apokrins

Apocrine glands, or apokrine sweat glands, are a type of sweat gland in humans and other mammals. They are larger than eccrine glands and their secretions are typically viscous and rich in proteins and lipids. Unlike eccrine glands, which drain directly to the skin surface, apocrine glands usually release their secretions into hair follicles, and some specialized apocrine glands open into different structures, such as the ear canal (ceruminous glands) or the eyelids (glands of Moll).

Distribution and structure show that apocrine glands are concentrated in areas with extensive hair growth, notably the axillae (armpits), the anogenital region, and the areolae. They can be present in other regions as well, and ceruminous glands in the external auditory canal are considered apocrine-type glands. The ducts are lined by secretory cells supported by myoepithelial cells. The secretion mechanism is described as apocrine or decapitation secretion, in which the apical portion of the secretory cell pinches off to release the product, with the remaining cell regenerating.

Function and development are influenced by androgens; apocrine glands become active at puberty and respond to emotional and sexual stimuli. The secretions themselves are odorless when produced but can develop a characteristic body odor after bacterial decomposition on the skin, contributing to bromhidrosis in some individuals.

Clinical relevance includes conditions affecting apocrine-bearing regions, such as hidradenitis suppurativa, which involves inflammation of apocrine glands and surrounding tissue. Rare tumors, including apocrine adenomas and carcinomas, can arise from these glands. Overall, apocrine glands contribute to the body's scent-related biology and are distinguished from eccrine sweat glands by their location, secretion composition, and secretion mechanism.