anemia The condition of not having enough hemoglobin in the blood to carry oxygen to
body cells.
antibodies Proteins that identify pathogens or other substances as being harmful; flow in
blood; can destroy pathogens by attaching to the cell membrane of the pathogen.
blood clotting The complex process by which blood forms solid clots.
blood transfusion The process of putting blood or blood products from one person into
the circulatory system of another person.
fibrin A tough protein that forms strands during the blood clotting process.
hemophilia A group of hereditary diseases that affect the body’s ability to control blood
clotting.
iron-deficiency anemia Occurs when the dietary intake or absorption of iron is less than
what is needed by the body. As a result, hemoglobin, which contains iron, cannot be
made.
leukemia Cancer of the blood or bone marrow; characterized by an abnormal production
of blood cells, usually white blood cells.
lymphoma Cancer of white blood cells calledlymphocytes.
plasma The golden-yellow liquid part of the blood.
platelets Fragments of larger cells that are important in blood clotting.
red blood cells (RBCs) Flattened disk-shaped cells that carry oxygen, the most com-
mon blood cell in the blood. Mature red blood cells do not have a nucleus.
rhesus (Rh) system The second most important blood group system in human blood
transfusion. A person either has, or does not have the Rh(D) antigen on the surface of
their RBCs; written asRh(D) positive(does have the RhD antigen) orRh(D) negative
(does not have the antigen).
sickle cell disease A blood disease that is caused by abnormally-shaped blood protein
hemoglobin.