Integumentary System

Function of the skin Cover and protects from germs, dehydration and injury It is the first line of defense from illness Regulates body temperature Manufactures Vitamin D Site of many nerve endings Temporary storage of glucose, fat, water and salt Protects from UV radiation Can absorb chemical substances

Skin Layers Epidermis Dermis Hypodermis

Epidermis Outermost layer of skin, has no blood in it all dead skin cells, every minute of the day we lose about 30,000-40,000 dead skin cells of the surface of the skin Protection layer of skin Melanin is produced here. This is the pigment that gives our skin its color. The more melanin the darker the color. Sunlight stimulates melanin production

Dermis True skin and is very vascular and contains pores Thicker inner layer of skin Matted masses of connective tissue, elastic fibers, nerve endings, muscles, hair follicles, oil and sweat glands Contains sensory cell - hot, cold, pain and pressure Blood vessels regulate the body temp by expanding or contracting Sebaceous glands lubricate, protect and waterproof the skin Sweat glands cool and protect the skin Follicles is where hair grows. Hair that you see is made of dead cells

Hypodermis Also known as the subcutaneous layer Loose connective tissue and FAT, half of the body’s stored fat is here Connects the integumentary system to the muscles Insulates Absorbs shock

One Square Centimeter of Skin Contains 3,000,000 cells 10 hairs 1 yard of blood vessels 4 yards of nerves 700 sweat glands 200 nerve endings to record pain 3000 sensory cells at the end of the nerve fibers

Fun facts about the skin It is the larges of the body’s organs Thickest skin is on the palms of your hands and soles of your feet and the thinnest is the eyelid A large part of the dust in your house is actually dead skin cells