Sweat glands

What is Sweat Glands

Eccrine sweat glands are simple coiled tubular glands with a merocrine secretion. It is known as a merocrine cell which is the one where secretions from secretory cells are released via exocytosis into an epithelial duct or ducts. They then move onto a bodily surface or into the lumen.

Their total number ranges from two to four million. They can be found in almost all skin areas, including the human one. However, they are most prevalent on the soles, foreheads and axillae of the skin. Although there are no differences between males and women, Afro-Americans have them more frequently, possibly due to more environmental than genetic factors.

The acrosyringium” is an intraepidermal, spiral duct containing the “eccrine” and the dermal duct with a straight portion and a coiled section. There’s also a secretory duct, which is located deep within the dermis.

Eccrine glands secrete an electrolyte solution that is dilute and sterile. It contains primary components such as bicarbonate (K), sodium chloride (NaCl) and potassium. Other components such as glucose, pyruvate, lactate, cytokines, immunoglobulins, antimicrobial peptides, and many others are also secreted.

Functions of the sweat glands:

  • Thermoregulation: The body’s temperature increases the rate of perspiration. A portion of the body’s heat is used for the evaporation water contained in the sweat.
  • Excretion of Solutes: The body’s temperature increases the rate of perspiration. A portion of the body’s heat is used for the evaporation water contained in the sweat.
  • Contribution to The Formation of The Hydrolipidic Film: There is still some responsiveness to both the cholinergic as well as adrenergic stimuli. Cholinergic sweating is a biphasic process that involves initial hyperpolarization followed by secondary depolarization. This is mediated through the activation of calcium ion conductance and chloride. Cystic fibrosis transmembrane conductance regulator (GCI) is required for monophasic depolarization. Adrenergic secretion includes monophasic and cyclic fibrosis adrenergic secretion. Cystic fibrosis patients’ cells show no evidence of adrenergic release.

Vasoactive intestinal protein may also be involved in stimulating eccrine production.

Hyperhidrosis is possible by using the following connections:

  1. Cerebral cortex to the hypothalamus.
  2. Hypothalamus to the medulla.
  3. Fibers cross the medulla Oblongata to travel to and from the lateral horn.
  4. The lateral horn to sympathetic ganglia.
  5. Sympathetic ganglia to sweat glands as postganglionic C fibers.

The sympathetic fibers from the hypothalamus cross mostly at the pons level. However, most of the crossing takes place in the medulla. Alternate sweating may result in Horner’s syndrome, which is characterized by ipsilateral hyperhidrosis.

 

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