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.
The epidermis is composed of the outermost layers of cells in the skin Epidermis is the outer layer of cells covering an organism, in  particular. Your epidermis is the outer layer of your skin. Anything that is not your skin.    Epidermis-- The uppermost layer of skin cells. The epidermis is the outer covering of a living thing or organism.