Blood - Hematology Review (Chapter 14)

Vocabulary flashcards covering concepts from the Blood chapter notes, including hematopoiesis, blood cells, plasma, coagulation, and blood groups.

Hematopoiesis

The formation of blood cellular components from hematopoietic stem cells in bone marrow.

Hematopoietic stem cell (hemocytoblast)

Multipotent stem cell in bone marrow that gives rise to all blood cell lineages.

Bone marrow

Site of hematopoiesis in adults; where hematopoietic stem cells reside.

Erythropoiesis

Production of red blood cells (RBCs).

Leukopoiesis

Production of white blood cells (WBCs).

Erythrocyte

Red blood cell; biconcave disk, ~7.5 μm, lacks nucleus/mitochondria and carries hemoglobin.

Hematocrit (Hct)

Percentage of blood volume occupied by packed RBCs; normal ~47% in men and ~42% in women.

Hemoglobin (Hb)

Oxygen-carrying protein in RBCs; four polypeptide chains with heme groups; ~280 million Hb molecules per RBC.

Heme

Iron-containing porphyrin ring in Hb that binds oxygen (iron Fe2+).

Heme iron

Iron from heme sources (e.g., meat); about 30% absorbed.

Non-heme iron

Iron from plant sources; absorption ~2–10% and aided by vitamin C and meat co-ingestion.

Intrinsic factor

Glycoprotein required for vitamin B12 absorption in the small intestine.

Vitamin B12

Vitamin essential for DNA synthesis in hematopoiesis; absorption requires intrinsic factor.

Folic acid (folate)

B vitamin required for DNA synthesis in RBC production.

Ferritin

Protein that stores iron in liver and reticuloendothelial system.

Erythropoietin (EPO)

Kidney-produced hormone that stimulates RBC production in response to hypoxia.

Reticulocyte

Immature RBC released from bone marrow; indicates RBC production.

Oxyhemoglobin

Hemoglobin bound to oxygen.

Deoxyhemoglobin

Hemoglobin without bound oxygen.

RBC life span

Red blood cells circulate ~120 days before destruction.

Spleen and liver macrophages

Phagocytose worn RBCs as part of RBC destruction and recycling.

Hemolysis

Destruction of red blood cells, typically by macrophages in spleen/liver.

Bilirubin

Pigment formed from heme breakdown; bilirubin excreted in bile.

Biliverdin

Green heme breakdown product that is converted to bilirubin.

Bile pigments

Pigments (including bilirubin) excreted in bile during RBC destruction.

Platelet (thrombocyte)

Cell fragment from megakaryocytes; essential for hemostasis; 130,000–360,000/μL.

Thrombopoietin

Hormone that stimulates megakaryocytes to produce platelets.

Platelet plug

Initial hemostatic platelet aggregation that forms a temporary seal.

Plasma

Liquid portion of blood; ~55% of blood; mostly water with proteins and electrolytes.

Albumin

Plasma protein that helps maintain colloid osmotic pressure; produced by liver.

Globulin

Plasma proteins including alpha and beta transport lipids; gamma globulins are antibodies.

Fibrinogen

Plasma protein that is converted to fibrin during blood coagulation.

Fibrin

Insoluble protein forming a mesh that stabilizes a blood clot.

Thrombin

Enzyme that converts fibrinogen to fibrin; central to coagulation.

Prothrombin activator

Complex that converts prothrombin to thrombin in the coagulation cascade.

Extrinsic clotting mechanism

Coagulation triggered by tissue factor (thromboplastin) from damaged tissue.

Intrinsic clotting mechanism

Coagulation triggered by contact with a foreign surface; involves Hageman factor XII.

Hemostasis

Process that stops bleeding: vascular spasm, platelet plug, and coagulation cascade.

Vascular spasm

Constriction of damaged blood vessels to reduce blood loss.

Prostacyclin

Vascular prostaglandin that inhibits platelet aggregation and promotes vasodilation.

Antithrombin

Inhibits thrombin to prevent excessive clotting.

Heparin

Anticoagulant that prevents clot formation; secreted by basophils/mast cells.

Agglutination

Clumping of red blood cells due to antigen–antibody interaction.

Antigen

Foreign substance (usually a protein) that elicits an antibody response.

Antibody (immunoglobulin)

Y-shaped protein produced by B cells that binds specific antigens.

ABO blood group

System based on A and B antigens on RBCs; antibodies in plasma determine compatibility.

Type A blood

RBCs carry A antigens; plasma contains anti-B antibodies.

Type B blood

RBCs carry B antigens; plasma contains anti-A antibodies.

Type AB blood

RBCs carry A and B antigens; plasma contains neither anti-A nor anti-B antibodies.

Type O blood

RBCs lack A and B antigens; plasma contains both anti-A and anti-B antibodies.

Rh factor (D antigen)

Rh positive means presence of D antigen; Rh negative means absence; important for transfusion compatibility.

Bombay phenotype (h/h)

Rare phenotype lacking H antigen; cannot form A or B antigens; has unique transfusion compatibility.

Sickle cell anemia

Genetic mutation causing deformed RBCs (sickle shape) and vascular occlusion; originated in West Africa.

WBC (leukocyte)

Cells that defend against disease; include neutrophils, eosinophils, basophils, monocytes, lymphocytes.

Neutrophil

Most abundant WBC; multilobed nucleus; first responders to bacterial infections; phagocytic.

Eosinophil

WBC with red granules; defends against parasites and mediates allergic reactions.

Basophil

WBC with blue granules; releases histamine and heparin during inflammation.

Monocyte

Largest WBC; becomes macrophage; phagocytizes bacteria and debris.

Lymphocyte

WBC involved in immunity; includes T cells, B cells, and NK cells.

Natural killer (NK) cell

Lymphocyte that targets virally infected cells and tumor cells; part of innate immunity.

Diapedesis

Process of leukocytes squeezing through capillary walls into tissue.

Positive chemotaxis

Movement of leukocytes toward damaged tissue in response to chemical signals.

Differential WBC count

Percentages of different leukocyte types in blood; diagnostic for diseases.

Red blood cell count (RBC count)

Number of RBCs per microliter of blood; normal ranges vary by sex and age.

Oxygen-carrying capacity

Ability of blood to transport O2, determined by RBC count and Hb content.

Diapedesis

Leukocytes move out of vessels to reach sites of tissue damage.

Hemocytoblast

Synonym for hematopoietic stem cell (HSC), origin of all blood cells.

Plasma electrolytes

Essential ions in plasma (Na+, K+, Ca2+, Mg2+, Cl−, bicarbonate, phosphate, sulfate).

Gibbs-Donnan effect

Electrochemical phenomenon affecting ion distribution across a semipermeable membrane due to impermeant plasma proteins.

Crossmatch (agglutination test)

Laboratory test to ensure donor and recipient blood compatibility by checking for agglutination.