Structure & Function ofSkin

Unit I

Do Now Take Ten Minutes to describe what is the

purpose of skin

Structure and Function of the Skin

The skin1 is one of the largest organs in the body in surface area and weight. 

The skin consists of two layers: the epidermis and the dermis.

Beneath the dermis lies the hypodermis or subcutaneous fatty tissue.

Structure and Function of the Skin

Epidermis Epidermis-The epidermis is the outer layer

of skin. The thickness of the epidermis varies in different types of skin. It is the thinnest on the eyelids at .05 mm and the thickest on the palms and soles at 1.5 mm.

The epidermis contains 5 layers.

The top layer of the epidermis, the stratum corneum, is made of dead, flat skin cells that shed about every 2 weeks.

Epidermis (cont’d)

Dermis DermisThe dermis also varies in thickness

depending on the location of the skin. It is .3 mm on the eyelid and 3.0 mm on the back. The dermis is composed of three types of tissue that are present throughout - not in layers. The types of tissue are:

collagen

elastic tissue

reticular fibers

Dermis (cont’d)

Subcutaneous Tissue

The subcutaneous tissue is a layer of fat and connective tissue that houses larger blood vessels and nerves.

This layer is important is the regulation of temperature of the skin itself and the body.

The size of this layer varies throughout the body and from person to person.

Subcutaneous Tissue

Structure and Function of the Skin

The skin has three main functions: protection, regulation and sensation.

Protection The skin is an organ of protection. The

primary function of the skin is to act as a barrier.

The skin provides protection from: mechanical impacts and pressure, variations in temperature, micro-organisms, radiation and chemicals.

Skin Regulation The skin is an organ of regulation. The skin

regulates several aspects of physiology, including: body temperature via sweat and hair, and changes in peripheral circulation and fluid balance via sweat. It also acts as a reservoir for the synthesis of Vitamin D.

Skin Regulation The skin is an organ of sensation. The skin

contains an extensive network of nerve cells that detect and relay changes in the environment.

There are separate receptors for heat, cold, touch, and pain. Damage to these nerve cells is known as neuropathy, which results in a loss of sensation in the affected areas.

Patients with neuropathy may not feel pain when they suffer injury, increasing the risk of severe wounding or the worsening of an existing wound.

Tattoo’s Does tattoo ink penetrate down to the

dermis? Why or why not

Take two minutes and come up with explanation

Tatted Up From this image describe

the tattoo process. This should be one paragraph. Make sure you use the correct terms for describing the layers of skin.

EX- “The epidermis is the first layer of skin”

BAD EX- “The needle touches the first layer of skin”

Exit Slip What are the two layers of skin?

What lies beneath the dermis?

Which tissues are located in the dermis?