optic disc, the small blind spot on the surface of the retina, located about 3 mm to the nasal side of the macula. It is the point where the fibers of the retina leave the eye and become part of the optic nerve.
Adult stem cells are found in many organs and tissues, including the skin. In fact, human skin is the largest repository of adult stem cells in the body. Skin stem cells reside in the basal layer of the epidermis where they remain dormant until they are activated by tissue injury or disease. 1.
Cells involved in skin cancer. Skin cancer begins in your skin's top layer â the epidermis. The epidermis is a thin layer that provides a protective cover of skin cells that your body continually sheds.The epidermis contains three main types of cells: 1  Squamous cells lie just below the outer surface and function as the skin's inner lining. Basal cells, which produce new skin cells, sit beneath the squamous cells. 2  Melanocytes â which produce melanin, the pigment that gives skin its normal color â are located in the lower part of your epidermis. 3  Melanocytes produce more melanin when you're in the sun to help protect the deeper layers of your skin.