Medical dictionary

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Labile: unstable.
Laceration: tear.
Lacrimal: tear-related.
Lactase an enzyme that acts as a catalyst to convert lactose into glucose and galactose.
Lactation: milk production.
Lactic acid: a weak acid produced by cells when they break down glucose to produce energy by anaerobic metabolism.
Lactose: a type of sugar found in milk and milk products.
Lactose intolerance: the inability to digest milk products due to the lack of the enzyme lactase, which breaks down milk sugar (lactose).
Laminectomy: surgical procedure which is designed to relieve pressure on the spinal cord or nerve root that is being caused by a slipped or herniated disk in the lumbar spine.
Laparoscope: an endoscope for the abdominal region of the body.
Laparoscopy: abdominal keyhole surgery.
Laparotomy: any operation that involves opens up ingthe abdomen.
Large granular lyphocytic leukaemia: a chronic leukaemia which affects t-cells.
Laryngitis: sore throat caused by inflammation of the larynx.
Larynx: the 'voice-box' in the neck.
Lassitude: wearniness.
Latency: a quiescent period during a disease process.
Latent period: inactive period.
Lateral: towards the side.
Lavage: a cleaning of the stomach and colon.
Laxative: medicine to relieve constipation.
LDL: low density lipoprotein cholesterol, the "bad" cholesterol believed to be linked to fat accumulation in the arteries.
Lenticular: lense-related.
Leprosy: a contagious disease caused by Mycobacterium leprae.
Leptospirosis: infectious disease caused by infection with Leptospira.
Lesion: a disturbed area of tissue -- a wound, injury, nodule or tumour on the skin or elsewhere.
Leukaemia: from the greek meaning "white blood". Often referred to as cancer of the blood. Characterised by the widespread uncontrolled proliferation of large numbers of abnormal blood cells, usually of the white cell lineages, which take over the bone marrow and often spill out into the blood stream.
Leukaemogenesis: the development of leukaemia.
Leukapheresis: method of separating blood into its liquid and cellular components and for the removal of white blood cells before returning the remainder of the blood to the patient. It is used to reduce the white cell count when chemotherapy is to be avoided, for example during pregnancy.
Leukocyte: white blood cell.
Leukocytosis: increased white blood cell count.
Leukopaenia: condition in which the number of white cells in the blood is greatly reduced. Leads to an increased risk of infections.
Leukoplakia: white patch on a mucous membrane.
Leukorrhoea: vaginal discharge.
Lice: head lice are the most common kind of lice to infect humans. They are sometimes called nits, which is actually the name of the tiny white eggs they hatch from.
Lichenification: skin hardening and thickening.
Lichen sclerosus: a poorly recognised skin condition which mainly affects the vulval and perianal area.
Ligament: short band of tough, flexible, fibrous connective tissue which link bones together and make the joint stable. Each joint has several ligaments.
Light therapy: bright light can be used to reset the biological clock. Light therapy, as currently used, refers to treatments that increase production of Vitamin D (thus aiding absorption of some minerals).
Limbic: edge-related.
Lineage: describes cells with a common ancestry, that is developing from the same type of identifiable immature cell.
Li-fraumeni syndrome: an inherited family trait carrying an increased risk of cancer during childhood and early adulthood.
Lipid: fatty substances such as cholesterol and triglycerides. Lipids do not dissolve in water but are more soluble in organic solvents.

Lipodystrophy: fat metabolism disturbance.
Lipoma: a benign tumor containing fat.
Lipophilic: with an affinity for fat.
Lipoprotein: any complex of fat and protein.
Liposome: fatty or oily globule.
Lithotripsy: the operation of crushing a stone in the urinary bladder.
Liquifilm: thin liquid layer of coating.
Livedo: mottling.
Liver: a large abdominal organ that makes bile, changes food into energy, and filters alcohol and toxins from the blood.
Loading dose: initial dose.
Lochia: post-birth vaginal discharge.
Locomotor: movement-related.
Lordosis: abnormal increased forward curvature of the lumbar spine.
Lumbago: lower back pain.
Lumbar: the lower region of the back between the lowest ribs and the top of the pelvis.
Lumbar puncture: a procedure for removing spinal fluid from around the spinal cord using a fine needle in the lower part of the back.
Lumen: inside of a tube.
Lupus: see systemic lupus erythematosus (SLE).
Luxation: dislocation.
Lyme disease: is caused by a type of bacteria (spirochaete) which is carried by a tick found on wild animals which may cause a transient arthritis often treated with antibiotics. It was first described in the town of Lyme, USA.
Lymph: a transparent, slightly yellow fluid that carries lymphocytes to and from the lymph nodes and helps to collect foreign microbes. Lymph is derived from tissue fluids. The fluid passes through the lymphatic ducts and then enters the bloodstream.
Lymph nodes or glands: small structures found throughout the body, e.g. Neck, groin, armpits, abdomen, which contain both mature and immature lymphocytes.
Lymphadenopathy: lymph node swelling.
Lymphangitis: lymphatic vessel inflammation.
Lymphatic system: this consists of the spleen, lymph nodes and areas of lymphoid tissue such as the tonsils. It plays a major part of the body's immune response.
Lymphocyte: a type of white blood cell, includingB-cells and T-cells.
Lymphoid: referring to the lymphatic system including lymphocytes and lymph nodes.
Lymphokine: a substance produced by lymphocytes, a particular kind of white blood cell, with effects on other cells in the immune system. See also cytokine;interleukin.
Lymphoma: a cancer which originates in lymphoid tissue, including the lymph glands, liver, spleen, bowel and bone marrow. The disease results from the uncontrolled production of lymphocytes. The general term includes about a dozen different forms of the disease but there are two main categories: hodgkin's disease and non-hodgkin's lymphoma.
Lymphoproliferation: an increase in the production of lymphocytes. This may occur as a normal response to infection.
Lyophilisate: freeze.
Lysis: the splitting and dissolution of cellular or viral material by chemical action.
Lytic: cell destruction-related.

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