Integumentary System (Skin)
What Can You Observe About Skin? Look at the skin on your arms and hands. What does your skin do for your body?
Using a hand lens, examine the skin on your hand. Look for pores and hairs on both the palm and back of your hand. What Can You Observe About Skin?
Place a plastic glove on your hand. After five minutes, remove the glove. Then examine the skin on your hand with the lens. What Can You Observe About Skin?
Think It Over Compare your hand before and after wearing the glove. What happened to the skin when you wore the glove? Why did this happen?
Skin The Body’s Largest Organ Includes: - Skin - Hair - Nails
Functions of the Skin - 7 major functions
Functions of the Skin 1. Covers the body
Functions of the Skin 2. Prevents the loss of water
3. Protects the body from infection and injury
4. Helps to regulate body temperature Functions of the Skin
4. Regulation of Body Temperature Blood Vessels expand and constrict - Increased blood flow releases more heat Sweat Glands - Skin has about 3 million - Releases sweat onto skin which has a cooling effect
Functions of the Skin 5. Gets rid of waste (sweat)
5. Gets rid of Wastes Sweat - Water - Sodium Chloride (salt) - Urea
6. Receives information from the environment Function of the Skin
6. Sensory Response Nerve cells in the skin detect and relay information about: - temperature - pressure - pain
Function of the Skin 7. Produces vitamin D
7. Formation of Vitamin D Produced in the epidermis Produced when UV light is present Vitamin D allows your body to absorb calcium
Skin Structure
2 Layers Epidermis Dermis
Epidermis Outermost Layer Made of dead skin cells New cells are constantly being made to replace the ones that are rubbed off Contains Melanin
Epidermis Outermost Layer Made of dead skin cells New cells are constantly being made to replace the ones that are rubbed off Contains Melanin
Melanin Pigment that gives your skin color Melanin increases in the presence of UV radiation Protects against UV damage
Dermis “True Skin” Layer below the epidermis Thicker than the epidermis Made of living cells Contains - blood vessels - nerves - sebaceous (oil) glands - sweat glands - hair follicles
Fatty Tissue Layer Below the dermis Insulates the body “Hypodermis”