Zymogen granules. The granules stay in the apex until the cells is stimulated to secrete 3. Mixed contain both serous and mucus. Methods of secretion 1. Merocrine (eccrine) this glands have secretory vesicles that release their secretion by exocytosis without loss of cytoplasm e.g. Tear gland, pancreas, gastric gland. 2. Holocrine glands: cells accumulate a product and then the entire cell fragments and the substance the cell had synthesized prior to its disintegration holocrine secretory tend to be thicker than merocrine secretion. e.g.: sebaceous gland. 3. Apocrine gland : the secretion was produced by bits of apical cytoplasm , breaking A way from the cell. Secretory products discharged together with the apical cytoplasm. E.g.: mammary gland, sweet gland.