1. Biology 322 Human Anatomy I Digestive System

2. Functions:

3. Organs Two functional groups: 1. Alimentary Canal or Gastrointestinal tract Organs which ingest, propel, digest, absorb, & eliminate Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anus 2. Accessory Digestive Organs Assist with digestion Teeth, tongue, salivary glands, liver, gall bladder, pancreas

4. Organs:

5. Oral Cavity: Includes: Opens Which

6. Three Pairs of Salivary Glands:

7. From esophagus to anus: Alimentary Canal:

8. Esophagus: Propels food from pharynx to stomach Posterior to trachea & heart : Nonkeratinized stratified squamous epithelium Many mucous-secreting cells Thin lamina propria Thin muscularis mucosa : Thick layer of dense irregular CT : Upper third = skeletal muscle Middle third = mixed Lower third = smooth muscle Thin layer of connective tisssue

9. Esophagus: Passes from thorax to abdomen through diaphragm, enters stomach (left of midline).

10. Stomach: Storage: Highly distensible Delivers

11. Stomach

12. Stomach: Regions

13. Stomach:

16. Small Intestine:Total length: 6 to 7 meters Diameter: 2.5 to 3 centimeters

17. Small Intestine: Three parts

18. Small Intestine: Mucosa Epithelium Lamina propria Muscularis mucosa Submucosa Muscularis Externa Serosa or Adventitia

19. Small Intestine: Mucosa specialized three ways to increase surface area for absorption 1. All layers of mucosa thrown into folds called

20. Small Intestine: Mucosa specialized three ways to increase surface area for absorption 2.Epithelium and lamina propria form finger-like

21. Small Intestine: Mucosa specialized three ways to increase surface area for absorption 3. Plasma membranes of epithelial cells form finger-like

22. Small Intestine: Nutrients, ions, etc. are absorbed through these plasma membranes & passed through the cell to the deeper lamina propria, where they are absorbed into capillaries & lymphatic vessels.

23. Large Intestine (colon): From ileocecal junction to anus ~ 2 meters long ~ 5 to 8 cm diameter

26. Abdominal Accessory Organs: Liver, Gall bladder, Pancreas, & associated ducts

27. Four lobes Blood supply: Liver Most superior organ in abdomen Immediately inferior to diaphragm Partially protected by ribs Develops from embryonic intestine Mass ~ 1.5 kg

28. Liver: Enter / exit together on inferior surface

29. Pancreas: Inferior & posterior to stomach Fits into concavity of duodenum

30. The abdominal cavity is lined

32. More terminology:

34. Intraperitoneal Retroperitoneal