A

  • A - noun- a human blood type of the ABO system, containing the A antigen (NOTE: Someone with type A can donate to people of the same group or of the AB group and can receive blood from people with type A or type O.)

  • AB -noun- a human blood type of the ABO system, containing the A and B antigens (NOTE: Someone with type AB can donate to people of the same group and receive blood from people with type O, A, AB or B.)

  • Abdominal viscera The organs which are contained in the abdomen, e.g. the stomach, liver, and intestines

  • Abscess A localized collection of pus in a cavity formed by the disintegration of tissues.

  • Achalasia Failure to relax; especially referring to smooth muscle fibers at any junction of the gastrointestinal tract (e.g. openings such as the pylorus, cardia or other sphincter muscles); especially failure of the esophageal sphincter to relax with swallowing.

  • Acinus (acini = pl.) A small sac-like dilatation, e.g. in the lung the basic unit of gas exchange, each acinus is supplied by a single terminal bronchiole; in the liver, the smallest functional unit.

  • Acute a disease with sudden onset of signs and a short course.

  • Adenocarcinoma a malignant tumour originating in glandular tissue.

  • Allergy A reaction in the body to a substance, which itself is usually not harmful (for example, pollen, peanuts, pets). Symptoms may be mild (a runny nose or itchy eyes) or life-threatening (collapse or inability to breath). Allergy is very common, 1 in 4 people in the UK will have an allergic reaction at some time in their lives. The doctors who specialise in the diagnosis and treatment of allergies are immunologists and allergists, although other specialties such as dermatologists have expertise in allergies affecting their organ of interest. Although approximately 11% of GP prescriptions are for allergies, there are very few immunologists or allergists in the UK.

  • Antibiotics A group of drugs that kill bacteria and some other infective organisms but have no effect on viruses, which cause the common cold and ‘flu’. Examples of antibiotics include penicillin, cephalexin, ciprofloxacin, trimethoprim and tetracycline. Examples of infections that can be treated with antibiotics include some kinds of meningitis, pneumonia and urinary infections.

  • Antibody Antibodies are Y-shaped proteins that form part of the body's immune defences. They are produced by specialised white blood cells called plasma cells and bind to foreign proteins, called antigens. Antibodies are usually made in response to foreign materials such as bacteria or chemicals, but sometimes the body makes antibodies to its own proteins. This results in autoimmune disease.

  • abdomen a space inside the body below the diaphragm, above the pelvis and in front of the spine, containing the stomach, intestines, liver and other vital organs pain in the abdomen (NOTE: For other terms referring to the abdomen, see words beginningwith coeli-, coelio-.) COMMENT: The abdomen is divided for medical purposes into nine regions: at the top, the right and left hypochondriac regions with the epigastrium between them; in the centre, the right and left lumbar regions with the umbilical between them; and at the bottom, the right and left iliac regions with the hypogastrium between them.

  • abdominal located in the abdomen, or relating to the abdomen

  • abdominal aorta The part of the aorta which lies between the diaphragm and the point where the aorta divides into the iliac arteries. See illustration at KIDNEY in Supplement

  • abdominal cavity The space in the body below the chest

  • abdominal distension A condition in which the abdomen is stretched because of gas or fluid

  • abdominal pain Pain in the abdomen caused by indigestion or more serious disorders

  • abdominal wall Muscular tissue which surrounds the abdomen

  • abdomino- referring to the abdomen

  • abdominopelvic Referring to the abdomen and pelvis

  • abdominoperineal Referring to the abdomen and perineum

  • abdominoperineal excision a surgical operation that involves cutting out tissue in both the abdomen and the perineum

  • abdominoposterior Referring to a position of a fetus in the uterus, where the fetus’s abdomen is facing the mother’s back