Skin Health

Sweat Glands

Human skin contains very many sweat glands, with secrete a watery fluid. These glands are especially numerous in hairless regions such as the palms and soles. Their ducts also form dimples, lined with epidermal cells, that descend into the dermis and connect with gland cells. They are well supplied with nerves and respond to excessive heat by the secretion of sweat, whose evaporation cools the skin. This in turn cools the capillary blood in the dermis. Stimulation by the para sympathetic nervous system also causes secretion the “cold sweat” of emotion.

The so called apocrine sweat glands found in the arm pits and the public region are attached to hair follicles and secrete an odorless milky fluid. Bacterial action on this fluid produces the distinctive body odor of an animal. The mammary glands, or breasts, are large, modified apocrine glands.

Skin functions.

The skin protects against mechanical injury and attack by bacteria, fungi, viruses, and parasites; its melamine blocks ultraviolet radiation. The skin controls body temperature in several ways, as well. Variable amounts of heat are lost through the skin by transfer from the dermis capillaries to the cooler epidermal cells, the amounts dependent on constriction or dilation of the dermal blood cells. Sweating cools the epidermis by evaporation.

The five distinct sensations arising from stimulation of skin nerves include touch, pain, heat, cold, and pressure. Other skin sensation, such as vibration, are composites of these basic sensations.

The skin responds to challenges to the immune system, as various allergy reactions show. Certain dermal cells release chemicals that cause changes in capillary diameter (redness and warmth) and permeably (swelling), and stimulation of nerve endings (pain)- all sign of inflammation.

posted by Margi @ 8:56 AM