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Chapter 24, part 2 The Digestive System.

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Presentation on theme: "Chapter 24, part 2 The Digestive System."— Presentation transcript:

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

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