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U5: Mouth/Teeth/etc
Digestive System Part II: Mouth, Teeth, Salivary Glands
| Question | Answer |
|---|---|
| Mouth/Oral Cavity/Buccal cavity | lined w/ stratified squamous epithelium; anterior formed by labia, lateral walls formed by cheeks holds tongue, teeth, etc. |
| Labia | form the anterior border of mouth; core and bulk consists of orbicularis oris skeletal muscle |
| Gingivae/gingiva | gums; surround bases of teeth |
| Vestibule | slit between the teeth & lips and teeth & cheeks; when using a toothbrush, it is in the vestibule |
| Palate | forms the roof of the mouth; consists of hard palate anteriorly and soft palate posteriorly |
| Hard palate | forms the anterior portion of the roof of the mouth |
| Soft palate | forms the posterior portion of the roof of the mouth; posterior inferior tip is the uvula |
| Uvula | posterior, inferior tip of soft palate; rises to close off the nasopharynx during swallowing |
| Cheeks | form lateral borders of mouth; core and bulk consist of skeletal muscle called the buccinator muscle |
| Tongue | made of skeletal muscle tissue; forms floor of oral cavity; mixes food w/saliva forming bolus; moves posteriorly to push bolus into oropharynx; undersurface fold is the lingual frenulum; posterior portion is lingual tonsil, superiorly covered by papillae |
| Bolus | compact mass of food and saliva formed by tongue movements; pushed into oropharynx by tongue |
| Lingual frenulum | fold of mucous membrane/mucosa on undersurface of tongue; both secures tongue to floor of the mouth and limits its posterior movements |
| Lingual tonsil | covers most posterior part of tongue which lies in the oropharynx |
| Papillae/papilla | peg-like projections on superior surface of tongue; taste buds are located on the sides of some of them |
| Teeth | provide for mastication; lie in alveoli in alveolar margins of the mandible and maxilla; two sets during life—deciduous and permanent; classified by shape and function; full set will have 32 |
| Mastication | chewing; function of teeth |
| Alveolar margins of the mandible and maxilla | where teeth are located/lie |
| Deciduous/baby/milk teeth | first set of teeth; emerge by about 2 yrs of age and totals 20 teeth; as permanent teeth enlarge/develop, roots of this set of teeth are reabsorbed causing teeth to fall out between 6 & 12 y.o. |
| Permanent teeth | set of teeth usually completely erupted by the end of adolescence (except wisdom teeth); full set will be 32 teeth w/ arrangement in each half of upper and lower jaws-2 incisors, 1 canine, 2 premolars, 3 molars |
| 2 incisors, 1 canine, 2 premolars, 3 molars | arrangement of teeth in each half of upper and lower jaws |
| Impacted teeth | teeth abnormally embedded in jawbone that push on roots of other teeth; cause pressure and pain and must be removed; wisdom teeth most commonly fall into this category |
| Superior alveolar nerves | innervate upper teeth; branches of the maxillary division of the trigeminal nerve (cranial nerve V) |
| Inferior alveolar nerves | innervate the lower teeth; branches of the mandibular division of the trigeminal nerve |
| Two regions of a tooth | crown and root |
| Crown | region of the tooth above the gum/gingiva; covered in layer of enamel |
| Enamel | layer covering tooth on crown; hardest substance in the body |
| Root | region of tooth below the gum/gingiva; embedded in the jawbone |
| Dentin | layer of bone-like material forming bulk of tooth, both crown and root; underlies enamel in crown |
| Cementum | covers external surface of root; calcified connective tissue, attached to the periodontal ligament |
| Periodontal ligament | cementum attaches to it; helps anchor the tooth in a bony socket (alveolus) of jaw bone |
| Pulp cavity | space that occupies the center of the tooth; contents collectively known as pulp, includes nerves and blood vessels |
| Pulp | contents of pulp cavity; consists of nerves and blood vessels; can become infected when a tooth has a crack or deep cavity |
| Root canal | where the pulp cavity extends into the root; narrow; provides a route for blood vessels and nerves to enter and exit the pulp cavity |
| Root canal therapy | procedure performed if pulp is infected due to crack/deep cavity; all pulp is drilled out, pulp cavity is sterilized and filled with artificial, inert material and then tooth is capped. |
| Dental cavities/caries | result from gradual demineralization of enamel & dentin by bacterial action; decay begins w/ accumulation of dental plaque, film of sugar, bacteria and debris; metabolism of trapped sugar by bacteria produces acids which dissolve calcium salts from teeth |
| Salivary glands | produce saliva (mixture of water, mucus, enzymes); enzymes begin digestion; some are scattered in mucosa of mouth, but 3 pairs of large extrinsic lie outside oral cavity and connect via ducts-parotid, submandibular, sublingual |
| Parotid salivary gland | largest of the salivary glands; lies anterior to ear, between masseter muscle and skin; mumps will cause the gland to swell |
| Mumps | a viral infection whose symptoms include inflammation and swelling of the parotid salivary gland |
| Submandibular salivary gland | salivary gland on medial surface of mandibular body just anterior to junction w/ mandibular ramus |
| Sublingual salivary gland | salivary gland in floor of oral cavity, under the tongue |