Which type of endocytosis involves the uptake of small extracellular fluid droplets?
Cells internalize extracellular material by mechanistically distinct endocytic routes distinguished by particle size, actin requirement, coat dependence. Phagocytosis mediates uptake large particulates above 0.5 micron such as bacteria, yeast, dead cells via extension actin-driven pseudopods triggered clustering Fc gamma receptors, complement receptors CR3, scavenger receptors signaling via Syk, PI3K, Rho GTPases prominent professional phagocytes macrophages neutrophils forming phagosome destined lysosome. Pinocytosis literally cell drinking from Greek pinein describes constitutive uptake smal
Ref: Alberts et al., MBC Chapter 13: Pinocytosis for fluid-phase uptake.