Antibody - A modified type of serum globulin synthesized by plasma cells (activated B lymphocytes) in response to antigenic stimulus. By virtue of specific combining sites, each antibody reacts with only one antigen.
Anucleate - Having no nucleus.
Azurophilic granules - Reddish-purple granules (lysosomes) that may be visible in lymphocytes, particularly large lymphocytes. These are also known as primary granules or nonspecific granules.
Basophilic granules - Specific granules present in the cytoplasm of basophils. These granules are large and stain purple-black due to their strong affinity for basic stain.
B-cell - Bone marrow derived lymphocytes that produce humoral antibodies.
Biconcave - Having two concave surfaces.
Cellular Immunity - The capacity of a small proportion of lymphoid population to exhibit response to a specific antigen.
Chromomere - The centrally located granular portion of the platelet.
Clone - A population of cells descended from a single cell.
Delayed Hypersensitivity (part of cellular immunity) - It develops slowly over 24-72 hours after an antigenic stimulus. It consists of an accumulation of cells around small vessels and/or nerves. Example: Tuberculin skin test reaction.
Diapedesis - The passage of blood cells through blood vessel walls such as capillaries, usually in response to inflammation/infection.
Digestive Enzyme - A substance that catalyzes or accelerates the process of digestion.
Eosinophilic Granules - Specific granules present in the cytoplasm of eosinophils. These granules are large, refractile spheres that stain reddish-orange due to their strong affinity for acid stain.
Erythrocyte (red blood cell, RBC) - One of the elements found in peripheral blood. Typically the mature form is a non-nucleated, circular, biconcave disk adapted to transport respiratory gases.
Fixed Macrophage - A phagocyte that is non-motile.
Free Macrophage - An ameboid phagocyte present at the site of inflammation.
Graft Rejection - Cellular or humoral (antibody) response to a transplanted tissue resulting in inflammation and eventual death of the tissue.
Graft-vs.-Host Reaction - A complication that occurs when immune tissue is transplanted into a host resulting in the transplanted tissue mounting an immune response against the host’s tissues.
Granulocyte - A leukocyte that contains granules in its cytoplasm, i.e., neutrophilic, eosinophilic, or basophilic granules.
Half-life - The time it takes for half of the cells circulating at a given time to leave the blood for the tissues.
Hemocyte - Any blood cell or formed element of the blood.
Hemostasis - A mechanism of the vascular system to arrest an escape of blood. It involves an interaction between blood vessels, platelets, and coagulation.
Heparin - A mucopolysaccharide acid that, when present in sufficient amounts, functions as an anticoagulant by inhibiting thrombin.
Histamine - A powerful dilator of capillaries and a stimulator of gastric secretions.
Humoral Immunity - Acquired immunity produced after response to an antigenic stimulus in which B cells produce circulating antibodies.
Hyalomere - The clear, blue non-granular zone surrounding the chromomere of a platelet.
Immune Response - The interaction of a cell and an antigen that results in a proliferation of the cell and a capacity to produce antibodies or cellular-induced death of the antigen.
Isotonic Fluid - A fluid whose elements have an equal osmotic pressure.
Leukocyte (white blood cell, WBC) - One of the formed elements of the blood; involved primarily with the body's defense.
Lysosome - A membrane-bound organelle in a cell's cytoplasm capable of degrading or breaking down foreign substances.
Megakaryocyte - A giant cell of the bone marrow from which platelets are derived.
Mononuclear - A cell having a single nucleus.
