GLOSSARY

Pinocytosis is a type of endocytosis in which a cell takes in small droplets of extracellular fluid together with the molecules dissolved in it.
The term derives from the Greek pinein, meaning “to drink,” and it is therefore also called cell drinking.

Mechanism and Features

In pinocytosis, the cell membrane folds inward and pinches off very small vesicles containing the fluid surrounding the cell.
The process is usually non-specific; that is, the cell takes up whatever substances are dissolved in the droplet without selection.
Pinocytosis occurs continuously in almost all cells and acts as an ongoing sampling of the surrounding environment.