Question

what protect underlying tissue from physical damage?

Answer 1

The epidermis provides protection to underlying tissues from physical damage, pathogens, and UV light.

The epidermis is the outer of the two main layers of skin, the inner layer being the dermis. It average about 0.10 mm thick and is much thinner than the dermis. The epidermis is thinnest on the eyelids 0.05 mm and thickest on the palms of the hands and soles of the feet ( 1.50mm). The epidermis covers almost the entire body surface. It is continuous with, but structurally distinct from, the mucous membranes that line the mouth, urethra, and vagina.

CELLS OF THE EPIDERMIS

There are several different types of cells in the epidermis. All of the cells are necessary for the important functions of the epidermis.

• The epidermis consistent mainly of stacks of keratin producing epithelial cells called Keratinocytes. These cells make up at least 90 percent of the epidermis. Near the top of the epidermis, these cells are also called squamous cells
• Another 8 % of epidermal cells are melanocytes. These cells produce the pigment melanin that protects the dermis from UV light.
• About 1%of epidermal cells are langerhans cells. These are immune system cells that detect and fight pathogens entering the skin.
• Less than 1 percent of epidermis cells are merkel cells, which respond to light touch and connect to nerve endings in the dermis.

LAYERS OF THE EPIDERMIS

• The epidermis in most part of the body consists of four distinct layers.
• A fifth layer occurs in the palms of the hands and soles of the feet, where the epidermis thicker than it is in the rest of the body.