Published 21 Dec 2016

The largest and most underappreciated organ that has such wide-ranging functions is the integumentary system. This system accounts for approximately sixteen percent of a human’s total body weight, and it acts as the body’s first line of defense against constant attacks by microorganisms, sunlight and environmental chemicals and hazards (Martini 154).

The two major components include the superficial epithelium (epidermis) and dermis, which is comprised of underlying connective tissues (Martini 154). The primary functions of the skin and underlying layers are protection of impact, abrasions and fluid loss. Its excretion of salts, water, organic waste productions, as well as regulation of body temperature are very important, also (Martini 154). The integumentary system is involved in the synthesis of vitamin D3, which is important in normal calcium metabolism. It is vital in the detection of touch, pressure, temperature and pain, and relaying such information to the nervous system (Martini 155).

The epidermis is made up of a stratified squamous epithelium that provides a c substantial amount of protection that keeps microorganisms outside the body. The epidermis is avascular (Martini 155). These cells depend on nutrient diffusion and oxygen from capillaries within the dermis. The epidermis encompasses two layers: thin and thick. Thin skin layer cells contain the protein keratin and cover the majority of the body’s surface. This layer is as thick as a plastic sandwich bag (.08mm). Thick skin is found on the soles of the feet and palms. This epidermis layers is slightly thicker at .5mm, or the thickness of a standard paper towel (Martini 155).

Carotene and melanin are the two epidermal pigments that are the basis of skin color. Carotene is a orange-yellowish pigment that normally accumulates in the epidermal cells. This is found in orange vegetables like carrots and squash. Eating high quantities of these vegetables can cause an overabundance, which will turn the inpiduals orange (Martini 158). Carotene can be converted into vitamin A ā€“ required for both maintenance of the epithelia and synthesis of photoreceptors in the eye (Martini 158).

Melanin is a yellow-brown, or black, pigment produced in melanocytes. These cells are deep within epithelial cells. Melanin protects the epidermis and dermis from the harmful ultraviolet rays the sunlight (Martini 159).

The second main component of the integumentary system is the dermis. The dermis lies between the epidermis and the subcutaneous layer. The subsections of the dermis are the papillary layer and the reticular layer. The papillary layer contains the capillaries, sensory neurons and lymphatics that supply the skin’s surface (Martini 161). The reticular layer is a vast network of dense irregular connective tissue containing both elastic fibers and collagen (Martini 161).

The presence of collagen and elastic fibers provide the skin with strength and elasticity. Collagen fibers are strong and resist stretching. However, collagen bends and twists easily. Elastic fibers allow stretching and recoil to its original length (Martini 162). They both provide flexibility but prevent damage to the tissue (Martini 162).

The subcutaneous layers are connective tissue fibers that are located in the reticular layer and intergraded into the hypodermis. This layer is not part of the integument, but is an intricate part of stabilizing the position of the skin in relation to underlying tissues, like other organs, skeletal muscle, all while offering independent movement (Martini 163). The subcutaneous layer is comprised of areolar and adipose tissue and is elastic. Arteries and veins are only located in the superficial region, which contain a great deal of blood that will go to general circulation if blood vessels contact (Martini 163).

The adipose tissue acts as a shock absorption system. Dispersion of the subcutaneous adipose changes through an inpidual’s adulthood in response to sex hormones. In early life, the adipose deposits are common in the neck, lower back and buttocks. As adulthood reaches in women it accumulates in the breasts, hips and thighs. High amounts in both sexes are present in the abdominal region (Martini 164).

The skin is the largest and most visible organ that can make diagnosis of abnormalities easily noticeable. General conditions of the skin can be important, such as colored appearances, changes in flexibility, elasticity, dryness and sensitivity of the skin.

For instance, yellowish skin and mucous membranes may indicate jaundice. The liver is unable to excrete a digestive compound called bile. The yellow pigment builds up in the bodily fluids. Moreover, in advanced stages, jaundice can cause the skin and sclera to turn yellow (Martini 159). Complications can very but can cause life-threatening liver failure. A liver function test is needed to determine severity.

Even though jaundice is not a direct skin disorder the physical appearance indicates this disease, and a physician can properly diagnosis this problem (National Library of Medicine & National Institutes of Health 2008).

With age, the supply of blood to the dermis becomes diminished. This effect causes the skin to become cool and stimulate thermoreceptors (Martini 173). This response can make an inpidual cool in a warm room. Then again, the circulation to the skin lessens causing an inability to lose body heat. The sweat glands do not function properly and cannot cool the inpidual down like it should. This is contributed to the less active merocine sweat glands. Overexertion and exposure to very hot climates will cause the body to reach hazardous temperatures (Martini 173).

As aging process progress, the integumentary system declines in overall function. This skin’s structure is thin and cells are not as tightly packed leaving the body susceptible for infection. As the skin thins when inpiduals age germinative cell activity greatly deteriorate leaving them prone to both injury and infections (Martini 172).

For example, the number of Langerhans cell can decrease as much as fifty percent of levels seen at maturity, roughly 21 years of age (Martini 173). These Langerhans are cells rise from the bone marrow to the dermis. These cells are important in the immune system (Wrenn 2003).

Another disease that is linked to the immune system and integumentary system is psoriasis. It can affect anyone, but is more common throughout adulthood (Penn State University). This disease causes dry, itchy, sore patches of skin with silvery scales. Common problem areas included the elbows, knees, face and feet. T-cells are a type of white blood cells that usually aid the body against infections, but are put to action by error (National Library of Medicine & National Institutes of Health 2008).

These T-cells become so overly active that it interferes with the adult inpidual’s immune response. It leads to fast skin cell turnover. The skin cells deep within rise to the surface. The process takes about a month in inpiduals without psoriasis ā€“ it only takes days with psoriasis. Common treatments include topical creams that relieve swelling and skin turnover. Physicians can administer medicine through a shot if the psoriasis is severe and is called systemic treatment (National Library of Medicine & National Institutes of Health 2008).

Melanocyte activity declines with age and light-skinned inpiduals become pale and more sensitive to the sun’s harmful UV rays. This increases the risk of sunburns and skin cancer. Skin cancer is an uncontrollable growth of skin cells that can spread to other tissues and organs (National Library of Medicine & National Institutes of Health 2008).

Nonmelanoma is the most common skin cancer after the age of 40 years of age. This could be contributed to the lack of melanocyte activity. Nonmelanoma is a direct result of ultraviolet exposure ((National Library of Medicine & National Institutes of Health 2008). Sunburns are a result of exposure of ultraviolet rays that exceeds the ability of the body’s protective pigment. Skin swelling can occur. An older adult or elderly inpidual can become affected quickly due to the lack of melanin. This could be combated with the proper sunscreen to help protect the skin from the sun (National Library of Medicine & National Institutes of Health 2008).

Almost anyone will have benign tumors of the skin, and moles are the common example. However, skin cancer is much more dangerous and the most common form of cancer (Martini 160). Two-thirds of all skin cancers appear in region that are chronically exposed to UV light. Malignant melanomas are extremely dangerous and involve cancerous melanocytes and growth and spread rapidly. It is very important for early detection. Once treated survival rate of five years or more is ninety-nine percent. If detected late and extensive metastasis occurs the prognosis is a survival rate drops fourteen percent (Martini 160).

Elderly inpiduals are affected because they become more sensitive to UV rays and are fair-skinned. Research concludes that fair-skinned inpiduals are most susceptible to all forms of skin cancer (Martini 160). This can be avoided by not being exposed to the sun midday when the sunlight is the most dangerous. Always use sunscreen with a SPF 20-30. The organic chemicals in sunscreen help scatter and reflect the suns UV rays. Protect clothing is also a protect option (Martini 160).

Increased sun exposure can increase the risk of skin cancers and sunburns, but also can unravel the interconnected fibers that provide the skins structure and elasticity. The collagen and elastic fibers break down and decrease in size, thus becoming weaker and less flexible. Sagging and winkling of the skin will occur (Martini 173). Although, sagging and winkles may be inevitable the degree can be reduced by proper skin care and protection from sunlight.

The production of vitamin D declines approximately seventy-five percent. The result is a reduced absorption of calcium and phosphate. This will eventually lead to muscle weakness and bone strength and density (Martini 173). This in return will lead to possible bone fractures and other muscular or skeletal injury. If the skin cannot produce vitamin D a supplemental form may be administered in order to maintain bone development (Martini 161).

The integumentary system is a complex network that offers protection from the elements, impact and microorganisms. As everyone ages and obvious physical and physiological changes begin to occur, most are unavoidable. It is important to take care of and protect the skin early in life to help lessen the severity of most conditions like skin cancer. Immune failure that cause skin disorders like psoriasis should be handled immediately with proper medical care. The integumentary system literally keeps every inpidual’s lives together and should be treated with the utmost care.


  • Integumentary System. 2008. Penn State University. Handout pg. 54.
  • Martini, Frederic H., Ph.D., et al. Fundamentals of Anatomy and Physiology. Pearson, Benjamin and Cummings Pushlishing, 2006. Seventh Edition. Pgs. 150-170.
  • Skin Cancer. 21 March 2008. National Library of Medicine and National Institute of Health. Updated 20 February 2008
  • Psoriasis. 21 March 2008. National Library of Medicine and National Institute of Health. Updated 11 March 2008.
  • Wrenn, Eric A. Integumentary System. 22 March 2008. University of Pittsburg.
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