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Digestive System. Chapter 24. Functions. Layers. 1. Mucosa – lamina propria – 2. Submucosa – CT w/ bl vess. and nerves. Layers. 3. Muscularis externa– circ/long layers of smooth muscle 4. Serosa. Movement. Peristalsis – controlled by muscularis externa
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Digestive System Chapter 24
Layers 1. Mucosa – lamina propria – 2. Submucosa – CT w/ bl vess. and nerves
Layers 3. Muscularis externa– circ/long layers of smooth muscle 4. Serosa
Movement • Peristalsis – controlled by muscularis externa • Waves of contractions - move bolus along length of tract • Segmentation – small/large intestines
Control • Neural Mechanisms • Hormonal • Local
Peritoneum • Serous membrane that lines the abdominal cavity • Supports organs • Allows passage for bl. vess, nerves, etc • 2 layers • Visceral – covers organs • Parietal – lines cavity, lubricates • Layers connected by mesenteries
Oral Cavity Mouth 1. Tongue • Frenulum 2. Uvula
Oral Cavity Salivary Glands – exocrine glands w/ ducts, secrete amylase 1. Sublingal 2. Submandibular 3. Parotid
Oral Cavity Teeth • Crown • Neck • Root Composition: • Enamel • Dentin • Pulp - CT
Oral Cavity Teeth – mammals = 2 sets • Baby, deciduous milk • 20 teeth • Permanent • 32
Pharynx • Passage for food, liquid, air • st. sq ET
Esophagus • Collapsible • ~12” long • Esophageal hiatus
Stomach • Hollow • 3 layers of muscles • Rugae – • 3 functions: • Churns/liquefies food – chyme • Lining • Mucosa – secrete alkaline mucus • Parietal cells – HCl • Chief cells – pepsinogen • G cells – gastrin
Small Intestine • Digestion/absorption • Begins - • Ends - • Villi - • secretes – • 3 sections: • Duodenum • Jejunum – most absorption • Ileum
Pancreas • Retroperitoneal • Exocrine gland • Pancreatic juice - duodenum
Liver • Largest visceral organ • Secretes bile • Collects blood from intestines
Large Intestine • Colon • Large lumen • Functions • Sections • Ascending • Transverse • Descending • Sigmoid • Rectum • Anus