Skin – Understanding Integumentary Systems

by Desiree Lotz September 29, 2014

SKIN

Skin – Understanding Integumentary Systems includes knowing its definition:

“(from Latin, integumentum, a covering <integere, to cover < in-, in, upon + tegere, to cover) a natural outer covering of the body or of a plant, including skin, shell, hide, husk or rind.”*

(* Webster’s New World Dictionary, Third College Edition, 1991.)

Skin is a living organ system that protects the human body from external scrapes and water loss. Skin also comprises parts of the body’s integumentary system network, including the hair, nails and some glands.

a multi-layered structure

At 12 to 15 percent of total human weight, skin is the largest body organ. Skin separates and protects a body’s inner parts from the outer environment organisms.

Tissue is a combination of cells and intercellular material charged with particular functions. Three layers make up human skin: the epidermis (epi-, on, over + dermis, Greek, derma, skin); the dermis; and the hypodermis (hypo-, Greek, hypo, under).

The epidermis barricades the body’s interior from the external environment, and does not contain blood vessels. Absorption of nutrients and internal/external balance maintenance are secondary functions. Epidermal cells produce a fibrous protein that waterproofs the skin and forms fingernails, keratin. Only the lining of skin on the inside of the mouth is non-waterproof.

The two-sectioned dermis is made up of different patterns, a pimpled layer and a web-like layer, and contains connective and muscular tissues, vessels, glands, follicles, hair roots, and sensory nerve endings.

Irregular connective tissue and ducted tissue arranged in a diversely bundled, two-layered, woven pattern make skin flexible and stretchable. This allows resistance to distortion, wrinkling and sagging. The dermis also houses blood vessel and nerve endings, as well as bases for skin color, hair and perspiration glands.

Hypodermis, the deepest and thickest of skin layers, is primarily fatty (adipose) tissue, which it accumulates and stores for use.

Fibrous proteins known as collagen and elastin, hold skin’s layers together, which permit most outer areas of the skin to move freely over the deeper layers.

a multi-functioning organ system

All body systems are synergistic in function. They maintain internal conditions essential to body function and survival in a process called homeostasis. Skin performs multiple roles in that process by waterproofing and cushioning those functions and deeper tissues from damage.

Skin also excretes wastes, regulates body temperature, and manufactures vitamin D by synthesis from sunlight, while protecting living tissues and organs from infectious organism invasions, dehydration, and abrupt changes in temperature.

Skin acts as a receptor for touch, pressure, pain, heat, and cold.

Skin’s sunburn protection, generation of vitamin D, and water, fat, and glucose storage, while it maintains body form, repairs minor injuries and offers UV ray protection make skin one of the human body’s most vital organs.

A recent discovery is that the body’s need for certain essential minerals often found more difficult to absorb as a body’s age progresses also comes under skin’s domain.