[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Physiology](https://durgical.com/en/physiology/) › [Blood, hemostasis and basic immunity](https://durgical.com/en/physiology/#s-blood) › The red cell life cycle and the spleen [Physiology](https://durgical.com/en/physiology/) · [Blood, hemostasis and basic immunity](https://durgical.com/en/physiology/#s-blood) # The red cell life cycle and the spleen - Concept - Exam priority: medium A red cell lives about four months. Old, stiff cells are caught in the spleen, eaten, and their iron is reused; the rest becomes bilirubin. Updated 2026-11-01 Also called: Red cell destruction, Hemolysis, Splenic function **See it in 3D:** [Spleen](https://durgical.com/en/anatomy/spleen/) · [Liver](https://durgical.com/en/anatomy/liver/) · [Splenic artery](https://durgical.com/en/anatomy/splenic-artery/) ## Key points - Red cell energy: glycolysis for ATP (pyruvate kinase), the pentose phosphate pathway for NADPH (G6PD) to keep glutathione reduced, and the Rapoport–Luebering shunt for 2,3-BPG. - Extravascular hemolysis (spleen, liver): high unconjugated bilirubin, splenomegaly, no hemoglobinuria. - Intravascular hemolysis: free hemoglobin binds haptoglobin (low haptoglobin), hemoglobinuria, hemosiderinuria. - Heme → biliverdin → unconjugated bilirubin (on albumin) → conjugated in the liver; iron is recycled; globin becomes amino acids. - After splenectomy: Howell–Jolly bodies, target cells, thrombocytosis and a lifelong risk of severe infection by encapsulated bacteria. ## What it is Mature red cells have no nucleus or mitochondria, so they cannot repair themselves and run on glycolysis alone. After about 120 days they become stiff and are removed mainly by macrophages in the splenic red pulp. The spleen also filters blood for damaged cells, inclusions and encapsulated bacteria, and holds a reserve of platelets. ## Key facts - The cords of the red pulp force cells through slits only a few micrometres wide: rigid or coated cells are trapped. - 'Pitting' removes inclusions (Howell–Jolly, Heinz bodies) without destroying the cell; 'culling' removes whole cells. - The spleen holds about a third of the platelets; hypersplenism lowers all counts. - Oxidant stress (fava beans, some drugs, infection) in G6PD deficiency denatures hemoglobin into Heinz bodies → bite cells. ## Where the red cell is destroyed | Feature | Extravascular | Intravascular | | --- | --- | --- | | Site | Splenic and hepatic macrophages | Inside blood vessels | | [Typical causes](https://durgical.com/en/conditions/sickle-cell-disease/) | Spherocytosis, IgG-coated cells, sickle cells | ABO mismatch, complement (PNH), mechanical valves, malaria | | Haptoglobin | Normal or mildly low | Very low | | Urine | Dark from urobilinogen; no hemoglobin | Hemoglobinuria, later hemosiderinuria | ## Clinical notes - Sickle cell disease: repeated splenic infarcts cause 'autosplenectomy' in childhood, hence pneumococcal risk. - Splenic injury is the most common solid-organ injury in blunt abdominal trauma. - Plasmodium invades and ruptures red cells; in Colombia malaria (P. vivax and P. falciparum) is a common cause of hemolysis in endemic regions. ## Memory aid The spleen is the quality inspector at a narrow gate: soft cells pass, stiff or tagged cells are recycled. ## Test yourself Think of the answer, then tap the question to see it. ## Why is the red cell entirely dependent on glycolysis? It has no mitochondria, so it cannot use oxidative phosphorylation; ATP comes only from glycolysis, which is why pyruvate kinase deficiency causes hemolysis. ## Why does G6PD deficiency cause hemolysis only under oxidant stress? G6PD makes NADPH to regenerate reduced glutathione. Under normal conditions enough is made; with oxidants (infection, fava beans, some drugs) the cell cannot detoxify peroxide and hemoglobin denatures. ## Why is haptoglobin low in intravascular hemolysis? Free hemoglobin released in the plasma binds haptoglobin, and the complex is quickly cleared by the liver, using up haptoglobin. ## Why does a person without a spleen face a higher risk from encapsulated bacteria? The spleen filters blood-borne bacteria and makes IgM and opsonizing antibodies against capsular polysaccharides; without it, organisms like pneumococcus are cleared poorly. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/physiology/the-red-cell-life-cycle-and-the-spleen/) ## See it in 3D The structures of Durgical's 3D anatomy where it happens. - [Spleen](https://durgical.com/en/anatomy/spleen/) - [Liver](https://durgical.com/en/anatomy/liver/) - [Splenic artery](https://durgical.com/en/anatomy/splenic-artery/) ## Related topics - [Erythropoiesis and erythropoietin](https://durgical.com/en/physiology/erythropoiesis-and-erythropoietin/) - [Body iron balance](https://durgical.com/en/physiology/body-iron-balance/) - [Anemia physiology and compensation](https://durgical.com/en/physiology/anemia-physiology-and-compensation/) - [Bile and the enterohepatic circulation](https://durgical.com/en/physiology/bile-and-the-enterohepatic-circulation/) ## Related conditions - [Glucose-6-phosphate dehydrogenase (G6PD) deficiency](https://durgical.com/en/conditions/glucose-6-phosphate-dehydrogenase-deficiency/) - [Sickle cell disease](https://durgical.com/en/conditions/sickle-cell-disease/) - [Splenic injury](https://durgical.com/en/conditions/splenic-injury/) - [Pyruvate kinase deficiency](https://durgical.com/en/conditions/pyruvate-kinase-deficiency/) - [Neonatal jaundice](https://durgical.com/en/conditions/neonatal-jaundice/) - [Malaria](https://durgical.com/en/conditions/malaria/) ## In Biochemistry - [Heme breakdown and bilirubin](https://durgical.com/en/biochemistry/pathways/heme-breakdown-and-bilirubin/) - [Glucose-6-phosphate dehydrogenase (G6PD)](https://durgical.com/en/biochemistry/enzymes/glucose-6-phosphate-dehydrogenase/) - [Pyruvate kinase](https://durgical.com/en/biochemistry/enzymes/pyruvate-kinase/) - [Bilirubin](https://durgical.com/en/biochemistry/molecules/bilirubin/) - [Pentose phosphate pathway](https://durgical.com/en/biochemistry/pathways/pentose-phosphate-pathway/) - [Glutathione (GSH)](https://durgical.com/en/biochemistry/molecules/glutathione/) [← All of physiology](https://durgical.com/en/physiology/) Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given. Sources: [18.3 Erythrocytes](https://openstax.org/books/anatomy-and-physiology-2e/pages/18-3-erythrocytes) (OpenStax (Rice University), 2022); [Anatomy, Abdomen and Pelvis, Spleen](https://www.ncbi.nlm.nih.gov/books/NBK482235/) (StatPearls (NCBI Bookshelf), 2024); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 33). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/physiology/the-red-cell-life-cycle-and-the-spleen/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/physiology/the-red-cell-life-cycle-and-the-spleen/