1. Nutrition & Digestion Ch.18

2. Nutrition Nutrition – process by which we obtain food Nutrition – process by which we obtain food Nutrients – substances used in metabolism. Nutrients – substances used in metabolism. Nutrients obtained thru major food groups. Nutrients obtained thru major food groups. –Bread/Cereal –Fruit/Vegetable –Meat/Fish/Poultry –Dairy –Oils/Fats

3. Types of Nutrition Autotrophs – can make their own food Autotrophs – can make their own food Heterotrophs – can’t make their own food Heterotrophs – can’t make their own food

4. Types of Digestion Mechanical Mechanical –Break food into smaller pieces. –Increases surface area for digestion. Chemical Chemical –Breaks down food molecules into their basic building blocks. Ex) Carbs to monosaccharides Intracellular – within the cell Intracellular – within the cell Extracellular – outside the cell Extracellular – outside the cell

5. Adaptations for Nutrition Protozoan – intracellular diges, osmosis Protozoan – intracellular diges, osmosis Hydra – osmosis, tentacles, stinging cells, Hydra – osmosis, tentacles, stinging cells, gastro-vascular cavity. gastro-vascular cavity. Earthworm – alimentary canal, typhlosole Earthworm – alimentary canal, typhlosole Grasshopper – gizzard/teeth, diges glands Grasshopper – gizzard/teeth, diges glands

6. Basic Nutrients Carbohydrates – monosacchrides Carbohydrates – monosacchrides Proteins – amino acids Proteins – amino acids Lipids – glycerol + fatty acids Lipids – glycerol + fatty acids Vitamins – organic cmpds needed in small amts Vitamins – organic cmpds needed in small amts Minerals – inorganic ions needed in small amts Minerals – inorganic ions needed in small amts Water – most basic & important nutrient Water – most basic & important nutrient

7. Balanced Diet 2000 – 4000 Calories/day 2000 – 4000 Calories/day Diet should supply more than just the energy needed for that day. Diet should supply more than just the energy needed for that day.

9. Human Digestive System 9 meters long w/ specialized sections 9 meters long w/ specialized sections Duct glands – secrete to specific location Duct glands – secrete to specific location Ductless glands – individual cell secretions Ductless glands – individual cell secretions Mucus protects most surfaces Mucus protects most surfaces

11. Mouth Teeth – mechanical digestion Teeth – mechanical digestion Tongue – tastes food, assists swallowing Tongue – tastes food, assists swallowing Saliva – lubricates food for swallowing, Saliva – lubricates food for swallowing, –Mostly Water (90%) –Amylase digests Carbs to Disaccahrides

12. Esophagus Connects mouth to stomach. Connects mouth to stomach. Epiglottis – covers trachea so food enters the esophagus when you swallow. Epiglottis – covers trachea so food enters the esophagus when you swallow. Composed of circular muscles. Composed of circular muscles. Peristalsis pushes food along with a wave of muscle contractions. Peristalsis pushes food along with a wave of muscle contractions.

13. Stomach Stores food 3-4 hours Stores food 3-4 hours Churns food – mechanical digestion Churns food – mechanical digestion Gastric juice – chemical digestion Gastric juice – chemical digestion –Pepsin digests proteins to large peptides –Hydrochloric acid activates enzyme activates enzyme kills bacteria kills bacteria curdles milk curdles milk –Ulcers are holes in stomach lining

14. Liver Accessory Digestive Organ Accessory Digestive Organ Produces Bile – emulsifies fats Produces Bile – emulsifies fats Gall Bladder stores bile & excretes cholesterol Gall Bladder stores bile & excretes cholesterol

15. Pancreas Juices digest all 3 food groups Juices digest all 3 food groups –Amylase: Carbs to disacchrides –Lipase: Fats to glycerol & fatty acids –Trypsin: Proteins to small peptide chains Sodium Bicarbonate – neutralizes acids Sodium Bicarbonate – neutralizes acids Insulin – regulates sugar absortion Insulin – regulates sugar absortion

16. Small Intestine Digestion is completed here Digestion is completed here –Maltase, Sucrase, Lactase digest disaccharides –Lipase digests remaining lipids –Eripsin completes protein digestion to AA’s Absorption of all nutrients occurs here Absorption of all nutrients occurs here –Villi increase surface area of intestine –Microvilli are extensions of villi cells –Blood vessels absorb water soluble nutrients –Lacteals absorb fat soluble nutrients

18. Large Intestine Undigestible materials pass thru here Undigestible materials pass thru here Water is reabsorbed Water is reabsorbed Feces is concentrated remains Feces is concentrated remains Bacteria feed on remains and produce… Bacteria feed on remains and produce… –Vitamin K –Vitamin B 12 Appendix is a vestigial organ (no function) Appendix is a vestigial organ (no function)

19. Rectum Feces is stored here for elimination Feces is stored here for elimination