apokriinisista

Apokriinisista is a term used in biology, specifically in histology and cytology, to describe a mode of secretion by glands. In this type of secretion, the apical portion of the cell, along with its stored secretory products, breaks away from the cell body. This detached portion then disintegrates, releasing the secretions. The remaining cell body then regenerates its apical portion to repeat the process. This contrasts with merocrine secretion, where vesicles fuse with the cell membrane to release their contents without cellular damage, and holocrine secretion, where the entire cell disintegrates to release its secretions.

Examples of apocrine glands include the mammary glands, which secrete milk by this mechanism, and certain sweat glands, particularly the apocrine sweat glands found in the axillae and groin. The secretions from apocrine glands are often rich in lipids and other complex molecules. The process involves the formation of secretory vesicles at the apical end of the cell. These vesicles accumulate and eventually cause the apical membrane to bulge outwards. The membrane then pinches off, forming a larger vesicle or droplet containing the secretory material. This detached apical fragment is then released from the gland. The cell then repairs itself and begins the process of accumulating new secretory products.