In which bodily organ are senescent erythrocytes selectively eliminated and recycled by macrophages?
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Answer: A. Spleen
Explanation
Specialized macrophages lining splenic cords continuously monitor the physical flexibility of circulating red blood cells. Old erythrocytes lose membrane elasticity and become trapped within the tight sinusoidal spaces of the spleen. Phagocytic macrophages engulf these damaged cells and recycle their iron and globin protein components efficiently. Healthy red blood cells circulate in the human bloodstream for an average lifespan of about 120 days. The spleen is the largest lymphatic organ and plays crucial roles in filtering blood and mounting immune responses. Heme from destroyed hemoglobin is broken down into bilirubin and iron for safe bodily reuse.
Splenic filtration prevents damaged fragile cells from clogging microvascular beds throughout the circulatory system. Patients who undergo surgical removal of the spleen face increased risks of certain bacterial infections. Doctors evaluate spleen enlargement to diagnose various hematological disorders and infectious diseases. The kidney filters metabolic wastes from blood plasma to form urine rather than destroying blood cells. The liver processes nutrient laden blood from the digestive tract and produces vital plasma proteins. The pancreas functions primarily as a glandular organ secreting digestive enzymes and blood sugar hormones.
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