Human Skin (image) University of California - San Diego Caption A magnification of the four distinct strata of human skin. At the top is the stratum corneum consisting of several layers of flat, dead, waterproof keratinocytes -- the outer layer of skin cells. Beneath the stratum corneum are the strata granulosum, spinosum and basale. It is in the stratum basale that resident stem cells differentiate to provide new cells and renew the skin. Below the stratum basale is the dermis, a collagen rich tissue that cushions the body. Credit UC San Diego School of Medicine Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.