22 X Glossary

Agranular leukocytes: White blood cells with few or no visible granules, including monocytes and lymphocytes. (Chapter 10.4)

Albumin: The most abundant plasma protein, made by the liver. It helps transport fatty acids and steroid hormones in the blood and maintains fluid balance. (Chapter 10.4)

Anemia: A general condition characterized by a deficient number of red blood cells (RBCs) or low hemoglobin levels. (Chapter 10.8)

Antibodies (Ab): Also called immunoglobulins, these are proteins that recognize and bind to specific antigens to help defend the body against pathogens. (Chapter 10.4)

Anticoagulant: Any substance that prevents coagulation. (Chapter 10.5)

Antigens: Substances that may trigger a defensive response from leukocytes of the immune system if the body does not recognize the antigen as belonging to “self.” (Chapter 10.7)

Aspirin: A medication that effectively inhibits the clumping (aggregation) of platelets and is classified as an antiplatelet drug. (Chapter 10.5)

B lymphocytes (B cells): White blood cells that defend the body against specific pathogens. A form of B cells called plasma cells produces antibodies. (Chapter 10.5)

Basophils: The least common leukocytes, typically making up less than one percent of the total leukocyte count. (Chapter 10.5)

Blood type A: A blood type classification for individuals whose erythrocytes (red blood cells) have A antigens on their surface. (Chapter 10.7)

Blood type AB: A blood type classification for individuals whose erythrocytes (red blood cells) have both A and B antigens on their surfaces. (Chapter 10.7)

Blood type B: A blood type classification for individuals whose erythrocytes (red blood cells) have B antigens on their surface. (Chapter 10.7)

Blood type O: A blood type classification for individuals whose red blood cells lack both A and B antigens. (Chapter 10.7)

Buffers: Substances in the blood, such as proteins and other molecules, that help maintain a stable pH in body tissues by neutralizing excess acids or bases. (Chapter 10.2)

Buffy coat: A thin, light-colored layer in a blood sample that contains white blood cells and platelets, usually less than 1% of the total blood volume. (Chapter 10.4)

Cardiovascular System: The body system made up of the heart and blood vessels that circulates blood to deliver oxygen and nutrients and remove waste products.  (Chapter 10.1)

Clinical laboratory technologists: Professionals with a bachelor’s degree and certification who perform a wide variety of tests on body fluids, including blood. (Chapter 10.9)

Coagulation: The process of blood clotting. (Chapter 10.5)

Colony-stimulating factors (CSF): Glycoproteins that stimulate the production and differentiation of white blood cells. Often used in patients receiving chemotherapy or bone marrow transplants to prevent low white blood cell counts. (Chapter 10.6)

Embolism: A condition that occurs when an embolus travels through the bloodstream and blocks a blood vessel supplying a major organ.

Embolus: A portion of a thrombus that breaks free from the vessel wall and enters the circulation. (Chapter 10.8)

Eosinophils: White blood cells that make up about 2–4% of all leukocytes. (Chapter 10.4)

Erythroblastosis fetalis: A condition that occurs when an Rh− mother has developed antibodies against Rh+ red blood cells, which cross the placenta and destroy the red blood cells of her Rh+ fetus. (Chapter 10.7)

Erythrocytes: Also called red blood cells (RBCs); cells that carry oxygen from the lungs to the tissues and remove carbon dioxide. (Chapter 10.2)

Erythropoiesis: The production of red blood cells (erythrocytes), stimulated by the hormone erythropoietin from the kidneys, occurring in red bone marrow at over 2 million cells per second. (Chapter 10.4)

Erythropoietin (EPO): A hormone made by the kidneys in response to low oxygen levels that prompts the production of erythrocytes. (Chapter 10.6)

Fibrin: An insoluble filamentous protein made from the plasma protein fibrinogen. (Chapter 10.5)

Fibrinogen: A plasma protein produced by the liver that is essential for blood clotting, making up about 7% of plasma proteins. (Chapter 10.4)

Fibrinolysis: The gradual breakdown of a blood clot. (Chapter 10.5)

Formed elements: The solid components of blood, which include erythrocytes (RBCs), leukocytes (WBCs), and thrombocytes (platelets). (Chapter 10.2)

Globulins: The second most common type of plasma protein, making up about 38% of the total plasma protein volume. (Chapter 10.4)

Granular leukocytes: White blood cells with many granules in their cytoplasm, including neutrophils, eosinophils, and basophils. (Chapter 10.4)

Hematocrit: A blood test that measures the percentage of erythrocytes (RBCs) in a blood sample. (Chapter 10.4)

Hematology: The study of blood cells (erythrocytes, leukocytes, and platelets) and the tissues that form them. (Chapter 10.1)

Hemoglobin: A large protein in red blood cells made of four chains, each holding an iron atom that binds oxygen for transport in the blood. (Chapter 10.4)

Hemolytic disease of the newborn (HDN): A condition that occurs when an Rh− mother has developed antibodies against Rh+ red blood cells, which cross the placenta and destroy the red blood cells of her Rh+ fetus. (Chapter 10.7)

Hemophilia: A genetic bleeding disorder in which blood does not clot properly, leading to hemorrhage from injuries, surgery, or spontaneous bleeding (bleeding with no known cause). (Chapter 10.8)

Hemopoiesis: The process by which blood cells are produced and replaced in the body. (Chapter 10.6)

Hemorrhage: Excessive or uncontrolled bleeding. (Chapter 10.5)

Hemostasis: The process that stops bleeding by forming a blood clot at the site of a damaged blood vessel. (Chapter 10.5)

Heparin: A medication that prevents blood clotting by inhibiting the formation of fibrin, used as an anticoagulant. (Chapter 10.5)

Hypoxemia: A condition where there are low levels of oxygen in the blood. (Chapter 10.4)

Immunoglobulins (Ig): Also called antibodies, these are proteins made by B cells that help the immune system recognize and fight antigens like bacteria and viruses. (Chapter 10.4)

Leukemia: A blood cancer characterized by an excessive number of leukocytes (white blood cells). (Chapter 10.8)

Leukocytes: Also called white blood cells (WBCs); cells that defend the body against infection and disease. (Chapter 10.2)

Leukocytosis: Excessive production of leukocytes (white blood cells), often resulting in nonfunctional WBCs and an increased risk of infection. (Chapter 10.8)

Leukopenia: A condition where too few leukocytes (white blood cells) are produced, increasing the risk of infection. (Chapter 10.8)

Lymphocytes: The second most common type of leukocyte, accounting for about 20–30 percent of all leukocytes, and are essential for the immune response. (Chapter 10.4)

Macrophage: A phagocytic cell in the bone marrow, liver, and spleen that removes worn-out red blood cells from circulation. (Chapter 10.4)

Medical laboratory scientists (MLS): Professionals with a bachelor’s degree and certification who perform a wide variety of tests on body fluids, including blood. (Chapter 10.9)

Medical laboratory technicians: Professionals who typically have an associate’s degree and may perform duties similar to those of clinical laboratory technologists. (Chapter 10.9)

Megakaryocyte: A large bone marrow cell that produces thrombocytes (platelets) by breaking off small fragments of its cytoplasm. (Chapter 10.4)

Memory cell: A variety of both B and T cells that forms after exposure to a pathogen to “remember” that pathogen and mount rapid responses during subsequent exposures. (Chapter 10.4)

Monocytes: Large agranular white blood cells that circulate in the blood and migrate into tissues, where they mature into macrophages to engulf and digest pathogens and debris. (Chapter 10.4)

Natural killer (NK) cells: White blood cells that recognize and destroy cells lacking “self” proteins or containing foreign or abnormal markers, providing a rapid response to infected or cancerous cells. (Chapter 10.4)

Neutrophils: The most common white blood cells, making up 50–70% of all leukocytes. (Chapter 10.4)

Phlebotomists: Health care professionals trained in the collection of blood samples. (Chapter 10.9)

Plasma: The liquid portion of blood that suspends the formed elements and transports nutrients, hormones, and waste. (Chapter 10.2)

Plasma proteins: Proteins that are unique to the plasma. (Chapter 10.4)

Plasmin: An active enzyme that gradually breaks down the fibrin mesh of a blood clot during the process of fibrinolysis. (Chapter 10.5)

Platelet plug: The process where platelets release chemicals that attract more platelets to help seal a damaged blood vessel. (Chapter 10.5)

Platelets: Another name for thrombocytes; help form blood clots to stop bleeding. (Chapter 10.2)

Polycythemia: An elevated red blood cell (RBC) count, often detected by an increased hematocrit (the percentage of red blood cells in the blood). (Chapter 10.8)

Polycythemia vera: A type of bone marrow disease that causes excessive production of immature red blood cells (RBCs), white blood cells (WBCs), and platelets. (Chapter 10.8)

Polymorphonuclear (PMN) neutrophils: Older neutrophils with a nucleus that has many lobes or shapes; often called “polys.” (Chapter 10.4)

Pulse Oximeter: A device placed on the fingertip that measures oxygen saturation by using red and infrared light to detect how much oxygen is in the blood. (Chapter 10.4)

Red blood cells (RBCs): Another name for erythrocytes; responsible for transporting oxygen and carbon dioxide. (Chapter 10.2)

Reticulocyte: An immature red blood cell that still contains some organelle remnants. (Chapter 10.4)

RhoGAM: Short for Rh immune globulin, this medication prevents an Rh− mother from developing antibodies against Rh+ red blood cells, helping to avoid hemolytic disease of the newborn. (Chapter 10.7)

Sensitization: The process by which an Rh− individual produces antibodies against the Rh antigen after exposure, such as through an Rh-incompatible transfusion or pregnancy with an Rh+ baby. (Chapter 10.7)

T lymphocytes (T cells): White blood cells that help coordinate immune responses and play a key role in specific immunity. (Chapter 10.4)

Tissue plasminogen activator (tPA): An enzyme that converts plasminogen into plasmin, which breaks down blood clots. It is used medically to treat strokes and heart attacks caused by clots. (Chapter 10.5)

Thrombocytes: Also called platelets; cell fragments involved in blood clotting to prevent bleeding. (Chapter 10.2)

Thrombocytopenia: An insufficient number of platelets in the blood, which can lead to excessive bleeding due to impaired clotting. (Chapter 10.8)

Thrombocytosis: A condition in which too many platelets are produced, potentially triggering unwanted blood clots that can be life-threatening. (Chapter 10.8)

Thrombophilia (hypercoagulation): A condition characterized by an increased tendency to form blood clots (thrombi). (Chapter 10.8)

Thrombopoietin: A hormone produced by the liver and kidneys that stimulates the development of megakaryocytes into platelets (thrombocytes). (Chapter 10.6)

Thrombosis: A potentially life-threatening condition caused by the formation of unwanted blood clots inside blood vessels. (Chapter 10.8)

Thrombus: A blood clot. (Chapter 10.8)

Universal donor: An individual with type O− blood who can donate blood to anyone because their red blood cells lack A, B, and Rh antigens, reducing the risk of an immune reaction. (Chapter 10.7)

Universal recipient: A patient with blood type AB+ who can receive red blood cells from any blood type because their blood contains all A, B, and Rh antigens, so they do not produce antibodies against these antigens. (Chapter 10.7)

Vascular spasm: A sudden constriction of the smooth muscle in the walls of a blood vessel that reduces blood flow to limit bleeding. (Chapter 10.5)

Venous stasis: A condition in which blood in the veins, especially in the legs, remains still or flows very slowly for long periods, increasing the risk of vessel damage. (Chapter 10.8)

Viscosity: A measure of a fluid’s thickness or resistance to flow. (Chapter 10.3)

Warfarin: An anticoagulant medication that prevents blood clot formation by interfering with vitamin K-dependent clotting factors. (Chapter 10.5)

White blood cells (WBCs): Another name for leukocytes; immune cells that help fight infections. (Chapter 10.2)