Red Blood Cells & Blood Typing – Key Vocabulary

These flashcards cover essential vocabulary from the lecture on erythrocyte structure, hemoglobin function, erythropoiesis, red blood cell recycling, bile production, and ABO blood typing.

Red Blood Cell (Erythrocyte)

Small, anucleate blood cell packed with hemoglobin whose primary job is to transport oxygen and carbon dioxide.

Biconcave Disc

Flattened, indented shape of an erythrocyte that shortens diffusion distance and increases flexibility in narrow vessels.

Hemoglobin

Large, four-subunit protein in RBCs composed of globin chains and heme groups that binds and carries O₂ and CO₂.

Globin

Protein portion of hemoglobin made of two α and two β chains that help form the functional ‘super-protein.’

Heme

Iron-containing pigment ring within each globin subunit; iron in the center reversibly binds one O₂ molecule.

Oxyhemoglobin

Bright-red form of hemoglobin with oxygen bound; typical of arterial blood.

Deoxyhemoglobin

Hemoglobin that has released its oxygen; appears darker and is found mainly in venous blood.

Oxygen Affinity

Strength of hemoglobin’s attachment to oxygen; high in the lungs, lower in tissues to allow release.

Erythropoiesis

Process of producing new red blood cells in red bone marrow.

Erythropoietin (EPO)

Kidney-derived hormone that stimulates erythropoiesis in response to low blood oxygen.

Hypoxemia

Abnormally low oxygen level in arterial blood that triggers EPO release.

Red Bone Marrow

Hematopoietic tissue in certain bones where all blood cells, including erythrocytes, are formed.

Macrophage

Large phagocytic cell in spleen, liver, and marrow that engulfs and breaks down aged erythrocytes.

Phagocytosis

Cellular ‘eating’ process in which a phagocyte engulfs particles or cells into a digestive vesicle.

Lysosome

Organelle containing degradative enzymes that fuses with phagosomes to digest captured material.

Transferrin

Plasma protein that transports iron (Fe) through the bloodstream.

Ferritin

Iron-storage protein complex in the liver and other tissues; releases iron when needed for hemoglobin synthesis.

Biliverdin

Green pigment produced from heme breakdown that is quickly reduced to bilirubin.

Bilirubin

Yellow pigment from heme catabolism that the liver converts into bile; accumulation causes jaundice.

Bile

Detergent-like fluid made in the liver (stored in gallbladder) that emulsifies dietary lipids in the small intestine.

Gallbladder

Small sac under the liver that stores and concentrates bile until fatty food enters the intestine.

Jaundice

Yellow discoloration of skin/eyes caused by excess circulating bilirubin due to liver or hemolytic issues.

120-Day Lifespan

Average functional life of an erythrocyte before removal by macrophages.

Antigen

Any molecule—often on a cell surface—that can trigger an immune response; on RBCs they define ABO type.

Antibody

Y-shaped protein produced by B-cells that binds specific antigens and helps eliminate them.

ABO Blood Group

Major blood-typing system based on presence of A and/or B antigens on erythrocytes.

Type A Blood

Has A antigens on RBCs and pre-formed anti-B antibodies in plasma.

Type B Blood

Has B antigens on RBCs and pre-formed anti-A antibodies in plasma.

Type AB Blood

Has both A and B antigens and no anti-A or anti-B antibodies; accepts A, B, AB, or O blood of compatible Rh.

Type O Blood

Lacks A and B antigens and possesses both anti-A and anti-B antibodies; can donate to all ABO types with compatible Rh.

Phagocyte

General term for any cell (e.g., macrophage) capable of engulfing and digesting particles or cells.

Iron (Fe)

Trace metal at the center of each heme that reversibly binds oxygen; recycled via transferrin and ferritin.