Presentation is loading. Please wait.

Presentation is loading. Please wait.

Chapter 16 – digestive system

Similar presentations

Presentation on theme: "Chapter 16 – digestive system"— Presentation transcript:

1 Chapter 16 – digestive system
Major components: mouth, esophagus, stomach, intestines, liver, gallbladder, and pancreas Major functions: mechanical and chemical breakdown of food, absorption of nutrients and elimination of wastes

2 Histology of the digestive system
Four tissue layers (tunics): 1. Mucosa – innermost tunic – mucus epithelium, lamina propria, muscularis mucosa 2. Submucosa – thick layer of loose connective tissue 3. Muscularis – inner layer of circular smooth muscle and outer layer of longitudial smooth muscle 4. Serosa or adventitia – connective tissue layer

3 Structures: Oral cavity: mouth – bounded by lips and cheeks and contains teeth and tongue Muscles – (lips) – orbicularis oris, buccinator, tongue, frenulum - (function – mastication)

4 teeth 32 teeth in normal adult mouth Located in mandible and maxilla
Incisors, canines, premolars, molars See diagram page 452 Permanent vs. deciduous teeth Structure: crown, neck, root, pulp cavity, pulp, dentin, enamel, cementum, alveoli, gingiva, periodontal ligaments, periodontal membrane

5 Palate and tonsils Palate – 2 parts: 1. Hard palate 2. Soft palate
Uvula Tonsils – lateral, posterior walls of the oral cavity

6 Salivary glands See diagram on pg. 453 Three pairs – 1. parotid
2.Submandibular 3.sublingual

7 pharynx Nasopharynx Oropharynx laryngopharynx

8 esophagus Muscular tube – extends from pharynx to stomach
About 10 inches (25 cm) Passes through diaphragm Upper and lower esophageal sphincters Lined with mucous glands

9 Stomach Cardiac opening Cardiac region Fundus Body Greater curvature
Lesser curvature Pyloric opening (sphincter) Pyloric region

10 Stomach, continued Gastric pits Gastric glands Mucous cells
Endocrine cells Pepsinogen/pepsin rugae

11 Small intestine About 6 meters long (almost 20 ft)
3 sections: duodenum, jejunum, ileum Duodenum – about 12 inches, bile duct and pancreatic duct empty into it Duodenum has : circular folds, villi and microvilli to increase surface area

12 Small intestine, cont’d
Jejunum and ileum are similar in structure to duodenum, but diameter and numbers of villi, microvilli and circular folds decreases as you progress the length of the small intestine Ileocecal junction, sphincter and valve are found at the junction between the ileum and the large intestine

13 liver Weighs about 3 pounds Right upper quadrant of abdomen
2 blood sources Ducts transport bile to gall bladder

14 pancreas Pancreatic islets Insulin production

15 Large intestine Cecum Colon Rectum Anal canal

16 Colon 1.5 m long Ascending Transverse Descending Sigmoid Crypts

17 peritoneum Serous membranes Visceral peritoneum Parietal peritoneum
Mesenteries Lesser/greater omentum Retroperitoneal organs

18 Physiology of digestive system
Oral cavity, pharynx and esophagus Saliva – salivary amylase Mucin Mastication Deglutition Voluntary phase Bolus

19 Swallowing, contd Pharyngeal phase Epitglottis Esophageal phase
Peristaltic waves

20 Stomach Secretions – chyme Mucus Hydrochloric acid Pepsiogen Pepsin
Intrinsic factor gastrin

21 Regulation of stomach secretions
Cephalic phase Gastric phase Intestinal phase Secretin

22 Movement in the stomach
Mixing waves Peristaltic waves

23 Small intestine Peptidases Disaccharidases
Movement – segmental contractions, peristaltic contractions absorption

24 liver Digestive, excretory,stores and processes nutrients, synthesizes molecules, detoxifies Bile/bile salts

25 pancreas Trypsin Pancreatic amylase Lipases Nucleases insulin

26 Large intestine Feces Defecation Mass movements

27 Digestion, absorption, transport
Carbohydrates – mono, di and poly saccharides Lipids – triacylglycerol, saturated and unsaturated fats Proteins – pepsin, trypsin, peptidases and amino acids

28 Water and minerals 9 L of water enters digestive tract per day
1.5 of those in food and drink 7.5 L from digestive secretions

Download ppt "Chapter 16 – digestive system"

Similar presentations

Ads by Google