Integumentary System Scratching the Surface

Our Largest Organ… Major functions include: –Protection – prevents chemical and physical injury –Sensory response –Vitamin D formation –Regulate body temp. –Rids the body of waste Major functions include: –Protection – prevents chemical and physical injury –Sensory response –Vitamin D formation –Regulate body temp. –Rids the body of waste

Contains 3 layers Epidermis Dermis Subcutaneous (fatty) layer Contains 3 layers Epidermis Dermis Subcutaneous (fatty) layer

Epidermis The thinnest, outermost layer Epidermis cells are constantly being replaced Produces the chemical melanin –A pigment that protects your skin and gives it color. –Production increases when exposed to UV rays and skin becomes darker –Darker skin = greater protection The thinnest, outermost layer Epidermis cells are constantly being replaced Produces the chemical melanin –A pigment that protects your skin and gives it color. –Production increases when exposed to UV rays and skin becomes darker –Darker skin = greater protection

Dermis and Subcutaneous Dermis –Thicker layer located directly below the epidermis –Contains blood vessels, nerves, muscles, oil and sweat glands Subcutaneous –Below the dermis –Fatty region that insulates the body –Where most fat is deposited when we gain wait. Dermis –Thicker layer located directly below the epidermis –Contains blood vessels, nerves, muscles, oil and sweat glands Subcutaneous –Below the dermis –Fatty region that insulates the body –Where most fat is deposited when we gain wait.

Vitamin D Formation Small amounts are produced in the presence of UV light. Vitamin D helps your body absorb calcium into your blood from food in your digestive tract. Small amounts are produced in the presence of UV light. Vitamin D helps your body absorb calcium into your blood from food in your digestive tract.

Heat Exchange Blood vessels help release or hold heat –When they dilate (expand) blood flow increases and heat is released –When they constrict (shrink) blood flow decreases and less heat is released Blood vessels help release or hold heat –When they dilate (expand) blood flow increases and heat is released –When they constrict (shrink) blood flow decreases and less heat is released

Heat Exchange Sweat glands –When blood vessels dilate, pores open in the skin that lead to sweat glands –Perspiration moves out onto the skin, and heat transfers from the body to the sweat on the skin Sweat glands –When blood vessels dilate, pores open in the skin that lead to sweat glands –Perspiration moves out onto the skin, and heat transfers from the body to the sweat on the skin

Waste Exchange Sweat glands also release waste products produced by your cells –Water, salt, and other organic wastes If too much water and salt are released, you can become dehydrated Sweat glands also release waste products produced by your cells –Water, salt, and other organic wastes If too much water and salt are released, you can become dehydrated

Injury and Repair Bruises (contusions) –Tiny blood vessels under the skin burst –Red blood cells leak into the surrounding tissue –Hemoglobin from the red blood cells begins to breakdown into different pigments, giving bruises their different colors Broken down blood returns to bloodstream Bruises (contusions) –Tiny blood vessels under the skin burst –Red blood cells leak into the surrounding tissue –Hemoglobin from the red blood cells begins to breakdown into different pigments, giving bruises their different colors Broken down blood returns to bloodstream

Injury and Repair Cuts –Any tear in the skin –Blood clots and forms a scab –Surrounding cells fight off infection –Skin cells beneath the scab grow to fill the gap in the skin –Scars may result from thick tissue fibers if a cut is too deep. Cuts –Any tear in the skin –Blood clots and forms a scab –Surrounding cells fight off infection –Skin cells beneath the scab grow to fill the gap in the skin –Scars may result from thick tissue fibers if a cut is too deep.

Injury and Repair Skin grafts –Pieces of skin that are cut from one part of the body and moved to cover the injured area –Nearby blood vessels keep the grafted skin alive –Used when not enough skin cells are left Skin grafts –Pieces of skin that are cut from one part of the body and moved to cover the injured area –Nearby blood vessels keep the grafted skin alive –Used when not enough skin cells are left