2. Small Intestine  Structure that extends from pyloric Sphincter to the beginnings of large intestine

3. Other Functions  Receives secretions from liver and pancreas  Moves Chyme around for better absorption

4. Parts of Small Intestine  Consists of 3 portions: Duodenum, Jejunum, ileum

5. Duodenum  ~ 25 cm long, first portion  It neutralizes stomach acids and breaks down carbohydrates and fats.

6. Jejunum  Main section, ~ 15 feet  Responsible for absorption of most nutrients, except water

7. Ileum  Last section, ~ 6 feet  Responsible for absorbing water and vitamins

8. Intestinal Villi  Found in small intestine  Consists of a layer of simple columnar epithelium  Contains Lacteal, which is a core of blood capillaries and nerve fibers that absorbs nutrients

10. Enzymes  Enzymes embedded in membrane of Villi, used to break down food molecules  Peptidas- splits proteins down to amino acids  Sucrase, maltase, lactace- splits double sugars (disaccharides) into simple sugars (monosacchardies)  Lipase- splits lipids into single carbs

11. Passive Transport  Absorption of certain nutrients into villi without energy. Slow process  Concentration is greater outside the villi

12. Active Transport  Much faster process, requires energy  With help of carrier proteins called ATPase, Amino acid, monosaccharides, and fatty acids get absorbed

13. Carbohydrates and Protein Absorption  Soluble in water  Gets broken down and absorbed directly into blood stream

14. Fat Absorption  Insoluble in water, cannot be absorbed directly  Carrier protein take them to Lacteal where it passes through lymphatic system

15. Nutritional Terms  Macronutrients Carbohydrates, Lipids and Proteins Many bonds, longer to break down, may build up

16. Nutritional Terms  Micronutrients Vitamins, minerals Smaller bonds, easier to absorb

17. Free Radicals  When body takes in oxygen to pair and break down food, 1% of cells will get damaged in the process, creating “Free Radicals”  Very unstable, will steal from other cells to replace molecules.  When stolen, Free Radicals change DNA of cells, creating room for disease  Smoking is a great source of Free Radicals, can lead to cancer

19. Antioxidants  Chemicals that block free radicals from damaging other cells  Donate extra electrons Example: Vitamin E, Flavonoids (Nuts, seeds, fish oil, green tea