The Six Primary Functions of the Skin - a brazilian reasons #0019
Keep your skin healthy. It’s our body’s largest organ and healthy skin reflects overall wellness. The skin has six primary functions that help maintain its homeostasis.
I. Protection
The skin consists of layers, each containing important elements that serve to protect the body against harm.
The Malpighian layer produces the skin’s pigmentation and protects it against the harmful effects of ultraviolet radiation. Darker skin provides greater protection against the effects of sun exposure, skin cancer being the most common and most dangerous.
The outermost layer [horny zone] protects the body against bacterial infections. The chemical reaction between perspiration [from sudoriferous glands] and oil [from sebaceous glands] on the skin’s surface produces an acid-like barrier preventing harmful bacteria from invading the skin. Note: this is not true of the groin and axillae area because high levels of perspiration are less acidic thus allowing bacterial growth.
Sebum from the oil glands also prevents the skin from drying and cracking which would make it easy for bacteria to breach the skin’s surface and enter the blood supply. When unwanted bacteria do manage to invade the skin, the skin welts or swells and the unwanted organisms are recognized by Langerhans’ cells in the skin which then alert the body to release its defenses to the infected areas.
Fat cells in the subcutaneous layer provide protection against trauma from hard blows to the body and it also serves as an energy source.
II. Heat Regulation
o maintain a healthy body temperature of 98.6° Fahrenheit (37° Celsius), the body adjusts using various mechanisms when changes in our environment occur, this includes evaporation, perspiration, radiation and insulation.
The skin perspires by producing moisture through secretions of the sudoriferous glands. The evaporation of this moisture has a cooling effect on the body.
The dilation/expansion of capillaries causes the reduction of body surface heat through radiation [skin gets flush]. The opposite effect is when capillaries constrict/contract slowing blood flow, thus preserving heat [skin gets a blueish tint].
A muscle fiber in the skin called the arrector pili is stimulated when the body is cold or experiences fear and raises the hairs on the skin’s surface trapping a layer of insulating air [skin look like it has goose bumps]. This muscle is part of the hair follicle unit. Sebum, also excreted from the hair follicle, keeps the hair lubricated, preventing it from becoming brittle and breaking off thus allowing it to continue to do its job. Finally, the lowest layer of the skin is fatty tissue which also serves as an effective insulator.
III. Secretion
The sudoriferous glands, also known as the sweat glands, are responsible for secreting waste substances. These glands, influenced by the sympathetic nervous system, are divided into two classes: apocrine glands and eccrine glands. The primary process of the sympathetic nervous system is to stimulate the body’s fight-or-flight response, but it is otherwise constant in maintaining the body’s homeostasis.
The apocrine sweat glands, found in the genital and axillae area, secrete water, salts, cellular waste and fatty substances onto the skin through the hair shafts during perspiration. When these substances reach the surface, they combine with bacteria on the skin and create body odor. These glands also excrete pheromones which play a role in sexual attraction.
The eccrine sweat glands are located all over the body, but in greatest density across the forehead, the palms of the hands and soles of the feet. They secrete water primarily, but they also secrete some salts, urea and other water-soluble substances.
IV. Excretion
The sebaceous glands, also known as the oil glands, are responsible for excreting an oily substance called sebum which helps maintain healthy skin. These glands, influenced by the endocrine system which controls the body’s hormones, are located all over the skin but have the greatest density on the scalp, the face’s T-zone and cheeks.
Sebum is secreted through the shafts of the hair follicle and serves to lubricate not only the hair, but also the skin’s surface. By helping to protect both the hair and skin, they can then go on to serve their other functions successfully.
V. Sensation
Nerve endings in the skin carry impulses to the brain that allow us to experience heat, cold, pleasure/touch, pressure, pain, and even an itch.
The touch and pain receptors lie closes to the surface to the skin while the pressure receptors live deepest, thus requiring more stimulation to register an impulse. The heat and cold receptors are nestled between the ones already mentioned.
Without these receptors, “Life would be less interesting and more dangerous.”
VI. Absorption
The skin can absorb oily substances, therefore certain creams can be applied topically and absorbed into the blood supply. Therefore, it’s critical to only apply pharmaceutical and cosmeceutical lotions and creams as directed, especially if you are pregnant or have special medical conditions. Note: the skin is not able to absorb water.
Absorption is also important in the synthesis of vitamin D which is needed to absorb calcium and promote bone growth. The skin absorbs vitamin D from the sun’s ultraviolet (UV) radiation. Although this is a vital process, it is just as vital to protect the skin from too much sun exposure because too much UV exposure can not only cause skin cancer, but sunburn as well. If the skin is damaged, it can’t perform all its important functions.
The Federal Drug Administration’s minimum recommendation for protection against these dangers is SPF 15, but the American Academy of Dermatology recommends using SPF 30 or higher. Reference our post on the protective function of the skin.
Related Links:
sources:
“IBEC Study Guide”, American Electrology Association
“Electrolysis, Thermolysis and the Blend: The principles and Practice of Permanent Hair Removal”, Arthur Hinkel and Richard Lind.
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