Iron & Copper in Erythrocyte Production

Iron's Role in Erythrocyte Production

• Iron is a trace mineral present in each heme group of a hemoglobin molecule.
• The body absorbs less than 20% of consumed iron.
• Heme iron, found in animal foods, is absorbed more efficiently than non-heme iron from plants.
• Absorbed iron contributes to the body's total iron pool.
• Bone marrow, liver, and spleen store iron in ferritin and hemosiderin.
• Ferroportin transports iron across intestinal cell membranes and from storage into tissue fluid for blood transport.
• EPO stimulates erythrocyte production, which causes iron to be released from storage sites.
• Iron then binds to transferrin, and is carried to the red marrow where it can attach to erythrocyte precursors.

Copper's Role in Erythrocyte Production

• Copper is a trace mineral and a component of hephaestin and ceruloplasmin.
• Without copper, hemoglobin production would be inadequate.
• Hephaestin, located in intestinal villi, enables iron absorption by intestinal cells.
• Ceruloplasmin transports copper.
• Both hephaestin and ceruloplasmin enable the oxidation of iron from Fe2+ to Fe3+, so that it can bind to transferrin.
• Copper deficiency reduces iron transport for heme synthesis.
• Copper deficiency can lead to iron accumulation in tissues and eventual organ damage.

Zinc's Role in Erythrocyte Production

• Zinc is a trace mineral and a co-enzyme that facilitates the synthesis of the heme portion of hemoglobin.

B Vitamins' Role in Erythrocyte Production

• Folate and vitamin B12 are B vitamins that act as co-enzymes to facilitate DNA synthesis.
• Folate and vitamin B12 are critical for the synthesis of new cells, including erythrocytes.

Erythrocyte Life Cycle Overview

• Erythrocytes circulate for up to 120 days.
• Macrophages, myeloid phagocytic cells in the bone marrow, liver, and spleen, remove worn-out erythrocytes.
• Hemoglobin components from degraded erythrocytes are processed further.

Globin Breakdown

• Globin, the protein portion of hemoglobin, breaks down into amino acids.
• These amino acids is can be reused in the bone marrow to produce new erythrocytes.
• Hemoglobin that is not phagocytized breaks down in the circulation, releasing alpha and beta chains.
• The chains are then removed from circulation by the kidneys.

Iron Recycling

• Iron from the heme portion of hemoglobin is stored in the liver or spleen as ferritin or hemosiderin.
• The iron can also be carried by transferrin in the bloodstream to the red bone marrow.
• The iron is then recycled into new erythrocytes.

Non-Iron Heme Portion Breakdown

• The non-iron heme portion degrades into biliverdin, a green pigment, and then into bilirubin, a yellow pigment.
• Bilirubin binds to albumin and travels to the liver.
• The liver uses bilirubin to manufacture bile, which emulsifies dietary fats in the intestines.
• In the large intestine, bacteria convert bilirubin into urobilinogen and then into stercobilin.
• Stercobilin is then eliminated from the body in the feces.
• Broad-spectrum antibiotics can affect the bacteria involved in this process and may alter the color of feces.
• Kidneys also remove bilirubin and related byproducts like urobilins from circulation and secrete them into the urine.