The Human Body is an app, but it was originally made the old fashioned way, with cut-out paper. Made by studio Tiny Bop, each page is interactive and visually accessible. As described on their site:
Everything, from the bones and brain to cells and veins, is animated by particle physics in this interactive playscape. Children can poke, probe, and examine the skeletal, muscular, nervous, circulatory, respiratory, and digestive systems. Each app contains a recording tool so you and your child can ask questions, listen, and respond to each other.