Destruction of Red Blood Cells

Red blood cells are quite elastic and flexible, and they readily bend as they pass through small blood vessels. With age, however, these cells become more fragile, and they are frequently damaged simply by passing through capillaries, particularly those in active muscles.

Damaged or worn red blood cells rupture as they pass through the spleen or liver. In these organs, macrophages (see chapter 5, p. 151) phagocytize and destroy damaged red blood cells and their contents. Hemoglobin molecules liberated from the red blood cells break down into their four component polypeptide "globin" chains, each surrounding a heme group. Heme further decomposes into iron and a greenish pigment called biliverdin. The iron, combined with a protein called transferrin, may be carried by the blood to the hematopoietic (red blood cell-forming) tissue in the red bone marrow and reused in synthesizing new hemoglobin. About 80% of the iron is stored in the liver cells in

Polypeptide chain (ß2)

Polypeptide chain (ß2)

Destruction Red Blood Cells

Iron-containing heme groups

Polypeptide chain (a2) Polypeptide chain (a.,) (a) Hemoglobin molecule

Iron-containing heme groups

Polypeptide chain (a2) Polypeptide chain (a.,) (a) Hemoglobin molecule

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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