Apokrineissä

Apokrineissä is a term used in biology, specifically in the study of glands and cellular secretion. It refers to a mode of secretion where a portion of the cell's cytoplasm, along with the secretory product, is pinched off and released from the cell. This is distinct from merocrine secretion, where the cell releases its product without any loss of cytoplasm, and holocrine secretion, where the entire cell disintegrates to release its contents.

In apocrine secretion, the secretory vesicles accumulate near the apical (outer) surface of the cell. As the secretion is released, the cell membrane surrounding the vesicles also breaks and detaches, taking a portion of the cytoplasm with it. The remaining part of the cell then regenerates to produce more secretion. This type of secretion is often associated with the production of oily or lipid-rich substances.

Examples of apocrine glands in mammals include certain sweat glands, such as the mammary glands which produce milk, and the ceruminous glands in the ear canal, which produce earwax. The sebaceous glands, which produce sebum (oil) for the skin and hair, are also sometimes described as exhibiting apocrine secretion, though they are more commonly classified as holocrine. The precise mechanism of secretion can sometimes be debated, and some glands may show characteristics of more than one type. Understanding the mode of secretion is important for comprehending the physiological function and biochemical composition of the substances released by these glands.