Not only are the sensory cells on the skin formed from the exoderm but the lens of the eye and the cornea of the eye are also formed from the ectoderm. Now we also form the epithelium of the mouth and the anus from the ectoderm. The majority of the digestive system as we'll see in just a moment is actually formed from the endoderm layer. But the epithelium of the mouth and the anus are in fact formed from the actoderm germ layer. Now we also form the epithelium of the pituitary gland found in the brain as well as the penial gland. And that makes sense because these structures are found close to our nervous system inside our brain.