Regulation of Red Blood Cells

Key Concepts

• Regulation importance: Impacts blood viscosity and heart workload.
• Red Blood Cell (RBC) Count: Balance between production and destruction crucial.

Red Blood Cell Production

• Hypoxia: Low oxygen triggers RBC production.
• Kidneys Role: Detect lower oxygen, use Hypoxia Inducible Factor 1 (HIF1).
• Erythropoietin (EPO): Gene activated by HIF1, hormone stimulates RBC production in bone marrow.

RBC Production Process

• EPO Secretion: Not stored, produced as needed.
• Target Cells in Bone Marrow: Hematopoietic stem cells and intermediates.
• Immature RBCs (Reticulocytes): Spherical shape, contain nuclear fragments.
  • Mature into biconcave shape within 24-48 hours.
• Role of Testosterone: Enhances EPO release, higher RBC count in males.

RBC Destruction

• Lifespan: Approximately 120 days.
• Spleen Role: Breaks down old RBCs, recycles components.
  • Transferrin: Transports iron in blood.
  • Ferritin: Stores iron in liver.
  • Bilirubin: Byproduct, high levels can cause jaundice.

Osmotic Stresses on RBCs

• Isotonic Solution: Maintains biconcave shape.
• Hypertonic Solution: Water exits cell, causes crenation.
• Hypotonic Solution: Water enters cell, causes spherical shape.

Erythropoiesis Disorders

• Polycythemia Vera: Excessive RBC production.
  • Primary Polycythemia Vera: Caused by bone marrow cancer.
  • Secondary Polycythemia Vera: Caused by hypoxia (e.g., high elevation).

Blood Doping

• Methods:
  • Re-injecting stored blood.
  • Injecting artificial EPO.
  • Training at high elevations.

Nutrients Needed for RBC Production

• Key nutrients: Carbohydrates, fats, amino acids, iron, vitamins (B9/folate, B12).
• Impact of Deficiencies:
  • B9 and B12 Deficiency: Larger, less efficient RBCs.
  • Iron Deficiency: Smaller RBCs, lower oxygen delivery.

Practical Tips

• Diet: Include iron-rich, B9, and B12-rich foods.