Apocrine sweat gland

Source: Wikipedia, the free encyclopedia.
Apocrine sweat gland
Details
PrecursorPrimary epithelial germ[4]
SystemIntegumentary system[2]
NerveAdrenergic nerves[3]
Identifiers
Latinglandula sudorifera apocrina[1]
MeSHD001050
THH3.12.00.3.03002
FMA59155
Anatomical terminology

An apocrine sweat gland (

eccrine sweat glands which cover the whole body.[9]

Most non-primate mammals, however, have apocrine sweat glands over the greater part of their body.[8] Domestic animals such as dogs and cats have apocrine glands at each hair follicle and even in their urinary system, but eccrine glands only in foot pads and snout. Their apocrine glands, like those in humans, produce an odorless, oily, opaque secretion[10] that gains its characteristic odor upon bacterial decomposition.[11] Eccrine glands on their paws increase friction and prevent them from slipping when fleeing from danger.[12]

Structure

The apocrine gland is made up of a glomerulus of secretory tubules and an excretory duct that opens into a hair follicle;[13] on occasion, an excretory duct opens to the skin surface next to the hair.[14] The gland is large and spongy, located in the subcutaneous fat deep in the dermis,[9][15] and has a larger overall structure and lumen diameter than the eccrine sweat gland.[16][8] The secretory tubules of apocrine glands are single layered, but unlike the eccrine secretory tubules, contain only a single type of ductal epithelial cell,[17] varying in diameter according to their location, and sometimes branching off into multiple ducts. The tubules are wrapped in myoepithelial cells, which are more developed than in their eccrine gland counterparts.[18][19]

Sweating

In hoofed animals and

warning signal.[10][21][22] Being sensitive to adrenaline, apocrine sweat glands are involved in emotional sweating in humans (induced by anxiety, stress, fear, sexual stimulation, and pain).[21]

In a five-month-old human fetus, apocrine glands are distributed all over the body; after a few weeks, they exist in only restricted areas,[9] including the armpits and external genitalia.[8] They are inactive until stimulated by hormonal changes in puberty.[21]

Mechanism

The apocrine gland secretes an oily fluid with

sebum, as sebaceous glands open into the same hair follicle.[23] Unlike eccrine sweat glands, which secrete continuously, the apocrine glands secrete in periodic spurts.[20]

Apocrine sweat glands were originally thought to use only apocrine secretion: vesicles pinch off from the secretory cells, then degrade in the secretory lumen, releasing their product.[24] More recent research has also shown that merocrine secretion takes place.[25]

Myoepithelial cells form a smooth muscle lining around the secretory cells; when the muscles contract, they squeeze the secretory ducts and push out the accumulated fluid into the hair follicle.

NaCl.[27] The sweat only attains its characteristic odor upon being degraded by bacteria, which releases volatile odor molecules.[23] More bacteria (especially corynebacteria) leads to stronger odor. The presence of axillary hair also makes the odor even more pungent, as secretions, debris, keratin, and bacteria accumulate on the hairs.[15]

Prevalence

Non-primate mammals usually have apocrine sweat glands over most of their bodies.

equines than in other groups.[28] Skunks, on the other hand, use the glands to release a secretion that acts as a powerful defense mechanism.[20]

The "axillary organs", limited regions with equal numbers of apocrine and eccrine sweat glands, only exist in humans, gorillas, and chimpanzees.[9] In humans, the apocrine glands in this region are the most developed (with the most complex glomeruli).[18] Men have more apocrine sweat glands than women in all axillary regions.[29][30]

There is currently no evidence that any sweat glands vary substantially by racial group, with most studies claiming to find variation being subject to methodological flaws.[31]

See also

References

Citations

  1. ^ H3.12.00.3.03002
  2. ^ Neas, John F. "Development of the Integumentary System". In Martini, Frederic H.; Timmons, Michael J.; Tallitsch, Bob (eds.). Embryology Atlas (4th ed.). Benjamin Cumings. Archived from the original on 8 August 2012. Retrieved 17 December 2012.
  3. ^ a b Krstic 2004, p. 466.
  4. ^ Tsai 2006, p. 496.
  5. .
  6. .
  7. .
  8. ^ a b c d e Kurosumi, Shibasaki & Ito 1984, p. 255.
  9. ^
    S2CID 28234765
    .
  10. ^ a b "Cutaneous Apocrine Gland Tumors". The Merck Veterinary Manual. Merck Sharp & Dohme Corp. Archived from the original on 2016-03-04.
  11. ^ Eroschenko 2008, pp. 228–229.
  12. ^ Wilke et al. 2007, p. 170.
  13. ^ Kurosumi, Shibasaki & Ito 1984, pp. 255–256.
  14. ^ Tsai 2006, pp. 496–497.
  15. ^ a b Tsai 2006, p. 497.
  16. ^ Krstic 2004, p. 468.
  17. .
  18. ^ a b Kurosumi, Shibasaki & Ito 1984, p. 256.
  19. ^ Eroschenko 2008, p. 226.
  20. ^ .
  21. ^ a b c Wilke et al. 2007, p. 171.
  22. .
  23. ^ a b Wilke et al. 2007, p. 175.
  24. ^ "sweat gland". Miller-Keane Encyclopedia & Dictionary of Medicine, Nursing, and Allied Health (7th ed.). Saunders. 2003. Retrieved 18 December 2012.
  25. .
  26. .
  27. .
  28. ^ Caceci, Thomas. "Integument I: Skin". VM8054 Veterinary Histology Laboratory Exercises. Virginia–Maryland Regional College of Veterinary Medicine. Archived from the original on 13 May 2015. Retrieved 19 December 2012.
  29. ^ Wilke et al. 2007, p. 174.
  30. ^ Stoddart 1990, p. 60.
  31. PMID 11807469
    .

Sources

External links