Reticuloendothelial System.

 Reticuloendothelial System.

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Introduction:

• Reticuloendothelial System also called mononuclear phagocytic system (MPS) consists of phagocytes located in reticular connective tissues.

Cell types and locations:

• The monocyte is formed in the bone marrow and transported by the blood; it migrates into the tissues, where it transforms into a histiocyte or a macrophage.

• The half-life of blood monocytes is about 1 day, whereas the life span of tissue macrophages is several months or years. 

• The mononuclear phagocyte system is part of both humoral and cell-mediated immunity. 

• The mononuclear phagocyte system has an important role in defense against microorganisms, including mycobacteria, fungi, bacteria, protozoa, and viruses. 

• Macrophages remove senescent erythrocytes, leukocytes.

Cell Name.	Location
Adipose tissue macrophages	Adipose tissue
Monocyte	Bone Marrow/Blood
Kupffer cell	Liver
Sinus histiocytes	Lymph nodes
Alveolar macrophage(dust cell)	Pulmonary alveolus of Lungs
Langerhans cell	Skin and Mucosa
Microglia	Central Nervous System
Hofbauer cell	Placenta
Intraglomerular mesangial cell	Kidney
Red Pulp Macrophage	Spleen.
Peritoneal macrophages	Peritoneal cavity.

Functions:

1. Formation of new red blood cells (RBCs) and white blood cells (WBCs).

2. Destruction of senescent (Growing Old) RBCs.

3. Formation of plasma proteins.

4. Formation of bile pigments.

5. Storage of iron. In the liver, Kupffer cells store excess iron from catabolism of heme from the breakdown of red blood cells.

6. Clearance of heparin via heparinases.

Commonly Asked Question:

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