1. Palate
Hard palate – anterior portion of mouth’s roof; formed by maxillae and palatine bones
Soft palate – posterior portion of mouth's roof; formed by two muscular arches:
Palatoglossal arch - extends from palate to tongue anterior to palatine tonsils
Palatopharyngeal arch - extends from palate to pharyngeal wall posterior to palatine tonsil

3. Figure 24.5 Structures of the mouth (oral cavity)

4. Salivary Glands General Saliva Functions:
Keeps the oral and pharyngeal mucous membranes moist.
Lubricates and dissolves food.
Starts carbohydrate chemical digestion.
Most saliva is secreted by salivary glands.
Some saliva comes from buccal glands in the mucous membrane that lines the mouth.
Minor salivary glands include labial, buccal, lingual and palatal glands which make a small contribution to saliva.

5. Salivary Glands Outside the mouth  ducts  oral cavity
Parotid glands - below ear, over masseter; parotid ducts open into vestibule beside 2nd maxillary molar.
Submandibular glands - under mandible; submandibular ducts open lateral to lingual frenulum
Sublingual glands - floor of mouth deep to tongue; lesser sublingual ducts open into floor of mouth

6. Figure 24.6 The three major salivary glands – parotid, sublingual, and submandibular

7. Salivary Glands Salivary gland cells are organized into acini.
Acini: small saclike cavities (clusters) in a gland surrounded by secretory cells.
Serous acini - secrete a watery fluid
Mucous acini - secrete a slimy, mucus secretion
Parotid glands – serous acini only
Submandibular glands – mostly serous acini and a few mucous acini
Sublingual glands - mostly mucous acini and a few serous acini

8. Figure 24.6b Histology of the submandibular gland

9. Composition and Functions of Saliva
99.5% water
0.5% solutes (salts, gases, mucous, ions, enzymes, lysozyme, IgA)
Functions:
Lubricate food for easier swallowing
Dissolve food for tasting
Moistens mucous membranes
Bicarbonate ions buffer acidic foods
Salivary amylase begins chemical digestion of starch (maltose)
Lysozyme  antibacterial
IgA  1st line of defense

10. Salivation The secretion of saliva. Salivation is under ANS control
Moistens mucous membranes
Assists speech
Almost all salivary components are reabsorbed
Dehydration – conserve water by not producing saliva

11. Salivation Increase salivation Sight, smell, sounds, thoughts/memory.
Tongue stimulation  taste buds
Salivatory nuclei in brainstem increase salivation
Parasympathetic nerve impulses stimulate saliva
Facial (VII) and glossopharyngeal (IX) nerves.
Stop salivation
Sympathetic nerves inhibit salivation

12. Tongue Composed of skeletal muscle covered with mucous membrane.
Forms oral cavity’s floor.
Participates in chewing, swallowing, and speech.
Glands on tongue’s dorsum secrete lingual lipase

13. Tongue Lingual frenulum - attaches tongue to mouth’s floor Tongue-tied
Ankyloglossia
Abnormally short frenulum
Speech impediment
Can be surgically repaired

14. Tongue Papillae cover upper surface (dorsum) and sides.
Projections of lamina propria
Some contain taste buds

15. Figure 11.7 Muscles that Move the Tongue - FYI

16. Teeth Project into the mouth
Alveolar processes of mandible and maxilla
Covered by gingivae

17. Teeth Fibrous connective tissue Anchor Shock absorber
Adapted for mechanical digestion.
A typical tooth consists of crown, neck, and root.
Composed primarily of dentin, which encloses the crown’s pulp cavity the roots’ root canals.
Root’s dentin is covered by cementum
Cementum attaches root to periodontal ligament
Fibrous connective tissue
Anchor
Shock absorber

18. Figure 24.7 A typical tooth and surrounding structures
Talk about the four things highlighted as those haven’t been mentioned yet through notes.

19. Tooth Types Incisors – chisel shaped; cutting
Cuspids (canines) – pointed; tearing
Premolars – bicuspid; crushing and grinding
Molars – four cusps; crushing and grinding

20. Dentition There are two sets of teeth in an individual’s lifetime:
Deciduous (primary) teeth
20 teeth that start erupting at 6 months
Permanent (secondary) teeth
32 teeth that erupt between 6 and 12 years of age

21. Figure 24.8 Deciduous (primary) dentition and times of eruptions

22. Figure 24.8b Permanent (secondary) dentition and times of eruptions

23. Digestion in the Mouth Mechanical digestion (mastication or chewing)
Breaks into pieces
Mixes with saliva  bolus
Chemical digestion
Amylase
Begins starch digestion at pH of 6.5 or 7.0 found in mouth
When bolus & enzymes hit the pH of 2.5 (gastric juices), hydrolysis ceases
Lingual lipase
Secreted by glands in tongue
Begins breakdown of triglycerides into fatty acids and glycerol once it reaches the acidic pH in the stomach

25. PHARYNX

26. Pharynx “Throat” – but don’t call it that…
Figures 23.2 / 24.10
Pharynx
“Throat” – but don’t call it that…
Funnel-shaped tube extending from internal nares to the esophagus and larynx
Skeletal muscle lined by mucous membrane.
3 parts:
Nasopharynx – only respiratory fnc
Oropharynx – digestive and respiratory fnc
Laryngopharynx – digestive and respiratory fnc

27. Figure The pharynx

28. Pharynx Deglutition or swallowing is facilitated by saliva and mucus
Starts when bolus is pushed into the oropharynx
Sensory nerves send signals to deglutition center in brainstem
Soft palate is lifted, epiglottis is bent
Ingested food  mouth  oropharynx  laryngopharynx  muscular contractions  esophagus  stomach

29. ESOPHAGUS

30. Esophagus Secrete mucus and transport food to the stomach.
Figure 24.1
Esophagus
Secrete mucus and transport food to the stomach.
Collapsible muscular tube = flexible
In front of vertebrae
Posterior to trachea
Posterior to the heart
Connects pharynx to stomach
Pierces diaphragm at hiatus