In biology, caveolae (Latin for little caves, single: caveola) are small (50–100 nanometer) invaginations of the plasma membrane in many vertebrate cell types, especially in endothelial cells and adipocytes. Some cell types, like neurons, may completely lack caveolae. These flask-shaped structures are rich in proteins as well as lipids such as cholesterol and sphingolipids and have several functions in signal transduction (Anderson, 1998). They're also believed to play a role in endocytosi… (More on Caveolae)