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The Role Of Sweat Glands In The Body

Sweat glands is 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.

Eccrine sweat glands are distributed almost all over the human body, in varying densities, with the highest density in palms and soles, then on the head, but much less on the trunk and the extremities. Its water-based secretion represents a primary form of cooling in humans.

Apocrine sweat glands are mostly limited to the axilla (armpits) and perianal areas in humans. They are not significant for cooling in humans, but are the sole effective sweat glands in hoofed animals, such as the camels , donkeys, horses, and
cattle.

Sweat

Sweat glands are used to regulate temperature and remove waste by secreting water, sodium salts, and
nitrogenous waste (such as urea) onto the skin surface.The main electrolytes of sweat are sodium and
chloride,though the amount is small enough to make sweat hypotonic at the skin surface. Eccrine sweat is clear, odorless, and is composed of 98–99% water; it also contains NaCl,
fatty acids,lactic acid,citric acid,
ascorbic acid,urea,and uric acid . Its
pH ranges from 4 to 6.8.

On the other hand, the apocrine sweat has a pH of 6 to 7.5; it contains water, proteins, carbohydrate waste material, lipids, and steroids.The sweat is oily, cloudy,viscous, and originally odorless; it gains odour upon decomposition by bacteria.Because both apocrine glands and sebaceous glands open into the hair follicle,apocrine sweat is mixed with sebum.

Diseases of the sweat glands

Fox-Fordyce disease
The apocrine sweat glands become inflamed, causing a persistent,itchy rash,usually in the axillae and pubic areas.

Frey's Syndrome

If the auriculotemporal nerve is damaged (most often as a result of a Parotidectomy), excess sweat can be produced in the rear of the cheek area (just below the ear) in response to stimuli that cause salivation.

Heatstroke

When the eccrine glands become exhausted and unable to secrete sweat. Heatstroke can lead to fatal
hyperpyrexia (extreme rise in body temperature).

Hyperhidrosis

Also known as polyhidrosis or
sudorrhea) is a pathological,excessive sweating that can be either generalized or localized (focal hyperhidrosis ); focal hyperhidrosis occurs most often on the palms,soles,face,scalp and axillae.Hyperhidrosis is usually brought on by emotional or thermal stress, but it can also occur or with little to no stimulus.Local (or asymmetrical) hyperhidrosis is said to be caused by problems in the
sympathetic nervous system : either lesions  or nerve inflammation.Hyperhidrosis can also be caused by trench foot or
encephalitis.

Milaria rubra

Also called prickly heatodouraria rubra is the rupture of sweat glands and migration of sweat to other tissues. In hot environments, the skin's horny layer can expand due to sweat retention, blocking the ducts of eccrine sweat glands. The glands, still stimulated by high temperatures, continues to secrete. Sweat builds up in the duct, causing enough pressure to rupture the duct where it meets the epidermis. Sweat also escapes the duct to adjacent tissues (a process called milaria).Hypohydrosis then follows milaria (postmiliarial hypohydrosis).

Osmidrosis

Often called bromhidrosis, especially in combination with hyperhidrosis. Osmohidrosis is excessive odour from apocrine sweat glands (which are overactive in the axillae).Osmidrosis is thought to be caused by changes in the apocrine gland structure rather than changes in the bacteria that acts on sweat.

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