Understanding Red Blood Cells: Shape, Size and Function

Understanding Red Blood Cells: Shape, Size and Function

Describe the morphology of red blood cells.
Answer:

Morphology of red blood cells:

• Morphology of red blood cells Shape:
  • It has disk-shaped and biconcave structure.
  • This structure has following advantages.
    1. Helps in easy and quick exchanges of gases.
    2. Allows easy folding of RBC on itself when it passes through capillaries.
    3. Allows consideration alteration in cell volume to withstand considerable changes in pressure.
    4. Provides large surface area for absorption or removal of different substances.
• Morphology of red blood cells Size:
  • Diameter -7.2 μ
  • thickness-2.2 μ at periphery, 1 μ at center.
  • Surface area – 120 sqm.
  • Volume-85-90 cu.m.
• Morphology of red blood cells Structure:
  • RBC is a non-nucleated cell.
  • DNA and mitochondria are absent.
  • Golgi apparatus is also absent.
  • Energy is produced from glycolytic process.
  • RBC contains cytoskeleton made up of actin and spectrin.
  • Both these proteins are anchored to transmembrane protein by ankyrin.
  • RBC cell membrane contains circular pores below which contractile protein spectrin lies.
  • Spectrin maintains shape and flexibility of RBC and contains antigen.
• Morphology of red blood cells Count:
  • At birth-6-7 million/μL
  • Adult: Male – 5-6 million/μL, female – 4.5-5.5 million/μL.
  • Life span 120 days after which it is destroyed by tissue macrhophage system.

Morphology of red blood cells Composition:

• Water 62.5%
• Hemoglobin – 35%
• Organic substances – 2.5%
• This includes sugar, lipids, protein and enzymes.