Blood, Sweat, and Tears: Human Anatomy

Skin: The Integumentary System

Functions                                                                                              Structures

1. Protection
The skins main function is containment and protection. It holds in organs, muscles, and bones, and keeps them protected by the thick, fleshy layer or skin.Skin is also important in not only protecting from external conditions that are physical problems (punctures or pressure), but also from the such things as heat and bacteria.
2. Synthesis of Vitamin D
A less obvious function of the skin is it's importance in synthesizing Vitamin D. Exposure to sunlight, specifically UV light, activates enzymes in skin that can synthesize Vitamin D, which is in turn important for the regulation of calcium and phosphorous in the body.
3. The Sense of Touch
Obviously, touch is an important function of skin since every part of your skin can expose you to feelings such as pain, heat, and pressure. In the layers of the integumentary system are networks of nerve cells that are sheltered by the skin which allow for these feelings.
4. Regulation of Body Temperature
The body maintains a very specific functioning temperature, and this needs to be constantly regulated. One of the most important regulators of temperature is the skin - specifically, sweat. Embedded in the integumentary system is not only a system of nerves, but sweat glands as well which allow for a function known as evaporative cooling. Specifically, as sweat evaporates from your body, the bonds that are broken take energy, in the form of heat, from your skin, which cools you down.
1. Epidermis
The epidermis is a very thin layer that serves mainly for a sort of "covering" of your body, which is why it's called the epidermis, or "outer skin". In the epidermis are two main sublayers: the Stratum Germinativum and the Stratum Corenum. The Stratum Germinativum is the thinner layer in the epidermis. It's main function is to replicate and renew itself for a constant layer of fresh protection. The Stratum Corneum is a little thicker and tougher, and serves the main job of protection.
2. Dermis
The dermis is really the "meat" of the integumentary system. It is right under the epidermal layer. In it are many important structures. There's a network of connective fibers that allow the skin to stretch. In it are also the network of nerves that allow for touch, the glands that allow for sweat, and hair follicles that allow for heat dispersal.
3. Subcutaneous Layer
This is the simplest layer. It's thick and fatty because this is where you store your fats. So, it's main functions are to store energy and to protect and insulate for both heat and dangerous conditions.