Peristalsis is the rippling movements of the muscles to help the food travel along different parts of the alimentary canal.
Goblet cells protect the living cells of the alimentary canal from hard rough food and enzymes.
They make mucus. The mucus covers the inside of the alimentary canal with a slimy layer over which undigested food can easily glide. Also enzymes cannot get at living cells and harm them. Sphincter muscles are what control the outlet and inlet of food from the stomach to prevent blockages. They are rings of muscle, which can contract to squeeze the tube in and out of the stomach closed so that food stays inside the stomach while it is churned up with enzymes and hydrochloric acid.