Diabetes Glossary Terms: S-U

a roughly ovoid (egg-shaped) organ, coloured a deep purple, that is situated on the left of the body, behind and below the stomach. It is surrounded by a peritoneal membrane and contains a mass of lymphoid tissue. Macrophages in the spleen destroy microorganisms by phagocytosis. The spleen produces lymphocytes, leucocytes, plasma cells and blood platelets. It also stores red blood cells (erythrocytes) for use in emergencies. Release of red blood cells is facilitated by smooth muscle under the control of the sympathetic nervous system, and when this occurs, the familiar pain called stitch may be experienced. The spleen removes worn-out red blood cells, conserving the iron for further production in the bone marrow. Although the spleen performs many functions, it can be removed without detriment and as a result there is an increase in size of the lymphatic glands.

an expansion of the alimentary canal that lies between the oesophagus and the duodenum. It has thick walls of smooth muscle that contract to manipulate the food, and its exits are controlled by sphincters, the cardiac anteriorly and the pyloric at the junction with the duodenum. Mucosal cells in the lining secrete gastric juice. The food is reduced to an acidic semi-liquid that is moved on to the duodenum. The stomach varies in size but its greatest length is roughly 30 cm and the breadth 10 to 12 cm. Its capacity is approximately 1 to 1.5 litres.

a number of symptoms and signs that in combination together constitute a particular condition.

the male sex hormone secreted by the testes.

a bilobed endocrine gland situated at the base and front of the neck. It is enclosed by fibrous tissue and well supplied with blood, and internally consists of numerous vesicles containing a jelly-like colloidal substance. These vesicles produce thyroid hormone, which is rich in iodine, under the control of thyroid-stimulating hormone released from the pituitary gland. Two hormones are produced by the gland, thyroxine and triiodothyronine, which are essential for the regulation of metabolism and growth.

fats consisting of three fatty acid molecules combined with glycerol, which are the form in which the body stores fat. Triglycerides are derived from the digestion of fats in food.

a genetic disorder affecting females in which there is only one X-chromosome instead of the usual two. Those affected therefore have 45 instead of 46 chromosomes, are infertile (as the ovaries are absent), menstruation is absent and breasts and body hair do not develop. Those affected are short, may have webbing of the neck and other developmental defects. The heart may be affected and there can be deafness and intellectual impairment. In a less severe form of the disorder, the second X-chromosome is present but abnormal, lacking in normal genetic material.

a break on the skin surface or on the mucous membrane lining within the body cavities that may be inflamed and fails to heal. Ulcers of the skin include bedsores and varicose ulcers (which are caused by defective circulation).

the duct carrying urine from the bladder out of the body. It is about 3.5 cm long in women and 20 cm in men. The male urethra runs through the penis and also forms the ejaculatory duct.