Describe the structure and different properties of RBC?

Introduction to Red Blood Cells:

   The non-nucleated formed elements of the blood ,red blood cells are also known as erythrocytes (erythros=red).

A special pigmented protein namely haemoglobin (iron containing coloring material) is present in the cytoplasm of the RBC. Haemoglobin forms 90%of the total weight of the RBC.

The red colour of the RBCs,and thus of the blood,is due to the presence of the haemoglobin.

RBC has a significant role in the transport of respiratory gases.

The number of RBC present in the blood is greater than the other two types of formed element present in the blood namely white blood cell and platelets.

Red Blood Cell

Normal counts of RBC:

• At birth normal RBC count is 6-7million/mm³.
• In adult males normal RBC count varies from 5-6.5million/mm³.
• In females,it varies from 4.5-5.5 million/mm³.

Normal shape of RBC:

  Normally the RBCs are disk shaped and biconcave (dumbbell).

Peripheral portion of the RBC is thicker and central portion of the RBC is thinner.

Biconcave shape of RBC

Advantages of biconcave shape of RBCs:

 The biconcave shape of RBCs has some mechanical and functional advantages.

1. Because of the biconcave shape of the RBC, equal and rapid diffusion of oxygen and other substances into the interior of the cell is possible.
2. Easy exchange of O2 and CO2 and rapid diffusion of other substances is possible because of the greater surface area of the RBC.
3. When the volume of cell changes, biconcavity provides minimum tension on the membrane.
4. RBCs squeeze through the capillaries very easily without getting damaged,when they pass through the minute capillaries, because the biconcave shape protects them from getting damaged.

Normal size of Red blood cells:

• Diameter of each RBC is 7.2µm(range 6.9-7.4µm)
• In the periphery thickness of RBC is 2µm and in the centre is 1µm.
• Surface area of each RBC is about 120-140μm².
• And volume of each RBC is about 80µm³(range 78-86µm³).
  
  

The structure of RBC:

 Red blood cell does not contain any nucleus.DNA is absent in the RBC because of the absence of the nucleus.

Other cellular organelles such as mitochondria(the power house of the cell) and golgi apparatus are also absent in the red blood cells.

Also read

• Short note||Functional anatomy of the human heart.

• Property,composition and functions of blood

• What are plasma proteins? Describe the origin, properties and function of plasma protein?

• Describe the different phases of meiosis 1.

• Histological structure of pancreas

Mitochondria is involves in the production of energy in the form of ATP . As there is no mitochondria in the RBC that's why, energy produced from the glycolytic process.

Each erythrocyte contains approximately 280 million haemoglobin molecules,which gives blood it's red color.

Each day bone marrow produce approximately 200 billion red blood cells.

There is present a special type of cytoskeleton in the RBC ,which is made up of actin and spectrin.

Both the proteins are anchored to the transmembrane proteins by means of another protein called ankyrin.

Properties of Red Blood Cells:

 Specific gravity of RBC:

    Specific gravity of RBC is 1.092-1.101.

Suspension stability:

 During circulation the red blood cells remain suspended uniformly in the blood . This property of the RBCs is called the suspension stability.

Lifespan of Red Blood Cells:

   Average lifespan of RBC is about 120 days.After the lifetime the senile (old) RBCs are destroyed in the reticuloendothelial system.

➡️If you like this post please🙏 share it with your friends. Your one share can help someone.