Meaning of Exocytosis

What is Exocytosis:

Exocytosis is the process by which cells release large molecules for use by other cells or by the body in different biological processes.

In exocytosis, proteins or molecules produced in the endoplasmic reticulum are wrapped in a vesicle to the Golgi apparatus, where they are fused and processed.

Then, the newly processed molecule travels back into another vesicle to be released from the Golgi apparatus to fuse with the endoplasmic membrane of the cell wall, where it will finally be released to the outside of the cell.

See also:

  • Golgi apparatus.
  • Endoplasmic reticulum.

Types of Exocytosis

Cells use exocytosis to release the molecules, proteins or lipids, that the organism needs. In this sense, there are two types of exocytosis: constitutive exocytosis and regulated exocytosis.

constitutive exocytosis

Constitutive exocytosis is one that occurs in all cells. The released molecules help the formation of the extracellular matrix and for the regeneration of the plasmatic membrane.

regulated exocytosis

Regulated exocytosis is the process of specialized cells in secretion. They release molecules that perform specific functions in the body or affect the physiology of other cells.

Regulated exocytosis differs from constitutive exocytosis in that they fail to spontaneously fuse with the plasma membrane. Due to the specific functions that they carry, they need a specific signal to be released.

Some cells with regulated exocytosis are, for example, hormone-producing cells, neurons, cells of the digestive epithelium, and granule cells.

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Exocytosis and endocytosis

Endocytosis is the opposite process to exocytosis. In both cases, the molecules are transported wrapped in vesicles outside the cell’s plasma membrane, in the case of exocytosis, or inside the cell in the case of endocytosis.

See also Endocytosis.