Glossary

Chronic: Diseases described as chronic last a long time, and involve very slow changes.

Essential: Disorders described as essential are not easily related to an outside cause.

Leukaemia: Any of a group of malignant diseases in which the bone marrow and other blood-forming organs produce increased numbers of white blood cells.

Megakaryocyte: A cell in the bone marrow that produces platelets.

Myeloid: Objects described as myeloid are either like, formed in, or relate in some way to the bone marrow.

Platelet: A cell fragment found in the blood, which helps blood to clot. Also sometimes known as a thrombocyte (throm-bo-site).

Spleen: A large red organ situated on the left side of the body below and behind the stomach. It is responsible for many important functions including the removal of old blood cells from the blood.

Thrombocythaemia: A disease in which there is an abnormal increase in megakaryocytes, leading to a high level of platelets.