Reticuloendothelial System (Macrophage System)

Definition:

Reticuloendothelial system is part of the immune system of human body and consists of phagocytic cells. It is closely related to lymphatic system because the two are independent structurally and functionally. ThisĀ  system is made up of highly phagocytic cells which are widely distributed in the body. These cells include:

  1. Macrophages of connective tissue, reticular tissue and lungs

    Macrophage

    Macrophage (Source=Arcadian/Wikipedia)

  2. Monocytes of blood

    Monocyte

    Monocyte (Source: Arcadian/Wikipedia)

  3. Kupffer’s cells of liver

    Kupffer's Cells of Liver

    Kupffer's Cells of Liver (Source: Nephron/Wikipedia)

  4. Meningocytes of meninges
  5. Microglial cells of nervous tissue

    Microglial Cells

    Microglial Cells

  6. Foreign body giant cells.

    Foreign Body Giant Cell

    Foreign Body Giant Cell

The endothelial cells, fibroblasts, and most leukocytes arc not included in this system because of their poor power of phagocytosis.

Functions of Reticuloendothelial system:

1. The system forms first line of defense of the body against microorganisms, because of the amoeboid and phagocytic properties of its cells.
2. The macrophages of lymphoid tissue are now considered to be intimately concerned with mounting specific immune responses by the neighboring cells.
3. Many of the prominent sites of RES are also important sites of hemopoiesis.