Erythrocyte Development and Membrane

Which characteristic is unique to mature erythrocytes compared to the reticulocyte?

What is the primary composition in the cytoplasm of a reticulocyte?

What are Howell-Jolly bodies?

What is the average life span of a mature erythrocyte?

Which protein in RBC membranes primarily functions as a glucose transporter?

What indicates the last stage of hemoglobin synthesis in RBC development?

How much of a mature erythrocyte's diameter does the central pallor occupy?

Which statement about reticulocytes is correct regarding their lifespan?

Erythrocyte Development

Pyrenocyte: Enveloped, extruded nucleus engulfed by bone marrow macrophages. Small fragments of the nucleus are left behind, called Howell-Jolly bodies.
Reticulocyte: 7-10 μm size, no nucleus or nucleolus. Cytoplasm is predominantly hemoglobin, but with a bluish tinge due to residual ribosomes and RNA. Later stages are salmon pink. Last stage of hemoglobin synthesis. Spends 2-3 days in bone marrow and 1 day in peripheral blood before becoming a mature RBC. Irregular shape visible in electron micrographs.
Mature Erythrocyte: 6-8 μm size, no nucleus, nucleolus, or mitochondria. Salmon pink cytoplasm with a central pallor occupying 1/3 of the cell's diameter. Biconcave disk shape. Average lifespan of 120 days. Normal RBC:WBC ratio is approximately 600:1 and RBC:Platelets ratio is 15:1.

RBC Membrane

RBC membrane composition: 8% carbohydrates, 40% lipids, 52% proteins (integral and peripheral).
Transmembrane proteins: Include channel ions, water, and glucose. Provide vertical support connecting the lipid bilayer to the underlying cytoskeleton. Maintain membrane integrity.
- Examples: Aquaporin 1, Band 3, Ca²⁺-ATPase, Duffy, Glut-1.
- Function:
  - Aquaporin 1: Water transporter
  - Band 3: Anion transporter, supports ABH antigens
  - Ca²⁺-ATPase: Ca²⁺ transporter, supports Duffy antigen
  - Duffy: Supports Duffy antigen
  - Glut-1: Glucose transporter, supports ABH antigens

Test your knowledge on the development stages of erythrocytes, including pyrenocytes, reticulocytes, and mature red blood cells. Understand the structure and composition of the RBC membrane and its components. This quiz will help you grasp the essential biology behind red blood cell formation and function.