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 epithelium is a layer of cells-epithelial cells. They are highly specialised for selective secretion and absorption of ions and molecules. Epithelial cells line any surface that comes into contact with the external environment. So-the airways, the gut, the urinary tract, the cornea etc.tratified squamous epithelium is found in areas where layers of epithelial cells are likely to be sloughed off. Examples of simple squamous epithelium: 1  Endothelium-lines the circulatory system. 2  Mesothelium-lines the peritoneal (abdominal), pleural (lung) and pericardial (heart) cavites.