1. Chapter 24
The Digestive System

2. Functions of the Digestive System
Ingest food
Digest food
Absorb nutrients
Eliminate indigestible waste

3. Digestive anatomy overview

4. Organization of the Digestive organs
Alimentary Canal
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
Anus
Accessory organs
Teeth
Tongue
Salivary glands
Gall bladder
Liver
Pancreas

5. The Digestive Process Ingestion Propulsion Mechanical Digestion
Chemical Digestion
Absorption
Defecation

6. Motility vs. Mixing
The difference between peristalsis and segmentation:
Peristalsis moves food along the tract. Segmentation is mixing and part of the mechanical digestion process.

7. Daddy, what does “retroperitoneal” mean?

8. This is your basic alimentary tract structure.

9. The oral cavity and pharynx

10. Say “ahhh”…

11. Road map of the tongue

12. Salivary glands

13. Human dental formula: Baby teeth

14. Human dental formula: Permanent teeth

15. Anatomy of a Tooth

16. The Stomach

17. Gastroesophageal junction
Stomach
Esophagus
Stratified squamous epithelium
Simple columnar epithelium

18. Gastric histology

19. Stimulus and control of gastric activity

20. HCl secretion

21. The stately process of gastric emptying

22. Control mechanisms of gastric contractions

23. The duodenum, gall bladder and pancreas

24. Histology of the small intestine
Adaptation for absorption

25. Duodenal mucosa Villi Goblet cells Crypts of Lieberkuhn!
Duodenal glands

26. Brunner’s (duodenal) glands
You only find us here,
In the duodenum!
Brunner’s (duodenal) glands

27. Absorption of Nutrients
Nearly all occurs in the small intestine.
80% of the electrolytes and virtually all food
Most nutrients are absorbed by active transport.
Glucose, amino acids, & nucleic acids are absorbed by secondary active transport with sodium.
Iron and calcium require transport proteins (ferritin) or cofactors (vitamin D).
Anions follow Na+.
Vitamins -
Fat soluble (A, D, E & K) vitamins are carried with micelles. Much of the K is absorbed in the colon.
Water soluble vitamins diffuse with the exception of B12, which requires intrinsic factor.

28. Crypts of Lieberkuhn!
Paneth cells

29. The Liver

30. Hormonal regulation of bile release

31. Exocrine tissues of the pancreas

32. Pancreas: Acinar cells

33. Activation of pancreatic proteases in the duodenum

34. Regulatory mechanisms for release of pancreatic juice

35. Anatomy of the large intestine

36. The Colon
Look at all those goblet cells!

37. The rectum and anus

38. The peritoneum

39. The Defecation reflex

40. Location of mesentary: The lesser omentum

41. Location of mesentary: The greater omentum

42. Chemical Digestion
Carbohydrates & proteins

43. Chemical Digestion
Lipids & Nucleic acids

44. Protein digestion in the small intestine

45. Bile salts emulsify fats

46. Absorption of lipid
Dietary fats are absorbed into the “lacteals” of the lymphatic system before being transferred to the circulatory system.

47. Lacteals