Sweat glands , also known as sudoriferous or sudoriparous glands , from Latin sudor , meaning 'sweat' small-sized tubular structure of the skin that produces perspiration. Sweat glands are a kind of exocrine gland, a gland that produces and releases substances to the epithelial surface through a duct. There are two main types of different sweat glands in structure, function, secretory product, excretory mechanism, anatomical distribution, and distribution between species:
- Eccrine's sweat glands are distributed almost throughout the human body, in various densities, with the highest density in the palms of the hands and soles of the feet, then in the head, but much less in the stems and extremities. Its water-based secretion is the main form of cooling in humans.
- Apocrine sweat glands are mostly confined to the underarm (armpit) and perianal areas of the human. They are not significant for cooling in humans, but are the only effective sweat glands in hoofed animals such as camels, donkeys, horses, and livestock.
The gland gland (which produces earwax), the milk glands (which produce milk), and the ciliary glands on the eyelids are altered apocrine sweat glands.
Video Sweat gland
Structure
Generally, sweat glands consist of a secretor unit which consists of a base that is rolled into a glomerulum, and a channel that brings the sweat away. The
Each sweat gland receives several nerve fibers that branch off into bands of one or more axons and surround the individual tubules of the secretory coil. Capillaries are also intertwined among the sweat tubules.
Maps Sweat gland
Distribution
The number of active sweat glands varies greatly among different people, although comparisons between different areas (ex Axillae vs. crotch) show the same direction change (certain areas always have more active sweat glands while others always have less). According to Henry Gray's estimates, the palm has about 370 sweat glands per cm 2 ; the back of the hand has 200 per cm 2 ; forehead has 175 per cm 2 ; breast, abdomen, and forearm have 155 per cm 2 ; and the back and legs have 60-80 per cm 2 .
In the finger pad, the sweat glands are somewhat irregular on the epidermal back. There are no pores between the bulges, though sweat tends to spill into them. The thick epidermis of the palms and soles of the feet causes the sweat glands to spiral in a circle.
Animal
Non-primate mammals have eccrine sweat glands only in the palms of the hands and soles of the feet. Apocrine glands cover the entire body, although they are not as effective as humans in the temperature setting (with the exception of horses'). Prosimians have a ratio of 1:20 follicles to apocrine glands versus non-follicular follicles. They have eccrine glands between the hairs in most of their bodies (while humans have them between the hairs on their scalp).
The overall distribution of sweat glands varies among primates: rhesus and patas monkeys have them in the chest; squirrel monkeys have them only in the palms of the hands and soles of the feet; and puffer-tailed monkeys, Japanese monkeys, and baboons have it all over the body.
Domestic animals have apocrine glands at the base of every hair follicle, but eccrine glands are only in the foot pads and muzzles. Their apocrine glands, like those in humans, produce an odorless oily milk secretion that evolves to not evaporate and cool, but coat and stick to the hair so that the odor-causing bacteria can grow on it. The eccrine glands on the cushions of their feet, like those in the palms of the hands and the palms of humans, have not evolved to be cool either but rather increase friction and increase clutches.
Dogs and cats have apocrine glands that specialize in structures and functions located in the eyelids (Moll glands), ears (ceruminous glands), rectal sacs, vulvar prepuce, and circumscribed areas.
Type
Eccrine
Eccrine's sweat glands are everywhere except lips, ear canal, prepuce, penis glans, labia minora, and clitoris. They are ten times smaller than the apocrine sweat glands, do not extend into the dermis, and expel directly to the skin surface. The proportion of eccrine glands decreases with age.
A clear secretion produced by the eccrine sweat gland is called sweat or a reasonable sweat . Sweat is mostly water, but it contains some electrolytes, because it comes from blood plasma. The presence of sodium chloride provides a sweat of saltiness.
The total volume of sweat produced depends on the number of functional glands and the size of the surface opening. Levels of secretive activity are governed by neuronal and hormonal mechanisms (men are more sweating than women). When all of the eccrine sweat glands work at maximum capacity, the level of sweat for humans can exceed three liters per hour, and the danger of fluid and electrolyte loss can occur.
The eccrine gland has three main functions:
- Thermoregulation: perspiration cools the surface of the skin and reduces body temperature.
- Excretion: eccrine sweat gland secretion may also provide significant excretory routes for water and electrolytes.
- Protection: secretion of eccrine gland sweat gland in preserving the skin acid coat, which helps protect the skin from colonization of bacteria and other pathogenic organisms.
Apocrine
Apocrine sweat glands are found in the armpit, areola (around the nipple), perineum (between the anus and genitals), in the ears, and in the eyelids. The secretion section is larger than the eccrine gland (making them bigger overall). Instead of opening directly to the skin surface, apocrine glands secrete sweat into the hair follicle root canal.
Before puberty, apocrine sweat glands are inactive; Hormonal changes during puberty cause the gland to grow larger and begin to function. The secreted substance is thicker than eccrine sweat and provides nutrients for bacteria on the skin: the breakdown of bacteria from the sweat creates a sharp odor. Apocrine sweat glands are most active at times of stress and sexual arousal.
In mammals (including humans), apocrine sweat contains compounds such as pheromones to attract other organisms within their species. Studies of human sweat have revealed differences between men and women in apocrine and bacterial secretions.
Apoeccrine
Some human sweat glands can not be classified as apocrine or ekrin, having both characteristics; The gland is called apoeccrine . They are larger than the eccrine glands, but smaller than the apocrine glands. Their secretion section has a narrow section similar to the secretory coil in the eccrine gland as well as the large part that reminds the apocrine gland.
Apoeccrine, found in the armpits and perianal areas, has an open channel to the skin surface. They are thought to have developed in puberty from the eccrine glands, and can comprise up to 50% of all axillary glands. The Apoeccrine glands secrete more sweat than the eccrine and apocrine glands, thereby playing a major role in axillary sweat. Apoeccrine glands are sensitive to cholinergic activity, although they can also be activated through adrenergic stimulation. Like the eccrine glands, they constantly release a watery thin sweat.
More
Special sweat glands, including ceruminous glands, milk glands, eyelids ciliary glands, and sweat glands from nasal vestibulum, are modified apocrine glands. Serumin glands close to the ear canal, and produce cerumen (ear wax) mixed with oil secreted from sebaceous glands. The mammary glands use apocrine secretions to produce milk.
Sweat
Sweat glands are used to regulate the temperature and dispose of waste by removing water, sodium salts, and nitrogenous wastes (such as urea) onto the skin surface. The main electrolytes of sweat are sodium and chloride, although the amount is small enough to make hypotonic sweats on the skin surface. The eccrine sweat is clear, odorless, and consists of 98-99% water; it also contains NaCl, fatty acids, lactic acid, citric acid, ascorbic acid, urea, and uric acid. The pH ranges from 4 to 6.8. On the other hand, apocrine sweat has a pH of 6 to 7.5; containing water, protein, carbohydrate waste materials, lipids, and steroids. His sweat was oily, cloudy, thick, and initially odorless; it stinks on decomposition by bacteria. Because apocrine glands and sebaceous glands are exposed to hair follicles, apocrine sweat is mixed with sebum.
Mechanism
It was initially thought that both apocrine and eccrine sweat glands use merochrin secretion, in which the vesicles in the glands release sweat through exocytosis, leaving the whole cell intact. More recent research has revealed that apocrine glands release sweat in the hair follicles through apocrine secretions, in which parts of the cells are completely pinched, and destroyed later to remove sweat.
In the apocrine and ekrin sweat glands, sweat was originally produced in the glandular coil, where isotonic with blood plasma there. When the level of sweating is low, salt is conserved and reabsorbed by the glandular channel; high sweat levels, on the other hand, cause less salt reabsorption and allow more water to evaporate on the skin (via osmosis) to increase evaporative cooling.
The secretion of sweat occurs when the myoepithelial cell cells surrounding the secretory gland contract. Eccrine sweat increases the rate of bacterial growth and evaporates the odor of apocrine odor, reinforcing the last sharp odor.
Usually, only a number of sweat glands are actively producing sweat. When stimulation requires more sweating, more sweat glands are activated, with each one then producing more sweat.
Stimulation
Thermal
Both the ecocrine and apocrine sweat glands participate in thermal sweat (thermoregulator), which is directly controlled by the hypothalamus. Thermal sweating is stimulated by a combination of internal body temperature and average skin temperature. In the eccrine sweat glands, stimulation occurs through activation by acetylcholine, which binds muscarinic gland receptors.
Emotional
Emotional sweating is stimulated by stress, anxiety, fear, and pain; it is independent of room temperature. Acetylcholine acts on the eccrine glands and adrenaline in both the eccrine gland and apocrine to produce sweat. Emotional sweating can occur anywhere, although it is most noticeable on the palms, soles of the feet, and axillary regions. Sweating in the palms and soles of the feet is thought to have evolved as an escape reaction in mammals: it increases friction and prevents slipping when running or climbing in stressful situations.
Gustatory
Excessive sweating refers to the thermal sweat caused by food consumption. Increased metabolism caused by consumption raises the body temperature, which causes thermal sweat. Spicy and hot foods also cause mild sweats on the face, scalp and neck: capsaicin (a compound that makes the "hot" spicy food taste), binding to receptors in the mouth that detect warmth. The increased stimulation of these receptors induces thermoregulation response.
Antiperspirant
Unlike deodorants, which only reduce underarm odor without affecting body function, antiperspirants reduce eccrine and apocrine sweat. Antiperspirants, which are classified as drugs, cause the protein to precipitate and mechanically block the eccrine sweat channel (and sometimes apocrine). Metal salts found in antiperspirants alter keratin fibrils in the ducts; the channel then closes and forms a "horny plug". The main active ingredients in modern antiperspirants are aluminum chloride, aluminum chlorohydrate, aluminum zirconium chlorohydrate, and aluminum sulfate buffered.
In apocrine glands, antiperspirants also contain antibacterial agents such as trichlorocarbanilide, hexamethylene tetramine, and zinc ricinoleate. Salt is dissolved in ethanol and mixed with essential oils high in eugenol and thymol (such as thyme and clove oil). Antiperspirant also contains levomethamphetamine
Pathology
Sweat gland disease includes:
- Fox-Fordyce's Disease
- Apocrine sweat glands become inflamed, causing rash, itching, usually in the axillary and pubic areas.
- Frey's syndrome
- If the auriculotemporal nerve is damaged (most commonly as a result of Parotidectomy), excessive sweating can be produced at the back of the cheek area (just below the ear) in response to stimuli that cause saliva.
- Heatstroke
- When the eccrine glands become exhausted and can not sweat. Heatstroke can cause a fatal hyperpireksia (extreme increase in body temperature).
- Hyperhidrosis
- (also known as polyhidrosis or sudorrhea ) is a generalizable or localized redundant or localized sweating (focal hyperhidrosis); Focal hyperhidrosis occurs most often in the palms, soles of the feet, face, scalp and axilla. Hyperhidrosis is usually caused by emotional or heat stress, but it can also occur or with little or no stimulus. Local (or asymmetric) hyperhidrosis is said to be caused by problems in the sympathetic nervous system: nerve lesions or inflammation. Hyperhidrosis can also be caused by foot trenches or encephalitis.
- Milaria rubra
- Also called prickly heat . Milaria rubra is a rupture of sweat glands and sweat migration to other tissues. In hot environments, the skin's horn layer may expand due to sweat retention, blocking the channels of the eccrine sweat glands. The gland, still stimulated by high temperatures, keeps issuing. Sweat builds up in the duct, causing enough pressure to break the channel where it meets the epidermis. Sweat also passes from the channel to adjacent tissues (a process called milaria ). Hypohydrosis then follows milaria (postmiliarial hypohydrosis).
- Osmidrosis
- Often called bromhidrosis , especially in combination with hyperhidrosis. Osmohidrosis is an excessive odor of apocrine sweat glands (which are too active in the axilla). Osmidrosis is thought to be caused by changes in the structure of the apocrine glands rather than changes in bacteria that work on perspiration.
Tumor
Sweat gland tumors include:
Adenoliphia is a lipoma associated with an extract of the sweat glands.
As a sign of another disease
Source of the article : Wikipedia
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