Sweat gland
As sweat ( Latin parotid sudorifera ) special are glands of the skin called, which emit a watery discharge.
Your glandular tissue located in the dermis (dermis) and produces a secretion that of pores of the epidermis is excreted (epidermis). The eccrine sweat glands, which are typically numerous in humans, secrete a watery secretion in the form of sweat ( sudor ), which is mainly used for thermoregulation through evaporation cold .
In special body regions there are also scent glands , also called apocrine sweat glands , whose secretion contributes to the development of a special scent ( odor ). Both types of glands belong to the skin appendages .
Classification
The eccrine (merocrine) sweat glands (Latin: Glandulae sudoriferae merocrinae ) have a diameter of 0.4 mm and are surrounded by a thick basement membrane . They are located on the border between the skin and the subcutaneous tissue . These sweat glands have no relationship with the hair and are unevenly distributed throughout the body.
The apocrine sweat glands (Latin: Glandulae sudoriferae apocrinae ) are also called scent glands . They only occur in certain skin areas ( armpit , nipple , genital and perianal area ). Their glandular bodies are significantly larger and 3 to 5 mm in diameter. They lie in the subcutis (subcutaneous tissue ) and are closely related to the hair follicles in whose ducts they open. Apocrine sweat glands are formed in the 4th embryonic month, but do not function properly until puberty; secretion production is particularly activated by emotional stimuli (e.g. fear, excitement, anger).
Both types of sweat glands are innervated by the sympathetic nervous system, but not with the same neurotransmitter . The eccrine sweat glands have cholinergic receptors and the apocrine sweat glands have adrenergic receptors .
Function and distribution
Eccrine sweat glands
Eccrine sweat glands regulate the heat balance of the living being through the physical effect of evaporative cooling . In addition, sweat ensures the skin is supple and has the correct pH value , as sweat is slightly acidic. The sweat glands can take over a small part of the detoxification activity if the kidneys are not functioning properly. This is because the sweat, in addition to water and fatty acids, is made up of substances that have to be urinated, such as B. nitrogenous substances and table salt . Substances such as dermcidin with antibacterial protective properties are also secreted.
Overall, the human body has an extraordinarily high number of eccrine sweat glands (two to four million) compared to other mammals . The number varies depending on the body region. Sweat glands are particularly numerous on the soles of the feet, palms and forehead. Their occurrence is densest at 600 / cm² on the soles of the feet and least common at around 100 / cm² on the thigh.
Apocrine sweat glands
The so-called "apocrine sweat glands" or scent glands release other substances into the hair funnel in addition to pheromone - like fragrances , which are only converted into various odorous substances together with the sebum and under the action of skin bacteria . Unlike the so-called "eccrine sweat glands", scent glands are each bound to a hair follicle and restricted to certain parts of the body. Their secretion and that of the sebum glands as well as the respective bacterial flora of a skin region are largely responsible for the (natural) body odor and can also differentiate the odor of a body by region. Therefore, scent glands often play a not insignificant role in social and sexual behavior; they can also be used to mark territory (see Jacobson's organ ).
Examples of scent glands in particularly pronounced in animals have anal glands , anal sacs , the interdigital bag , Sternalorgan , Metatarsalbürsten , chin gland or Inguinaltasche that infants finding the mammary gland relieved.
Diseases of the sweat glands
- Adenoma (benign tumor)
- Anhidrosis (lack of perspiration)
- The Chromhidrosis is a very rare disease in which the patient is colored sweat secretes. Possible colors are, for example, green, blue and black. The cause has not yet been clarified, but it is suspected that the patient ingested metal particles with the food.
- Hyperhidrosis (excessive sweating)
- Bromhidrosis (excessive body odor)
literature
- Johannes Sobotta, Ulrich Welsch: Textbook histology. Cytology, histology, microscopic anatomy. 2nd Edition. Urban & Fischer, 2005, ISBN 3-437-42421-1 .
- H. Geyer: Specific skin glands. In: Franz-Viktor Salomon et al. (Hrsg.): Anatomie für die Tiermedizin. 2nd Edition. Enke, Stuttgart 2008, ISBN 978-3-8304-1075-1 , pp. 641-645.
- Peter Fritsch: Dermatology, Venereology. 2nd Edition. Springer, Berlin / Heidelberg / New York et al. 2004, ISBN 3-540-00332-0 , p. 28f.
- Detlev Drenckhahn, Wolfgang Zenker: Benninghoff Anatomie Volume 2. 15th edition. Urban & Schwarzenberg, Munich / Vienna / Baltimore 1993, ISBN 3-541-00255-7 , p. 809.
