Structure and Function
One of the most common question about the integumentary system has got to be the question that asks what the system is made of. There are several layers to this system and they each have their own function.
The hair is one of the external structures. It's purpose is to assist the skin in maintaining body temperature as well as proving some level of protection.
The nails are also found in the external area of the integumentary system. The nails serve to protect the skin underneath and to some point, to serve as tools for digging and self defense, though this may not be as necessary as it once was.
The skin is actually made up of several layers. The epidermis, dermis, hypodermis, glands and blood supply are all parts of the skin. the skin is actually the largest organ of the entire body. The outer layer, the epidermis is made up of 4 different types of cells. It is thinner than the dermis and is separated from the dermis by a membrane. The epidermis serves a the out layer that protects the layers underneath and plays an important role in maintaining homeostasis and processing vitamin D.
The dermis holds the glands, blood vessels and nerve endings. This is the area thought to be most responsive to touch, which explains why injuries like paper cuts may seem so much more painful than deeper cuts. This is also the area responsible for skin responses like goosebumps, which are caused when the smooth muscles in the epidermis contract to hold in heat, squeezing the contained hair follicles and causing the hairs to rise.
Below the dermis lies the hypodermis. This is actually the layer that holds the skin to the underlying muscles and bones. Here we also find the supply of blood vessels and arteries.
The fact that the skin covers the entire body demonstrates its use as a protective layer and method for maintaining homeostasis functions like body temperature. The skin keeps the internal structures warm and the sweat glands within the skin help to cool the body when it gets too hot. Oil glands secrete oil in order to keep the skin flexible and waterproof. Not only does the skin protect us from elements such s heat, cold and water, but it also serves as a layer of protection against germs and bacteria that would otherwise have the ability to reach our internal structure.