1. Chapter 24, part 2
The Digestive System

2. SECTION 24-2 The Oral Cavity

3. The mouth opens into the oral or buccal cavity
Its functions include:
Analysis of material before swallowing
Mechanical processing by the teeth, tongue, and palatal surfaces
Lubrication
Limited digestion

4. Oral cavity Lined by oral mucosa
Roof of cavity = hard and soft palates
Floor of cavity = tongue
Uvula guards opening to pharynx

5. Figure The Oral Cavity
Figure 24.6a, b

6. The tongue primary functions include: Mechanical processing
Assistance in chewing and swallowing
Sensory analysis by touch, temperature, and taste receptors

7. Tongue movements involve
Extrinsic and intrinsic tongue muscles
Innervated by the hypoglossal nerve

8. Salivary glands (three pairs)
Parotid, sublingual, and submandibular
Saliva
watery solution
electrolytes, buffers, glycoproteins, antibodies, enzymes
Functions include:
Lubrication, moistening, and dissolving
Initiation of digestion of complex carbohydrates
PLAY
Animation: Mastication Flythrough

9. Figure 24.7 The Salivary Glands
Figure 24.7a, b

10. Teeth Function in mastication of bolus Contact of occlusal surfaces
Contain three layers
Enamel covering crown
Dentin forms basic structure
Root coated with cementum
Periodontal ligaments hold teeth in alveoli

11. Eruption of teeth 20 primary teeth AKA deciduous teeth
32 teeth of secondary dentition

12. Figure Teeth
Figure 24.8a, b

13. Figure 24.9 Primary and Secondary Teeth
Figure 24.9a, b

14. SECTION The Pharynx

15. The pharynx Common passageway for food, liquids, and air
Lined with stratified squamous epithelium
Pharyngeal muscles assist in swallowing
Pharyngeal constrictor muscles
Palatal muscles

16. SECTION 24-4 The Esophagus

17. The esophagus
Carries solids and liquids from the pharynx to the stomach
Passes through esophageal hiatus in diaphragm
The wall of the esophagus contains mucosal, submucosal, and muscularis layers

18. Histology of the esophagus
Distinctive features of the esophageal wall include
Nonkeratinized, stratified squamous epithelium
Folded mucosa and submucosa
Mucous secretions by esophageal glands
A muscularis with both smooth and skeletal muscle portions
Lacks serosa
Anchored by an adventitia

19. Figure The Esophagus
Figure 24.10a-c

20. Swallowing (deglutition)
Buccal phase
Pharyngeal phase
Esophageal phase

21. Figure 24.11 The Swallowing Process
Figure 24.11a-h

22. SECTION The Stomach

23. Functions of the stomach
Bulk storage of undigested food
Mechanical breakdown of food
Disruption of chemical bonds via acids and enzymes
Production of intrinsic factor

24. Anatomy of the stomach Cardia – superior, medial portion
Fundus – portion superior to stomach-esophageal junction
Body – area between the fundus and the curve of the J
Pylorus – antrum and pyloric canal adjacent to the duodenum

25. Stomach anatomy Phloric Sphincter Guards exit from stomach Rugae
Ridges and folds in relaxed stomach

26. Figure The Stomach
Figure 24.12b