Apocrine

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405 Modes of Secretion by Glands Apocrine

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Apocrine

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Histology of apocrine cells

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Histopathology of apocrine metaplasia of breast, annotated

Apocrine glands are a type of exocrine gland that is found in various parts of the human body. These glands are responsible for producing and secreting substances onto the surface of the skin or into the hair follicles. Unlike eccrine glands, which secrete sweat directly onto the skin surface, apocrine glands release their secretions into the hair follicle, which then reach the skin surface. Apocrine secretions are initially odorless, but they can become odorous upon interaction with bacteria on the skin surface. These glands play a significant role in the body's thermoregulation and are also involved in scent communication.

Anatomy and Physiology

Apocrine glands are most abundant in areas rich in hair follicles, such as the armpits, groin, and areolas of the breasts. They are larger than eccrine sweat glands and are located deeper in the dermis or in the subcutaneous tissue. The secretions of apocrine glands are milky or viscous and contain proteins, lipids, and steroids. These components make the secretions an ideal growth medium for certain bacteria, contributing to the characteristic body odor associated with sweat.

The development of apocrine glands begins in late fetal development and these glands become fully functional at puberty, suggesting a role influenced by hormones, particularly androgens. The activity of apocrine glands is also thought to be related to emotional stress and sexual excitement.

Function

The primary function of apocrine glands is not entirely understood, but they are believed to play roles in scent communication, territorial marking, and in the case of the mammary glands, milk production. The secretions of apocrine glands are thought to contain pheromones, which are chemicals that can influence the behavior or physiology of others of the same species.

Clinical Significance

Apocrine glands can be involved in several dermatological conditions. One of the most common conditions is hidradenitis suppurativa, a chronic inflammatory skin condition that affects areas bearing apocrine sweat glands. It is characterized by recurrent boil-like lumps, scarring, and tract formation. Another condition related to apocrine glands is apocrine miliaria, also known as Fox-Fordyce disease, which is a rare chronic inflammatory disorder resulting in itchy papules in areas where apocrine glands are located.

See Also

• Sweat gland
• Eccrine gland
• Hidradenitis suppurativa
• Pheromones