INTEGUMENTARY SYSTEM

The integumentary system contains skin, shell, feathers, nails, claws and hair. The system's function is to protect against disease, get rid of waste, keep the body temperature constant and to prevent dehydration. Skin is made of two layers. The outer layer is called the epidermis and the inner layer is called dermis. The epidermis is mostly dead cells and the dermis consists of living cells and special structures like nerves, muscles, hair, glands and blood. Nails and are made of keratin. They protect ends of fingers and toes. Nails grow about 1mm per week and throughout our lives. They're good indicators of health. Hair protects and insulate the body. Hair's produced by hair follicles. Skin glands release sweat and oil. They release excess water, salts, and urea. This helps regulate body temperature. Oil glands on the face and hair conceal sebum. Sebum prevents water loss, lubricates and softens the skin and hair. Acne results from oil glands clogging up due to a lot of sebum. 

An advantage of the integumentary system is protection. Animals that have shell have a good protection since shells are hard. Hair's beneficial because it helps maintain body temperature and also homeostasis. Since skin is the outer layer, it usually prevents germs and dirt. I think mitosis is a big factor since it helps with growth and repair. We can sense the feeling of things with skin. I used to think sweat wasn't really beneficial until I found out that we sweat because it helps us cool down.  

A disadvantage for this system is tiny insects attach to hair which can cause a disease. People shouldn't be out in the sun too much without protection like sun block. Our skin's prone to drying and burning. Skin isn't hard so it's easily to scrape or cut ourselves. Acne's the result of clogged oil glands. People usually get blackheads because their pores are clogged. 

Sources:    

http://bio1152.nicerweb.com/Locked/media/ch43/integumentary.html  

http://www.cyh.com/HealthTopics/HealthTopicDetailsKids.aspx?p=335&np=152&id=1766