Sweat glands

Sweat gland
A cross-section of the human skin, with the sweat gland labeled at the bottom
Details
Precursor	Ectoderm
System	Integumentary
Nerve	Eccrine: cholinergic sympathetic nerves Apocrine: adrenergic nerves
Identifiers
Latin	Glandula sudorifera
MeSH	A10.336.899
TA	A16.0.00.029
FMA	59152
Anatomical terminology []

Sweat glands, also known as sudoriferous or sudoriparous glands, from Latin sudor, meaning 'sweat', are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial surface by way of a duct. There are two main types of sweat glands that differ in their structure, function, secretory product, mechanism of excretion, anatomic distribution, and distribution across species:

Ceruminous glands (which produce ear wax), mammary glands (which produce milk), and ciliary glands in the eyelids are modified apocrine sweat glands.

Generally, sweat glands consist of a secretory unit consisting of a base rolled into a , and a duct that carries the sweat away. The secretory coil or base, is set deep in the lower dermis and hypodermis, and the entire gland is surrounded by adipose tissue. In both sweat gland types, the secretory coils are surrounded by contractile myoepithelial cells that function to facilitate excretion of secretory product. The secretory activities of the gland cells and the contractions of myoepithelial cells are controlled by both the autonomic nervous system and by the circulating hormones. The distal or apical part of the duct that opens to the skin's surface is known as the acrosyringium.

Each sweat gland receives several nerve fibers that branch out into bands of one or more axons and encircle the individual tubules of the secretory coil. Capillaries are also interwoven among sweat tubules.

The number of active sweat glands varies greatly among different people, though comparisons between different areas (ex. axillae vs. groin) show the same directional changes (certain areas always have more active sweat glands while others always have fewer). According to Henry Gray's estimates, the palm has around 370 sweat glands per cm²; the back of the hand has 200 per cm²; the forehead has 175 per cm²; the breast, abdomen, and forearm have 155 per cm²; and the back and legs have 60–80 per cm².