 The somatic cell from the Greek esosoma, meaning body or vegetal cell is any biological cell forming the body of an organism, that is, in a multicellular organism, any cell other than a gamete, germ cell, gametocyte or undifferentiated stem cell. In contrast, gametes are cells that fuse during sexual reproduction, germ cells are cells that give rise to gametes, and stem cells are cells that can divide through mitosis and differentiate into diverse specialized cell types. For example, in mammals, somatic cells make up all the internal organs, skin, bones, blood and connective tissue, while mammalian germ cells give rise to spermatozoa and ovate which fuse during fertilization to produce a cell called azirgoat, which divides and differentiates into the cells of an embryo. There are approximately 220 types of somatic cells in the human body. Theoretically, these cells are not germ cells. The source of gametes they never transmit to their descendants the mutations they have undergone. However, in sponges, non-differentiated somatic cells form the germline band. In that area, differentiated somatic cells are the source of the germline. The word somatic is derived from the Greek word soma, meaning body.