Effects of Aging on the Integumentary System

Effects of Aging on the Integumentary System

Damaged skin affects almost every body system. It leads to bone softening, impaired or accelerated metab-olism, failure of the cardiovascular system, changes in immune function, and many other outcomes. Intact skin can greatly improve quality of life in later years. It protects the muscles, improving body temperature reg-ulation and blood flow. Nervous system organs such as touch receptors are protected by intact skin. It also pro-tects endocrine organs, prevents fluid loss, regulates normal secretions, protects lymphatic organs to pre-vent edema, protects respiratory organs for adequate oxygen supply, protects digestive organs for nutrient absorption, protects urinary organs for proper excre-tion, and protects reproductive organ health.

The skin initially develops from either the embry-onic ectoderm (epidermis) or the mesoderm (dermis and hypodermis). The skin is mostly formed by the end of the 4th month of gestation. The fetus is covered with delicate colorless hairs (the lanugo coat) during months 5 and 6 of gestation, but this coat disappears by the 7th month, replaced by vellus hairs. At birth, the newborn’s skin is covered with vernix caseosa, a white substance that appears “cheese-like.” It is produced by the sebaceous glands to protect the skin while the infant is still inside the mother’s amnion. Small white spots appear on the forehead and nose called milia, which are accumulations in the sebaceous glands. They usually disappear by the 3rd week after birth. The skin thickens during infancy and childhood, with more subcutaneous fat being deposited. During adolescence, skin and hair both become oilier due to activation of the sebaceous glands. Acne may develop during this time, which usually subsides by early adulthood. The skin reaches its best appearance when a person is in his or her 20s and 30s. Later, when it shows the effects of abrasion, chemicals, sun, and wind, common condi-tions include scaling or dermatitis (skin inflammation). Atopic dermatitis or eczema is a genetic condition that is also exacerbated by environmental factors.

In older age, epidermal cells are replaced less quickly. The skin becomes thinner and is more suscep-tible to bruises and other injuries. It is less lubricated and often becomes dry and itchy. Clumping of elastic fibers occurs. There are less collagen fibers and they also become stiffer. Older people are unable to tolerate colder temperatures as well because their subcutaneous fat layer diminishes. Fat distribution becomes more sim-ilar between men and women because they have lower levels of sex hormones than earlier in life. Wrinkling occurs due to thinning of the epidermis and a decline of the protein elastin. Incidence of skin cancer is higher because of decreased amounts of melanocytes and den-dritic cells. Because they have less melanin than other people, fair-skinned and redheaded people usually show age-related changes more quickly. Hair thinning results by age 50, because active hair follicles are two-thirds less prevalent. The hair loses its luster, and the genes activate that trigger male pattern baldness and hair graying.

To slow skin aging, you should shield your skin from the aging UVA rays and the burning UVB rays of the sun. When protection from the sun occurs throughout life, aged skin will remain unwrinkled and unmarked, although it still thins and loses a certain amount of elasticity. Protective clothing and sunscreens or sunblocks of 15 (or higher) sun protec-tion factors (SPFs) are encouraged. Although a nice tan may be appealing early in life, sunlight eventually causes the skin to sag, wrinkle, and become marked with pigmented “liver spots.” UVA rays activate matrix metalloproteinase enzymes, degrading dermal compo-nents such as collagen. However, the skin aging pro-cess may be delayed by cleanliness, good nutrition, plenty of fluid consumption, and the drug tretinoin (Retin-A®). This agent is related to vitamin A and inhibits the matrix metalloproteinases. It is found in many skin creams designed to slow photoaging.

In most people, signs of aging generally appear by their late 40s. Signs of aging in the integumentary system include thinning, graying hair, dry hair and skin, thinning skin, sagging skin, bleeding within the skin, easier bruising, slower healing from injuries, and recurring infections. Body heat regulation var-ies because of atrophy of blood vessels, sweat glands, and subcutaneous fat. The skin may also show signs of yellowing, mottling, age spots, and wrinkling. The most serious condition affecting the skin during the aging process is skin cancer (discussed later). With age, germinative cell activity declines, Langerhans cells decrease, vitamin D₃ production decreases, melano-cytes decline, glandular activity declines, dermal blood supply reduces, and many hormones reduce in level.

1. What is the vernix caseosa that covers the skin of a newborn baby?

2. Why are elderly people less able to tolerate cold temperatures?

3. Why do skin wrinkles develop because of the aging process?