<P> Goblet cells are simple columnar epithelial cells that secrete gel - forming mucins, like mucin MUC5AC . 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 term goblet refers to the cell's goblet - like shape . The apical portion is shaped like a cup, as it is distended by abundant mucus laden granules; its basal portion lacks these granules and is shaped like a stem . </P> <P> The goblet cell is highly polarized with the nucleus and other organelles concentrated at the base of the cell and secretory granules containing mucin, at the apical surface . The apical plasma membrane projects microvilli to give an increased surface area for secretion . </P> <P> Goblet cells are typically found in the respiratory, reproductive and gastrointestinal tracts and are surrounded by stratified squamous cells . Differentiation of epithelial cells into goblet cells plays a key role in the excessive mucus production seen in many diseases, such as asthma and cancer . </P> <P> Goblet cells are found scattered among the epithelial lining of organs, such as the intestinal and respiratory tracts . They are found inside the trachea, bronchi, and larger bronchioles in the respiratory tract, small intestines, the large intestine, and conjunctiva in the upper eyelid . In the conjunctiva goblet cells are a source of mucin in tears and they also secrete different types of mucins onto the ocular surface . In the lacrimal glands, mucus is synthesized by acinar cells instead . </P>

In what subtypes of epithelial tissue are goblet cells usually found