The skin is a vital organ that covers the entire outside of the body, forming a gigantic protective barrier against pollution, pathogens and injuries. Some skin details are:
The skin has up to “five” layers of ectodermal tissue
Stratum Corneum. Composed of dead cells called keratinocytes,
The functions of the skin are:
synthesis of vitamin D,
protection of vitamin B folates.
stores water, fat, and vitamin D,
plays a role in the immune system protecting us from disease
Some need to know facts:
The thickness of the skin varies considerably over all parts of the body, and between men and women and the young and the old.
There are different types of sweat cells
The average human skin cell is about 30 micrometers in diameter, but there are variants. A skin cell usually ranges from 25-40 micrometers (squared), depending on a variety of factors
The skin is the body’s second largest organ; covering the entire outside, it is about 2 mm thick and weighs an approximately 3-4 kilo.
The color, thickness and texture of skin vary over the body and for everybody. There are two general types of skin; thin and hairy, which is more prevalent on the body, and thick and hairless, which is found on parts of the body that are used heavily and endure a large amount of friction, like the palms of the hands or the soles of the feet.
The epidermis is the outermost layer of the three layers of skin. Its thickness depends on where it is located on the body. For example, it’s thinnest on the eyelids (half a millimeter). It’s thickest on the palms of the hands and soles of the feet (1.5 millimeters).
The skin contains many specialized cells and structures:
Basket cells surround the base of hair follicles and can sense pressure. They are evaluated when assessing overall nerve health and condition.
Blood vessels carry nutrients and oxygen-rich blood to the cells that make up the layers of skin and carry away waste products.
Hair Erector Muscle (Arrector Pili Muscle)
The arrector pili muscle is a muscle connected to each hair follicle and the skin. When it contracts it causes the hair to stand erect.
The hair follicle is a tube-shaped sheath that surrounds the part of the hair that is under the skin and nourishes the hair. It is located in the epidermis and the dermis.
The hair shaft is the part of the hair that is above the skin.
These cells attach themselves to antigens that invade damaged skin and alert the immune system to their presence.
A melanocyte is a cell that produces melanin, and is located in the basal layer of the epidermis.
Merkel cells are tactile cells of neuroectodermal origin located in the basal layer of the epidermis.
A pacinian corpuscle is a nerve receptor located in the subcutaneous fatty tissue that responds to pressure and vibration.
Sebaceous glands are small, sack-shaped glands which release an oily substance onto the hair follicle that coats and protects the hair shaft from becoming brittle. These glands are located in the dermis.
These nerves sense and transmit heat, pain, and other noxious sensations. When they are not functioning properly sensations such as numbness, pins-and-needles, pain, tingling, or burning may be felt. When evaluating a skin biopsy, total number, contiguity, diameter, branching, swelling, and overall health of the sensory nerves are assessed.
The stratum corneum is outermost layer of the epidermis, and is comprised of dead skin cells. It protects the living cells beneath it by providing a tough barrier between the environment and the lower layers of the skin. The stratum corneum is useful for diagnosis because in some conditions it will become thinner than normal.
Sweat Gland (Sudoriferous Gland)
These glands are located in the epidermis and produce moisture (sweat) that is secreted through tiny ducts onto the surface of the skin (stratum corneum). When sweat evaporates, skin temperature is lowered.