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 cellsâ value to researchers is that they can be induced into becoming specific tissue or organ cells. The cloning procedure works by combining a patient's body cell with an unfertilized egg cell from a donor. The patient's skin cell is inserted into the outer membrane of the egg cell and chemically induced to begin developing into a blastocyst. In the blastocyst, embryonic cells divide, producing a mass of stem cells. The stem cells can be induced to differentiate into different types of cells as needed (heart, nerve, muscle, etc.). These cells are genetically identical to the patient's own cells (that is, they are cloned).