1 All Physician Training licenses expire on August 31, 2015, are good for three years, and can only renew once (for a total of six years). 2  All Physician Assistant licenses expire on January 31 of even-numbered years.  All Anesthesiologist Assistant licenses expire on January 31 of even-numbered years.
The epidermis is the uppermost or epithelial layer of the skin. It acts as a physical barrier, preventing loss of water from the body, and preventing entry of substances and organisms into the body. Its thickness varies according to body site. The epidermis consists of stratified squamous epithelium.
Epidermis: The upper or outer layer of the two main layers of cells that make up the skin. The epidermis is mostly made up of flat, scale-like cells called squamous cells. Under the squamous cells are round cells called basal cells.The deepest part of the epidermis also contains melanocytes.These cells produce melanin, which gives the skin its color. The other main layer of the skin is the dermis, the inner layer of skin, that contains blood and lymph vessels, hair follicles, and glands.These glands produce sweat, which helps regulate body temperature, and sebum, an oily substance that helps keep the skin from drying out.he epidermis is mostly made up of flat, scale-like cells called squamous cells. Under the squamous cells are round cells called basal cells. The deepest part of the epidermis also contains melanocytes. These cells produce melanin, which gives the skin its color.