Hematology: The branch of medicine that deals with the study of blood cells, blood
producing organs and the manner in which these cells and organs are affected in
Hematoma: Subcutaneous effusion of blood with resulting swelling, pain, and
discoloration, forming a tumorlike mass.
Hematopoietic (Hemopoietic): Blood forming.
Hemoglobin: The coloring matter of the red blood cells. A complex iron-bearing
pigment that carries oxygen and carbon dioxide.
Hemoglobinuria: The presence of free hemoglobin in the urine.
Hemogram: The blood picture.
Hemolysis: The dissolution or dissolving of the erythrocytes.
Hemolytic Anemia: That type of anemia characterized by excessive intra-vascular
destruction of red cells.
Hemophilia: A hereditary disease characterized by a prolonged coagulation time and
repeated hemorrhages, occurring only in males and transmitted only by females and
affected males. The cause is a deficiency in a plasma factor (antihemophilic globulin or
thromboplastinogen) resulting in a defect in thromboplastic activity.
Hemoptysis: The spitting of blood; coughing up blood.
Hemostasis: The checking of the flow of blood, especially from a vessel.
Hepatic: Originating from the liver.
Heterozygous: Derived from germ cells unlike in respect to one or more factors.
Hemeostasis: Stability in normal body states.
Homozygous: Derived from germ cells that are alike.
Howell-Jolly Bodies: Small basophilic particles sometimes found in erythrocytes,
remnants of nuclear material.
Hygroscopic: Readily taking up and retaining water.
Hyperplasia: An increase in cell formation.
Hypertonic: Greater than isotonic concentration.