McCance Chapter 28 Structure and Function of the Hematologic System

Hematocrit

Percentage of cells in blood volume

Bilirubin

Byproduct of heme metabolism secreted in bile salts

Biliverdin

Byproduct of heme metabolism, greenish pigment secreted in bile salts

Transferrin

Protein that transports iron

Ferritin

Protein that stores iron

Erythropoiesis

Production of red blood cells

Erythroblast

Immature red blood cell is derived from hemocytoblasts and synthesizes hemoglobin

Reticulocyte

Derived from an erythroblast, a cell differentiates nuclei shrink and are extruded by exocytosis, cell still has a remnant of endoplasmic reticulum, this stage exits the bone marrow

Erythropoietin

Hormone produced and released by the kidneys in response to prolonged hypoxia, stimulates red blood cell production in the bone marrow

Vitamin B12 (cobalamin)

Used to regenerate folate

Vitamin B9 (folic acid)

Required for DNA and RNA synthesis in rapidly dividing cells

Iron

Required for hemoglobin synthesis

Vitamin C (ascorbic acid)

Increases absorption of iron in the digestive tract

Granulocytes

Leukocyes that have membrane bound organelles that appear purple with Wright's stain

Neutrophils

Granulocyte, first to arrive at a site of infection and phagocytize bacteria, fungi and some viruses

Eosinophils

Granulocyte, mediates moderate allergic reactions and defends against parasitic worm infestations

Basophils

Granulocyte, migrate to damaged tissue and release histamine and heparin

Monocytes

Agranulocyte, largest blood cells, leave the bloodstream and become macrophages (phagocytize bacteria, dead cells and cellular debris), contain numerous lysosomes with digestive enzymes

Lymphocytes

Agranulocytes, B (produce antibodies that attack foreign cells or proteins) and T cells (attack microorganisms, tumor cells and transplanted cells)

Diapedesis

Leukocytes squeeze thru openings in capillaries and leave the bloodstream

Leukocytosis

Increase in whie blood cells

Leukopenia

Decrease in whie blood cells

Platelets (thrombocytes)

Cell fragments that are activated by exposed collagen in blood vessels, they form aggregates with fibrin and red blood cells (clot)

Megakaryoblasts

Immature megakaryocyte

Thrombopoeitin

Hormone that stimulated megakaryocytes to fragment and differentiate into platelets

Albumins

Plasma proteins that bind and transport free fatty acids, bilirubin, hormones and certain drug, major determinant of osmotic pressure in blood vessels

Alpha and beta globulins

Proteins synthesized in liver, transport lipids and fat soluble vitamins

Gamma globulins

Antibodies

Fibrinogen

Protein synthesized in the liver and involved in blood coagulation

Chylomicron

High concentration of triglycerides, transports dietary fats to adipose and muscle cells

Very low density lipoproteins

High concentration of triglycerides, transports triglycerides from liver to adipose tissue

Low density lipoproteins

High concentration of cholesterol (formed from VLDL that have given up their triglycerides), delivers cholesterol to cells

High density lipoproteins

High concentration of proteins, transports chylomicron remnants (they have given up their triglycerides) to the liver

Urea

Nitrogenous byproduct of protein catabolism

Uric acid

Nitrogenous byproduct of nucleic acid catabolism

Creatinine

Byproduct of creatine catabolism

Hemostasis

Stoppage of bleeding

Extrinsic clotting

Clotting cascade is triggered by release of biochemicals from broken blood vessels or damaged tissue

Thrombin

Catalyzes the formation of fibrin from fibrinogen

Intrinsic clotting

Clotting cascade is triggered when blood contacts foreign surfaces in absence of tissue damage

Plasmin

Digests fibrin

Embolus

Dislodged thrombus that is carried by the bloodstream

Infarction

Death of cells supplied by a vessel that is blocked by a thrombus or embolus

Atherosclerosis

Clot formation in an artery with accumulations of fatty deposits

Antithrombin

Binds to thrombin and inactivates it

Heparin

Highly sulfated glycosaminoglycan that is secreted by mast cells and basophils and acts as an anticoagulant

Rh antigens

Proteins on the surface of red blood cells, antibodies against these proteins agglutinate red blood cells that express the proteins

Erythroblastosis fetalis

During the second pregnancy with an Rh-positive child, the mothers anti-Rh antibodies can cross the placenta and attack the fetal RBCs