Therapeutic cloning involves the cloning of embryos for the production of stem cells. Therapeutic cloning extracts the nucleus from the somatic cell then inserts it into the egg from which the nucleus has previously been removed. The egg is now stimulated to divide and quickly forms a clump of cells called a blastocyst. This blastocyst has both an outer layer and an inner layer of cells and this is the inner layer. Cells from the inner cell mass are isolated and then used to create embryonic stem cell lines, which are infused into the patient where they are ideally integrated into the tissue, giving it structure and function.