And then we have the innermost cells, these brown cells that make up the endoderm germ layer. And each one of these germ layers gives rise to many different types of structures and organs. So let's begin by focusing on the ectoderm. So the cells of the ectoderm basically make up the outer portion of that developing embryo. And so there's no surprise that the ectoderm layer basically forms the outer portion of our body and that includes our skin, our integumentary system. So basically the outer layer of the skin, the epidermis of the skin, is formed by the ectoderm as well as all the accessory structures down inside our skin.