5.16胞吞作用

Exocytosis is the process in which substances produced inside a eukaryotic cell are secreted out through the fusion of membrane-bound vesicles to the plasma membrane.
For example, initially, signaling molecules, like a peptide hormone, leave the endoplasmic reticulum packaged along with other membrane components in a transport vesicle. This cargo proceeds through the cisternae of the golgi appratus, continuously budding and fusing until the contents reach the trans-golgi network.
Here they aggregate, bud off into vesicles once again, and finally head towards their target, the plasma membrane, where the membranes of the vesicle and cell fuse, releasing the signal into the extracellular space.