1. 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. This is your basic alimentary tract structure.

7. Sagittal view of abdominal viscera

8. Peristalsis
Figure 24–4

9. Segmentation Cycles of contraction: Churn and fragment bolus
mix contents with intestinal secretions
Does not follow a set pattern:
does not push materials in any 1 direction

10. The oral cavity and pharynx Say “ahhh”

11. Salivary Glands

12. Road map of the tongue

13. Anatomy of Teeth

14. Primary and Secondary Dentitions
Figure 24–9

15. Histology of the Esophagus

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

17. The Swallowing Process
Figure 24–11

18. The Stomach
Figure 24–12a

19. The Stomach
Figure 24–12b

20. The Stomach Lining
Figure 24–13

21. It’s the pits! (Gastric pits that is…)

22. Micrograph of the Fundic region of the gastric mucosa

23. The duodenum, gall bladder and pancreas

24. Hormonal Regulation of Pancreatic secretions

25. The small intestine

26. Histology of the small intestine

27. Cells of the mucosa

28. Duodenal wall

29. Duodenal mucosa

30. Brunner’s (duodenal) glands

31. Crypts of Lieberkuhn!

32. Peyer’s patches in the ileum

33. The Pancreas
Figure 24–18

34. Exocrine tissues of the pancreas

35. Pancreas: Acinar cells

36. The Liver Is the largest visceral organ (1.5 kg)
Lies in right hypochondriac and epigastric regions
Extends to left hypochondriac and umbilical regions
Performs essential metabolic and synthetic functions

37. The Anatomy of the Liver
Figure 24–19

38. Liver Histology
Figure 24–20

39. 3 Functions of the Liver Metabolic regulation Hematological regulation
Bile production

40. Metabolic Regulation The liver regulates:
composition of circulating blood
nutrient metabolism
waste product removal
nutrient storage
drug inactivation

41. Metabolic Activities of the Liver
Carbohydrate metabolism
Lipid metabolism
Amino acid metabolism
Waste product removal
Vitamin storage
Mineral storage
Drug inactivation

42. The Gallbladder and Bile Ducts
Figure 24–21

43. only under stimulation of hormone cholecystokinin (CCK)
The Gallbladder
Stores bile
Releases bile into duodenum:
only under stimulation of hormone cholecystokinin (CCK)

44. Gallstones Are crystals of insoluble minerals and salts
Form if bile is too concentrated
Small stones may be flushed through bile duct and excreted

45. Activities of Major Digestive Tract Hormones
Figure 24–22

46. Hormones of Duodenal Enteroendocrine Cells
Coordinate digestive functions:
secretin
cholecystokinin (CCK)
gastric inhibitory peptide (GIP)
vasoactive intestinal peptide (VIP)
gastrin
enterocrinin

47. 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.

48. Protein digestion in the small intestine

49. Bile salts emulsify fats

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

51. Digestive Secretion and Absorption
Figure 24–27

52. Absorption of Ions and Vitamins
Table 24–4

53. Anatomy of the large intestine

54. The rectum and anus

55. 3 Parts of the Large Intestine
Cecum:
the pouchlike first portion
Colon:
the largest portion
Rectum:
the last 15 cm of digestive tract

56. Characteristics of the Colon
Lack of villi
Abundance of goblet cells
Presence distinctive intestinal glands

57. The End