Hair
Whats the stuff that's on your head? Your arms? Your legs? Its hair! There are more than 100,000 hair follicles on your scalp. Hair protects the scalp from sunlight. It grows really slow, at a rate of .08 inches in a week for three to five years. Just like the skin, the more melanin in the hair, the darker it is. When people get older, their hair gets whiter. White hair comes from lack of pigmentation. Hair is tubes of dead cells that are filled with Keratin. It plays an important part in keeping the dust out of eyes and nose. |
Skin
Skin is the largest organ in the body. Skin helps get rid of wastes through sweat. Have you ever seen someone with really dark or light skin? That's because of their levels of melanin. Melanin is a chemical in the skin. The more melanin in skin, the darker it will be. Skin also helps regualte body temperature using sweat. When sweat evaporates, heat leaves the body. There are 2 levels of skin, Dermis and Epidermis. Epidermis the layer of skin on top and Dermis is the thicker, lower layer. |
Nails
Nails cover and protect the upper, distal ends of fingers and toes. They help with gripping objects. Nails are made up of dead cells and are packed with Keratin. Ever wonder how fast your nails grow? Nails grow at a slow rate of .2 inches in a month. The nail is attached to the skin on three sides and has a free edge. The free edge is the one people tend to bite off. |
The Integumentary System
The Integumentary system is a system made up of hair, skin, and nails. It's function is to protect the tissue that lies beneath them and it helps to matain homeostasis.