Your blood is living tissue made up of liquid and solids. The liquid part, called plasma, is made of water, salts, and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells, and platelets.
Red blood cells deliver oxygen from your lungs to your tissues and organs. White blood cells fight infection and are part of your body's defense system. Platelets help blood to clot when you have a cut or wound. Bone marrow, the spongy material inside your bones, makes new blood cells. Blood cells constantly die and your body makes new ones. Red blood cells live about 120 days, platelets 6 days and white cells less than a day.
- Blood and Diversity (American Red Cross)
- Blood Type Game (American Red Cross)
- Biology of Blood (Merck & Co., Inc.)
- ClinicalTrials.gov: Blood Cells (National Institutes of Health)
Journal ArticlesReferences and abstracts from MEDLINE/PubMed (National Library of Medicine)
- Hematology Glossary (American Society of Hematology)
- Facts and Figures (America's Blood Centers)