Phagocytosis: Form Of Endocytosis That Allows Macrophages.

A phagocytosis is a form of endocytosis that includes the engulfing of large cells or particles. Phagocytosis allows immune cells, like virus-infected cells, to rid the body of bacteria, cancer cells, macrophages, or extra harmful substances. It is the process by which organisms like amoebas contain food from their environment.

In phagocytosis, the phagocyte or phagocytic cell must be able to attach to the target cell, degrade it, and expel the refuse, internalize it. This method, as it occurs in immune cells, is explained below.

Basic steps of Phagocytosis

Detection: The phagocytes detects the antigen substance provoking an immune response, such as a bacterium, and moves towards the target cell. 

Attachment: The Phagocyte makes contact with and attaches to the bacterium. This binding initiates the development of pseudopodia extensions of the cell that surround the bacterium.

Ingestion: The surrounded bacterium is enclosed within a vesicle formed when pseudopodia membranes fuse. This swelling with the bacterium enclosed, called a phagosome, is internalized by the phagocytes.

Fusion: The phagosome fuses with an organelle called a lysosome and becomes known as a phagolysosome. The lysosome contains enzymes that absorb organic material. The relief of digestive enzymes within the phagolysosome degrades the bacterium.

Elimination: The depraved material is ejected from the cell by exocytosis. Phagocytosis in protists happens similarly and more commonly as it is the means by which these organisms receive food. Phagocytosis in humans is only achieved by specialized immune cells.