Lecture 29Outline of Last Lecture I. Introduction to the Digestive SystemOutline of Current LectureI. The Digestive Systema. The MouthCurrent Lecturea. What is the vestibule of the mouth?i. The slit between the cheeks and teethb. Know the structure and functions of the parts of a tooth: enamel, dentin, pulp, cementum, periodontal membrane.i. Enamel: outer layer of the tooth, absorbs compression of chewing, no cells, only calcium-phosphateii. Dentin: mineralized material, bone-like but harderiii. Pulp: connective tissue proper, contains the nerves and vessels of the tooth iv. Cementum: thin layer of bone on the outside of the root, anchors coarse bundlesof collagen from the periodontal membranev. Periodontal membrane: dense connective tissue containing many thick collagen fibers, connect the tooth to the bone of the socketc. Why do many people get gingivitis, periodontal disease, and then lose their teeth as they grow older? i. Disease begins when a layer of bacteria-filled plaque builds up around the neck of the teeth; this irritates the gums, causes the gum to pull away from the tooth, and becomes a gum infection, the infection spreads to and destroys the periodontal ligament itself so the teeth fall outd. Why should you floss between your teeth? i. Removes the plaque, preventing gingivitis and tooth losse. Know the different classes of teeth, the role of each class in chewing, and the dental formula.i. Classes of Teeth:1. Incisors (nipping off pieces of food)2. Canine (piercing and cutting)3. Premolars (grasping and grinding)4. Molars (grinding)ii. Dental formula: on each side, right and left= 2:1:2:3f. What function does the tongue perform that demand it to be so movable and to contain so much muscle?i. Manipulates food during chewingii. Shape the food into a bolusiii. Moves food to back into pharynxiv. speechg. Tell the shape, function, and location of each type of papilla on the tongue surface.i. Filiform papillae: pointed, so tongue can grip food BIOL_315 1nd Editionii. Fungiform papillae: more sparsely dispersed than filiformiii. Vallate papillae: largest, V-shape in back 1/3 of tongue, only about a dozen of them, h. Which papillae have taste buds?i. Fungiform and vallate papillaei. What is the function of the hard palate? Of the soft palate?i. Hard palate: anterior 2/3, made of boneii. Soft palate: posterior 1/3, muscular, mobile flap, lifts up to close off the oropharynx from the nasopharynxj. What type of epithelium lines the oral cavity as well as most of the pharynx and esophagus?i. Stratified squamous epitheliumk. What kinds of glands make up salivary glands (simple or compound, tubular or acinar)?i. Compound tubuloacinar glandsl. Name the 3 large, paired salivary glands and tell their precise locations.i. Parotid gland: on the massester muscle, anterior to the earii. Submandibular gland: internal to the body of the mandible iii. Sublingual gland: inferior to the tonguem. In salivary glands, tell the function of serous cells and mucous cells? i. Mucous cells secrete mucous component of salivaii. Serous cells secrete the enzyme componentn. What is the pharynx, and where are its three parts located (oral, nasal, and laryngeal pharynx)?i. Pharynx: muscular, throat-part of the digestive tubeii. Nasopharynx- posterior to the nasal canaliii. Oropharynx- posterior to the oral cavityiv. Laryngopharynx- posterior to the larynxo. What are the pharyngeal constrictor muscles, and what do they do?i. Circular sheets of skeletal muscleii. These muscles contract one after another to squeeze food down to the esophagusp. What is the fauces?i. Where the oropharynx borders the mouthq. Define tonsils, know their histological structure and their function.i. Organs of the immune system in the pharynxii. Thickenings of the inner lining of the pharynxiii. Gather bacteria and other foreign particles from swallowed food or inhaled air iv. At risk for infection but create many memory lymphocytesr. Name and locate all 4 sets of tonsils in the pharynx: which tonsils are in the nasopharynx and which are in the oropharnyx?i. Palatine tonsils (oro)ii. Lingual tonsil(oro)iii. Pharyngeal tonsil (naso)iv. Tubal tonsils