Eccrine gland ( ; from ekrrinein "secrete", sometimes called merochrin gland ) is the major sweat gland from the human body, is found in almost all skin, with the highest density in the palms of the hands and soles of the feet, then in the head, but much less on the trunk and extremities. In lower mammals, they are relatively rare especially in areas without hair such as footwear. They reach the peak of its development in humans, where they can reach 200-400/cmÃ,² from the surface of the skin. They produce substances that are clear, odorless, sweat, mainly composed of water.
The eccrine gland consists of an intraepidermal spiral channel, "acrosyringium"; ductal dermal, consisting of straight and circular parts; and a secretory tubule, circling deep within the dermis or hypodermis. The eccrine gland opens through the pores of perspiration. The rolled portion is formed by two concentric layers of columnar or cuboid epithelial cells. Epithelial cells are diverted by the myoepithelial cells. Myoepithelial cells support secretory epithelial cells. Eccrine gland channels are formed by two layers of cuboid epithelial cells.
The eccrine glands are active in thermoregulation by providing cooling from the evaporation of water from sweat secreted by the glands on the surface of the body and the sweating caused by emotion (anxiety, fear, stress, and pain). The white sediment in colorless eccrine secretion is caused by evaporation which increases the salt concentration.
The smell of sweat is due to bacterial activity in the secretion of apocrine sweat glands, the very different types of sweat glands found in human skin.
The eccrine gland is innervated by the sympathetic nervous system, mainly by the cholinergic fibers whose discharge is modified primarily by changes in body temperature in the (core temperature), but by the adrenergic fibers as well. The glands on the palms and soles of the feet do not respond to temperature but secrete in times of emotional stress.
Video Eccrine sweat gland
Secretions
The secretion of the eccrine gland is sterile, aqueous electrolyte solution with the main components of bicarbonate, potassium, and sodium chloride (NaCl), and other small components such as glucose, pyruvate, lactate, cytokines, immunoglobulins, antimicrobial peptides (eg, dermcidin), and more.
With respect to plasma and extracellular fluids, the ion concentration of Na is much lower in sweat (~ 40 mM in sweat versus ~ 150 mM in plasma and extracellular fluid). Initially, in the eccrine gland, sweat has a high concentration of Na ion. Ion Na is reabsorbed into the tissue through the epithelial sodium channel (ENaC) located in the apical membrane of the cell that forms the eccrine gland ducts (see Fig. 9 and Fig. 10 of the reference). This Na ion retention reduces the loss of Na during the sweat process. Patients with systemic pseudohypoaldosteronism syndrome carrying mutations in the ENaC subunit gene have salty sweat because they can not reabsorb salt in perspiration. In these patients, the concentration of Na ions can be greatly increased (up to 180 mmol/L).
In people with hyperhidrosis, sweat glands (especially eccrine glands) overreact to stimuli and are generally just too active, producing more sweat than usual. Similarly, cystic fibrosis patients also produce salty sweat. But in this case, the problem lies with the CFTR chloride transporter which is also located in the apical membrane of the eccrine gland ducts.
Dermcidin is a newly isolated antimicrobial peptide produced by eccrine sweat glands.
Maps Eccrine sweat gland
References
External links
- 3D visualization video of the human human gland channel
Source of the article : Wikipedia
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