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.
Stem cells are derived from several sources in the body. They are found in mature body tissues, umbilical cord blood, fetal tissue, the placenta, and within embryos. Stem cells develop into tissues and organs in the body. In some cell types, such as skin tissue and brain tissue, they can also regenerate to aid in the replacement of damaged cells.