The human body has three main levels of skin. Starting from the deepest, they are the hypodermis, the dermis, and the epidermis. The epidermis is the outmost layer of skin. Any external area of skin is considered the epidermis – for example, the face, arms, and scalp.
The epidermis’ main purpose is to keep foreign bacteria out while retaining important fluids, water especially. It is also what protects the organs, nerves, and circulatory system from physical damage.
While there are three main levels of skin, the epidermis itself can have up to five sublayers. The number of sublayers varies in location throughout the body. The five layers are:
Scalp skin is much thicker than skin found elsewhere on the body, and has an excellent blood supply. The scalp’s skin, muscle, and connective tissue are integrated together, which is what gives the scalp its extra elasticity. The scalp also has an abundance of sebaceous oil glands compared to elsewhere on the body. Sebaceous oil glands help keep the hair well-lubricated and allows for the hair shaft to make a smooth transition up the hair follicle and past the scalp.