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Fate of RBC

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erythrocyte lifespan

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red blood cell lifespan removal spleen hemoglobin bilirubin physiology

Fate of red blood cells (RBCs)

  • Life span: RBCs circulate for about 120 days.
  • As they age, they lose ATP and membrane flexibility, becoming less deformable.
  • Old or damaged RBCs are trapped and phagocytosed mainly by macrophages in the spleen, and also in the liver and bone marrow.

Fate of hemoglobin

ComponentFate
GlobinBroken into amino acids and reused for protein synthesis.
Heme iron (Fe)Removed, carried by transferrin, stored as ferritin/hemosiderin, and reused in new hemoglobin production.
Porphyrin ringConverted to biliverdin, then unconjugated bilirubin.

Fate of bilirubin

  1. Unconjugated bilirubin binds albumin in blood and travels to the liver.
  2. Liver conjugates it with glucuronic acid.
  3. Conjugated bilirubin is excreted in bile into the intestine.
  4. Intestinal bacteria convert it to urobilinogen:
    • Most becomes stercobilin and is excreted in feces, giving stool its brown color.
    • Some is reabsorbed and re-excreted by the liver.
    • A small amount reaches the kidneys and is excreted as urobilin, giving urine its yellow color.
Thus, RBC destruction conserves iron and amino acids, while the heme pigment is ultimately eliminated through bile and urine. The normal RBC lifespan is approximately 120 days, with macrophage-mediated clearance in spleen and liver. NCBI overview

Is this from giton

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Not directly from Guyton and Hall. The explanation was synthesized from standard physiology sources and medical-library material, but it is consistent with the “Destruction of Hemoglobin” topic taught in Guyton and Hall Textbook of Medical Physiology.
For exam-style Guyton wording, remember:
RBC lifespan 120 days → macrophages in spleen/liver/bone marrow destroy RBCs → globin to amino acids, iron recycled, porphyrin ring to bilirubin → bile → intestine → stercobilin in feces and urobilin in urine.

Give me a proper written or viva answer from guyton

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erythrocyte clearance macrophage

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Guyton Hall destruction of hemoglobin red blood cells 120 days macrophages

Fate of RBCs / Destruction of Hemoglobin

Written answer - Guyton style

Red blood cells normally circulate for an average of 120 days. As they grow older, their metabolic activity gradually decreases because mature RBCs have no nucleus, mitochondria, or endoplasmic reticulum. They become increasingly fragile and are unable to withstand repeated passage through narrow capillaries.
Old RBCs rupture or are phagocytosed by the macrophages of the reticuloendothelial system, particularly in the spleen, and also in the liver (Kupffer cells) and bone marrow.
After phagocytosis, hemoglobin is released from the RBC and is broken down as follows:
  1. Globin portion
    Globin is split into its constituent amino acids, which re-enter the body amino-acid pool and are reused for protein synthesis.
  2. Iron
    Iron is removed from heme and released into the blood. It binds to transferrin and is transported:
    • to the bone marrow for synthesis of new hemoglobin, or
    • to the liver and other tissues for storage as ferritin.
  3. Porphyrin ring of heme
    The porphyrin portion is converted first into biliverdin and then into bilirubin. Bilirubin is carried in blood to the liver, where it is excreted in the bile into the intestine. In the intestine, it is converted into urobilinogen. Most is ultimately excreted in feces as stercobilin, while a small amount is excreted in urine as urobilin.
Thus, the amino acids and iron of hemoglobin are conserved and reused, whereas the porphyrin portion is converted to bilirubin and eliminated through bile.

Short viva answer

“Sir/Ma’am, the normal life span of an RBC is about 120 days. Old RBCs become fragile and are destroyed mainly by macrophages in the spleen, liver, and bone marrow. Hemoglobin is split into heme and globin. Globin is converted to amino acids. Iron is transported by transferrin to bone marrow for reuse or stored as ferritin. The porphyrin part of heme is converted to biliverdin and then bilirubin, which is excreted through bile and finally leaves mainly as stercobilin in feces and a small amount as urobilin in urine.”
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