- Body fluids : Add brief definition or description
- Physiology : The study of the mechanical, physical, and biochemical functions of tissues and how they interact.
- Hematology : In broad terms, the study of the morphology, physiology, and pathology of the blood and blood-forming tissues; also a subspecialty of internal medicine dealing with the diseases of these tissues
- Blood cells : In blood, the cells suspended in plasma; the primary types being erythrocytes, leukocytes and platelets
- Complete blood count : A basic set of counts and ratios of various blood cells, which can be both individually and jointly valuable in medical diagnosis
- Erythrocyte : Blood cells that carry hemoglobin
- Erythrocyte indices : A set of three clinically useful parameters calculated from measurements of erythrocytes, usually reported with a complete blood count
- Reticulocyte : An immature erythrocyte (i.e., red blood cell), of which small numbers may be present in circulating blood; elevated percentages, or a lack of them when other factors are abnormal, suggest a disorder of erythropoiesis.
- Leukocyte : Colourless cells of the immune system which defend the body against both infectious disease and foreign materials, and grouped into neutrophils, eosinophils, basophils, lymphocytes, and monocytes.
- Basophil : A circulating leukocyte which, when sensitized to a specific antigen by means of an immunoglobulin E molecule bound to its surface, will release physiologically potent chemicals on recognizing that antigen
- Eosinophil : A leukocyte (white blood cell), the number of which rise in inflammatory disorders and parasitic infections
- Neutrophil : Leukocytes (white blood cells) whose primary role is in the cell-mediated immune system, where they destroy hostile substance by phagocytosis. They do release interleukin-12.
- Monocyte : Large, phagocytic mononuclear leukocytes produced in the vertebrate bone marrow and released into the blood; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles (Medical Subject Headings); they are the precursors of non-circulating macrophages
- Lymphocyte : Leukocyte originating in lymphoid tissues, fundamental to the immune system, regulating and participating in acquired immunity, with receptor molecules on its surface that bind to a specific antigen.
- Platelet : Cell fragments circulating in the blood.
- Plasma (biology) : The residual portion of blood that is left after removal of blood cells by centrifugation without prior coagulation; contains proteins, colloids, cytokines, electrolytes
- Blood gas analysis : Test which measures the amounts of oxygen and carbon dioxide in the blood, as well as the acidity (pH) of the blood.
- Coagulation : The process of the interaction of blood coagulation factors that results in an insoluble fibrin clot.
- Lymph : Add brief definition or description
- Hormone : A chemical director of biological activity that travels through some portion of the body as a messenger.
- Bone marrow : The soft tissue, inside the hollow cavities of bones, which produces blood cells
- Mast cell : Non-circulating, but leukocyte-like (especially basophil) associated with the inflammatory response, especially the release of histamine.
- Macrophage : A type of leukocyte (i.e., white blood cells) that is associated with chronic inflammatory response. It digests foreign cells using the mechanism of phagocytosis, and both circulates in the blood, but later attaches to tissue as a part of local immune response.
- Blood-brain barrier : Specialized non-fenestrated tightly-joined endothelial cells with tight junctions that form a transport barrier for certain substances between the cerebral capillaries and the brain tissue.