1. Overview: Digestion and Absorption NFSC 303 McCafferty

2. Digestion & Absorption: Overview Digestion: breakdown of nutrients in the GI tract –Mechanical and chemical Absorption: transfer of nutrients through the wall of the GI tract, into circulation Involved in D&A –GI tract –Auxiliary organs: ________________________________

3. Pancreas: –Exocrine function: –Endocrine function: Liver: (many functions…) –Digestive function: Gallbladder –

5. Digestion Mouth –Mechanical action: biting, chewing –Chemical action: Saliva - Enzymes – Esophagus –Passage tube to stomach only –Muscular contractions propel food down

7. Stomach –Mechanical “churning” and peristalsis –Chemical: water enzymes HCl = – –

8. Semi-liquid _______________ –Released into small intestine in small amounts

9. Small Intestine –Most digestion and absorption occur here –Peristalsis and Segmentation chyme mixed with more enzymes bicarbonate (to reduce acidity), and bile (involved in fat absorption)  “Lower” small intestine: – –

10. Large Intestine (Colon): –Removes excess water and salts (electrolytes), forms feces. Rectum and Anus: –Feces is held in rectum until eliminated through the anus.

12. Absorption Most absorption occurs in the small intestine… so let’s go back to the small intestine for a moment…

13. Small intestine wall – thousands of folds

14. Nutrients pass through the intestinal cells and then into blood or lymph –Capillaries: –Lymph vessels:

16. Now we have all the nutrients on the inside of the body. –In the next section, we’ll learn all about 1)carbohydrates, 2) digestion and absorption of CHO, and 3) utilization of CHO once inside the body.