1. The Integumentary System
Principles of Health Science
Unit 6:3

2. Intro-The Integumentary System
Integumentary means “skin” or “covering”
It is the largest organ in the body
The average person’s skin weighs 10 pounds and has a surface area of almost 20 square feet.
Consists of the skin, hair, nails, glands, and nerves
It sheds constantly 24/7 and are replaced by new skin cells.
Its main function is to act as a barrier to protect the body from the outside world, to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature.

3. 3 Main Layers of Skin Epidermis-outermost; sheds
Dermis-center; contain papillae
Hypodermis or subcutaneous layer; fatty part and connects to muscle

4. 7 Functions of the Skin Your skin performs the following functions:
Protection: from the sun’s UV rays, against invasion by infectious germs, prevents deeper tissues from drying out.
Sensory perception: the nerves in the skin help the body respond to pain, pressure, temperature, and touch.
Body Temperature regulation: Protects the body against abrupt changes in temperature
Storage: stores fat (adipose), water, vitamins and salts
Absorption: certain substances can be absorbed through the skin such as medications called transdermal medications.
Excretion: helps eliminate salt and excess water and heat through perspiration
Production: produces Vitamin D from the ultraviolet (UV) light striking the skin which is an essential vitamin necessary for the absorption of calcium from food and sun.

5. Temperature Regulation
Body temperature regulation
If too hot
Dermal blood vessels dilate
Vessels carry more blood to surface so heat can escape
If too cold
Dermal blood vessels constrict
Prevents heat from escaping

6. Skin Color
Human skin color is controlled by the interaction of 3 pigments: melanin, carotene, and hemoglobin. Melanin is a brown or black pigment produced by melanocytes to protect the skin from UV radiation and gives skin its tan or brown coloration and provides the color of brown or black hair. Melanin production increases as the skin is exposed to higher levels of UV light resulting in tanning of the skin. Carotene is another pigment present in the skin that produces a yellow or orange cast to the skin and is most noticeable in people with low levels of melanin. Hemoglobin is another pigment most noticeable in people with little melanin. It is the red pigment found in red blood cells, but can be seen through the layers of the skin as a light red or pink color.

7. Diseases and Abnormal Conditions (See pages 116-117)
The skin is an organ that is susceptible to disease and abnormalities.
Examples:
Cancer-malignant and benign
Dermatitis-inflammation of the skin caused by irritants
Athletes foot-contagious fungal infection of the feet
Eczema-inflammation skin disorder caused by an allergen or irritant and can be triggered by stress.
Psoriasis-white and flaky usually inherited (chronic)
Impetigo-contagious caused by strep infection
Ringworm-contagious fungal infection in skin and scalp

8. Vocabulary Follicles-a hollow tube that contains the root of the hair
Hair-helps protect the body and found everywhere except the bottoms of your feet and your palms. You have several million hair.
Nails-help protect your fingers and toes from injury. The nail will regrow only if the nail bed is not damaged.
Sudoriferous glands-are the “sweat glands”
found in the dermis
contain salt, water, and other body wastes that you perspire
Sebaceous glands-are the oil glands that open up with the hair follicles
They produce “sebum” that keeps the skin from drying out
It is an antifungal and antibacterial oil that helps prevent infections
If it becomes clogged then a pimple or a blackhead is formed.

9. Other Vocabulary Alopecia-baldness
Albino-the absence of color pigment of the skin
Jaundice-a yellow discoloration of the skin
Cyanosis-blue skin