth. The solution adheres to the gums, tongue and other mucous membranes, creating a physical barrier that protects the damaged membranes from irritation.

For more information, see Gelclair.

Gene therapy involves the alteration of DNA to correct or prevent disease by inserting a gene artificially into the genome of an organism to correct a genetic defect.

A generic drug is a copy of the original branded drug.

Once the patent for the original product has run out, the pharmaceutical company who developed the branded drug no longer has the exclusive right to produce and distribute the medication, and other pharmaceutical companies are able to create their own version.

The generic drug uses the same active ingredient as in the original product, but the inactive ingredients are slightly different, the brand name will be different and the drug may look different.

For more information, see Generic and Branded Drugs.

If someone is said to have a genetic predisposition to a particular medical condition, disease or disorder it means that they may inherit the condition from relatives due to the passing on of DNA from one generation to the next.

Genital discharges are secretions from the penis or vagina. Many discharges occur normally, but discharges which are smelly or unusually coloured are commonly associated with sexually transmitted infections.

Genoptic is a medication used to treat infections of the eye and surrounding structures caused by susceptible bacteria.  Common types of infections include conjunctivitis, keratitis and keratoconjunctivitis, corneal ulcers, blepharitis and blepharoconjunctivitis, acute meibomianitis and dacryocystitis. It is also used as prophylaxis after surgery.

Gestational trophoblastic disease refers to a range of pregnancy related tumours.  The disease is commonly referred to as molar pregnancy.

More information Gestational trophoblastic disease

Gestational trophoblastic tumours are malignant (i.e. cancerous) forms of gestational trophoblastic disease, also known as gestational trophoblastic neoplasia.

More information on gestational trophoblastic disease

The glans penis is the enlarged tip (head) of the penis.

The Gleason score is a method of tumour classification used to classify the cancer into a stage which indicates how severe the cancer is and how likely it is that the treatment will be successful. The Gleason score is used to classify prostate cancer.

A numerical score is given to a cancer, from 2 to 10, which is the sum of two Gleason grades (depending on the level of changes the cells in the prostate cancer show). The Gleason score helps determine if a patient is suitable for high intensity focused ultrasound.

In addition to neurons, glial cells are the other major type of cells that make up the nervous system. They are also called neuroglia. Glial cells serve to protect and nourish the neurons. Neurons depend on glial cells to grow, nourish themselves, and establish effective synapses.

• Patients in chronic or accelerated phases of Philadelphia chromosome positive Chronic myeloid leukaemia (CML)
• Adult patients with a metastatic or unresectable malignant GI stromal tumour

Gluteal fat is fat that is stored around the hips and buttocks.

Gluten is a storage protein derived from wheat, barley, rye and a number of other cereals.

A gluten free diet is a diet in which all sources of the protein gluten are excluded. Practically, this means excluding wheat, rye, barley and a number of other cereals and their derivatives.

For more information, see Gluten Free Diet.

Gluten-sensitive enteropathy is a condition characterised by intolerance to gluten, also known as celiac disease.

More on Gluten Free Diet.

Glycol ethers are a group of solvents. They are most commonly found as ingredients in paint.

Gonadotrophins are hormones produced by the pituitary gland that act on the gonads (the sexual organs) to effect various endocrine functions. 

The Gordon Diagnostic System is a series of game-like tests that assess both attention and impulsivity. The system includes a "vigilance task", which shows the child a series of digits, one at a time. The child must identify every time a particular sequence of numbers appear (e.g. a 1 followed by a 9). This test is performed once visually, and once with the child listening to the numbers. There is also a test to check for impulsivity. The Gordon Diagnostic System has been validated for children between the ages of 4 and 16.

Graft-versus-host disease (GVHD) is a common complication of allogeneic bone marrow transplantation in which the transplanted marrow recognise the recipient as "foreign" and mount an immunologic attack.

Granulosa cells are oestrogen-secreting cells that help nourish the oocyte during its development by releasing estradiol. After ovulation the granulosa cells become luteal cells of the corpus luteum that produce progesterone. The release of this hormone from the corpus luteum helps maintain pregnancy in women and also produces a thick cervical mucus which inhibits sperm into the uterus.

Growth factors are those agents that stimulate epithelial proliferation. It can refer to medication or even naturally occurring substances in the body (usually proteins or steroids). They are important in maintaining cellular processes.

Growth hormone is a hormone produced by the pituitary gland. It plays a key role in the body's growth and development. An excess of growth hormone leads to the condition known as acromegaly, or gigantism. Artificial growth hormone may be administered as a drug in order to treat certain medical conditions (such as obesity).