A goblet cell is a glandular, modified simple columnar epithelial cell whose function is to secrete gel-forming mucins, the major components of mucus. The goblet cells mainly use the merocrine method of secretion, secreting vesicles into a duct, but may use apocrine methods, budding off their secretions, when under stress. The goblet cell is highly polarised with the nucleus and other organelles concentrated at the base of the cell. The remainder of the cell's cytoplasm is occupied by membrane-bound secretory granules containing mucin. The goblet shape is due to the mucus laden granules in the apical part expanding, causing that part of the cell to balloon. The apical plasma membrane projects microvilli to give an increased surface area for secretion.