Blood, Lymph, and Immunity

Agranulocyte

White blood cells without visible granules in their cytoplasm includes lymphocytes and monocytes

Antibody

Proteins produced by plasma cells that specifically recognize and bind to foreign antigens

Anticoagulant

A substance that prevents blood from clotting

Antigen

Any substance that triggers an immune response and can be recognized by antibodies

B cell (B lymphocyte)

Lymphocyte involved in antibody production; develops and matures in the bone marrow and becomes activated in secondary lymphoid tissues such as the spleen and lymph nodes, where it can differentiate into antibody-producing plasma cells.

Basopenia

A decreased number of basophils in the blood

Basophil

A granulocyte with dark blue-purple granules that releases histamine and heparin during allergic reactions

Basophilia

An increased number of basophils in the blood

Chemotaxis

The movement of cells toward or away from chemical signals

Deoxyhemoglobin

Hemoglobin that has released its oxygen to tissues

Diapedesis

The process by which white blood cells squeeze through blood vessel walls to reach infected tissues

Edema

Abnormal accumulation of fluid in body tissues

Eosinopenia

A decreased number of eosinophils in the blood

Eosinophil

A granulocyte with red-pink granules that fights parasites and responds to allergies

Eosinophilia

An increased number of eosinophils in the blood

Erythrocyte

Red blood cells that carry oxygen throughout the body

Erythropoiesis

The production of red blood cells in bone marrow

Erythropoietin (EPO)

A hormone produced by kidneys that stimulates red blood cell production

Extravascular hemolysis

Destruction of red blood cells outside blood vessels, primarily in the spleen

Fibrin

Insoluble protein strands that form the mesh of a blood clot

Fibrinogen

Soluble plasma protein that converts to fibrin during clotting

Fibrinolysis

The breakdown and dissolution of fibrin in blood clots

Granulocyte

White blood cells with visible granules in their cytoplasm; includes neutrophils, eosinophils, and basophils

Granulopoiesis

The production of granulocytes in bone marrow

Gut associated lymph tissue

Lymphoid tissue in the intestinal walls that provides immune protection

Haptoglobin

A plasma protein that binds free hemoglobin in the blood

Hematocrit

The percentage of blood volume occupied by red blood cells, measured by automated analyzers

Hematopoiesis

The formation and development of all blood cells

Hemoglobin

The oxygen-carrying protein in red blood cells

Hemoglobinemia

The presence of free hemoglobin in plasma due to red blood cell destruction

Hemoglobinuria

The presence of hemoglobin in urine

Hemostasis

The process of stopping bleeding through clot

Hypoxia

Inadequate oxygen supply to tissues

Intravascular hemolysis

Destruction of red blood cells within blood vessels

Leukocyte

White blood cells that fight infection and provide immunity

Leukocytosis

An elevated white blood cell count

Leukopenia

A decreased white blood cell count

Leukopoiesis

The production of white blood cells in bone marrow

Lymph

Clear fluid containing white blood cells that circulates through lymphatic vessels

Lymphocyte

Small agranulocytes that provide specific immune responses

Lymphocytosis

An increased lymphocyte count in blood

Lymphopenia

A decreased lymphocyte count in blood

Lymphopoiesis

The production of lymphocytes

Macrophage

Large phagocytic cells that engulf pathogens and cellular debris

Mast cell

Tissue immune cells containing histamine granules that mediate allergic reactions

Megakaryocyte

Large bone marrow cells that break into platelets

Monocyte

Large agranulocytes in blood that differentiate into macrophages in tissues

Monocytopenia

A decreased monocyte count in blood

Monocytosis

An increased monocyte count in blood

Monopoiesis

The production of monocytes in bone marrow

Mononuclear phagocyte system (MPS)

Network of phagocytic cells including monocytes and macrophages throughout the body

Natural killer cell (NK cell)

Lymphocytes that attack virus-infected and cancerous cells without prior sensitization

Neutropenia

A decreased neutrophil count in blood

Neutrophil

The most abundant granulocyte that provides first-line defense against infection

Neutrophilia

An increased neutrophil count in blood

Opsonin

Antibodies or complement proteins that coat pathogens to enhance phagocytosis

Opsonization

The process of coating pathogens with opsonins to facilitate phagocytosis

Oxyhemoglobin

Hemoglobin bound to oxygen

Packed cell volume (PCV)

The percentage of blood volume occupied by red blood cells after centrifugation

Peripheral blood

Blood circulating in blood vessels throughout the body

Petechiae

Tiny red or purple spots on skin or mucous membranes from bleeding

Phagocytosis

The process by which cells engulf and digest pathogens and debris

Phagosome

A vesicle formed around material engulfed by phagocytosis

Plasma

The clear, yellowish liquid portion of blood containing proteins, electrolytes, clotting factors, and other dissolved substances

Plasma cell

Differentiated B cells that produce large quantities of antibodies

Platelet

Small cell fragments that initiate blood clotting

Pluripotential stem cell (PPSC)

Bone marrow cells capable of developing into any type of blood cell

Polycythemia

An abnormally high red blood cell count

Polymorphonuclear

Cells with irregularly shaped, multi-lobed nuclei; refers to neutrophils

Postprandial lipemia

Cloudy, fatty appearance of blood after eating

Red bone marrow

Active blood-forming tissue in bones

Red pulp

The portion of the spleen that filters blood and removes old red blood cells

Senescence

The process of cellular aging and deterioration

Serum

The clear liquid that remains after blood clots, plasma without clotting factors

Thrombocyte

Platelets; cell fragments that initiate blood clotting

Thrombocytopenia

A decreased platelet count in blood

Thrombocytosis

An increased platelet count in blood

Thrombopoiesis

The production of platelets from megakaryocytes

Thymus

Lymphoid organ where T cells mature

T cell (T lymphocyte)

Lymphocytes that mature in the thymus and coordinate immune responses

Vacuole

Fluid-filled spaces within cells

White pulp

Lymphoid tissue within the spleen that produces lymphocytes

Whole blood

Blood containing all cellular components and plasma

Yellow bone marrow

Inactive, fatty bone marrow that can convert to red marrow when needed