The mouth, consists of 2 regions, the vestibule and the oral cavity proper. The vestibule is the area between the teeth, lips and cheeks. The oral cavity is bounded at the sides and in front by the alveolar process (containing the teeth) and at the back by the isthmus of the fauces. Its roof is formed by hard palate at the front, and a soft palate at the back. The uvula projects downwards from the middle of the soft palate at its back. The floor is formed by the mylohyoid muscles and is occupied mainly by the tongue. A mucous membrane – the oral mucosa, lines the sides and under surface of the tongue to the gums, lining the inner aspect of the jaw (mandible). It receives the secretions from the submandibular and sublingual salivary glands.