Apocrine

Apocrine gland

Exocrine Secretion

Merocrine or eccrine – by exocytosis

Apocrine – by membrane budding (decapitation secretion)

Holocrine – by membrane rupture

Apocrine is a term used to classify exocrine glands in the study of histology. Cells which are classified as apocrine bud their secretions off through the plasma membrane producing membrane-bound vesicles in the lumen. This method is also called decapitation secretion. The apical portion of the secretory cell of the gland pinches off and enters the lumen.

Apocrine secretion is less damaging to the gland than holocrine secretion (which destroys a cell) but more damaging than merocrine secretion (exocytosis).

Apocrine sweat glands are not true apocrine glands; it is now known that they use merocrine secretion. The name is maintained for historical reasons.

An example of true apocrine glands are mammary glands, responsible for secreting breast milk.

Apocrine metaplasia

Main article: Metaplasia

Micrograph showing apocrine metaplasia (right bottom of image - light pink columnar epithelium) in the context of fibrocystic breast changes. H&E stain.

Apocrine metaplasia is a reversible transformation of cells to an apocrine phenotype. It is common in the breast in the context of fibrocystic change.

External links

• apocrine at eMedicine Dictionary
• 1624244281 at GPnotebook
• Diagram at uwa.edu.au