Lacrimal Gland Overview

The lacrimal gland is responsible for the production of most of the proteins, electrolytes, and fluid constituting the aqueous layer of the tear film. The gland is comprised of multiple cell types including the most abundant acinar epithelial cells as well as ductal epithelial cells, myoepithelial cells, and resident immune cells. Innervation of the gland by parasympathetic and sympathetic neurons leads to release of neurotransmitters that activate basolateral acinar cell receptors to signal to the exocytotic apparatus to provoke release of sequestered proteins from secretory vesicles. Movement of proteins through the transcytotic pathway is also accelerated by acinar receptor activation. Proteins released by the lacrimal gland sustain corneal integrity, protect the ocular surface from infection, and aid in recovery from injury. Neurotransmitters also stimulate fluid and electrolyte flow into lacrimal fluid through a complex activation of channels and transporters in acinar and ductal cells.