Exocytosis, also known as exocytosis, is to expel the residual body after the degradation of exogenous substances ingested by endocytosis and pinocytosis from the cell.
Exogenous substances ingested by endocytosis and pinocytosis are engulfed by invaginated vacuoles to form phagosomes, or phagocytes. Then the phagosomes will fuse with the primary lysosomes to form the secondary lysosomes.
Some people advocate that the secondary lysosome formed by ingesting foreign substances is called heterogeneous lysosome. This can be distinguished from the self lysosome formed by intake of endogenous substances. In the secondary lysosome, exogenous substances will be degraded by lysosomal hydrolase.
- Foreign name
- exocytosis
- Alias
- Efflux of cell contents
- Chinese scientific name
- Exocytosis
- circles
- Animal kingdom
- Role
- Intracellular transport of macromolecular substances
- Example
- Proenzyme secreted by pancreatic cells
- Features
- Energy consumption does not pass through the plasma membrane to increase the membrane area
- Classification
- Constitutive exocytosis regulatory exocytosis
Exocytosis is the process of transporting the substances in the membrane vesicles out of the cells through the fusion of the secretion vesicles or other membrane vesicles with the plasma membrane. It is the way of transporting macromolecular substances in the cells. Cells secrete substances outward through exocytosis Cell secretion The zymogen granule (protein) is a kind of exocytosis. Exocytosis requires energy consumption;
The substances transported by exocytosis do not cross the membrane structure. Exocytosis reflects the characteristics of cell membrane structure - the fluidity of biofilm;
The fusion of vesicles and plasma membrane occurs during exocytosis, which will increase the surface area of plasma membrane.
In multicellular organisms, there are two types of exocytosis [1] ：
Constitutive exocytosis pathway: Eukaryotic cell A stable process in which vesicles secreted from the TGN on the reverse side of Golgi apparatus flow into the plasma membrane and fuse with it. Newly synthesized proteins and lipids continuously supply plasma membrane renewal in this way; Soluble proteins in vesicles can be secreted out of cells, and some become plasma membranes Peripheral protein Some become extracellular matrix components, and some diffuse to extracellular fluid as nutrients or signal molecules. Regulated exocytosis pathway: specialized Cell secretion The secretions produced (such as hormones, mucus or digestive enzymes) are not immediately secreted outside the cell but stored in Secretory cell When cells are stimulated by extracellular signals, the secretory vesicles fuse with the plasma membrane and release the contents. Intracellular Macromolecular substances Transport, such as the secretion of extracellular proteins. 
