MICROANATOMY

BLOOD CARDIOVASCULAR SYSTEM LYMPHOID ORGANS

BLOOD

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
How long do erythrocytes live?
A
forever
B
100-120 days
C
2 weeks only
D
a year
Explanation: 

Detailed explanation-1: -The lifespan of a red blood cell is around 120 days.

Detailed explanation-2: -Human red blood cells (RBC), after differentiating from erythroblasts in the bone marrow, are released into the blood and survive in the circulation for approximately 115 days.

Detailed explanation-3: -Normal human red blood cells have an average life span of about 120 days in the circulation after which they are engulfed by macrophages. This is an extremely efficient process as macrophages phagocytose about 5 million erythrocytes every second without any significant release of hemoglobin in the circulation.

Detailed explanation-4: -Human red blood cells (RBCs) are normally phagocytized by macrophages of splenic and hepatic sinusoids at 120 days of age. The destruction of RBCs is ultimately controlled by antagonist effects of phosphatidylserine (PS) and CD47 on the phagocytic activity of macrophages.

Detailed explanation-5: -Red blood cells have a limited lifespan because they don’t have a center membrane (nucleus). When a red blood cell travels through your blood vessels, it uses up its energy supply and only survives an average of 120 days.

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