Unit I

Mucous salivary gland: The secretion is predominantly mucous in character. The duct system is similarto that in the parotid gland. The mucous secretory units are packed within a lobule. They are largercompared to the serous alveoli and are lined by simple columnar cells resting on a basement membrane.The mucous cells are pale staining because the mucinogen granules is washed during staining. The lumen islarger and easily seen while the nuclei are flat near the basement membrane.Mucous alveolus: The columnar cells of a mucous alveolus rest on a basement membrane. The nucleus ofeach cell is flat with a long axis parallel to the basement membrane. The nucleus is disk like and is squeezedup against the bases of the cells.The basal cytoplasm is less basophilic. The larger part of the cytoplasm issupranuclear containing membrane bound vesicles of mucous as in unicellular goblet cells. The mucous isa glycoprotein so it does not stain with H & E and hence the cytoplasm is pale and vacuolated. Thesevacuoles are best stained with PAS staining method.Notes:59