Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Nutrition & Digestion - Regional School District 17
Document related concepts
no text concepts found
Transcript
Nutrition & Digestion Ch.18 Nutrition • Nutrition – process by which we obtain food • Nutrients – substances used in metabolism. • Nutrients obtained thru major food groups. – – – – – Bread/Cereal Fruit/Vegetable Meat/Fish/Poultry Dairy Oils/Fats Types of Nutrition • Autotrophs – can make their own food • Heterotrophs – can’t make their own food Types of Digestion • Mechanical – Break food into smaller pieces. – Increases surface area for digestion. • Chemical – Breaks down food molecules into their basic building blocks. Ex) Carbs to monosaccharides • Intracellular – within the cell • Extracellular – outside the cell Adaptations for Nutrition • Protozoan – intracellular diges, osmosis • Hydra – osmosis, tentacles, stinging cells, gastro-vascular cavity. • Earthworm – alimentary canal, typhlosole • Grasshopper – gizzard/teeth, diges glands Basic Nutrients • Carbohydrates – monosacchrides • Proteins – amino acids • Lipids – glycerol + fatty acids • Vitamins – organic cmpds needed in small amts • Minerals – inorganic ions needed in small amts • Water – most basic & important nutrient Balanced Diet • 2000 – 4000 Calories/day • Diet should supply more than just the energy needed for that day. Human Digestive System • 9 meters long w/ specialized sections • Duct glands – secrete to specific location • Ductless glands – individual cell secretions • Mucus protects most surfaces Mouth • Teeth – mechanical digestion • Tongue – tastes food, assists swallowing • Saliva – lubricates food for swallowing, – Mostly Water (90%) – Amylase digests Carbs to Disaccahrides Esophagus • Connects mouth to stomach. • Epiglottis – covers trachea so food enters the esophagus when you swallow. • Composed of circular muscles. • Peristalsis pushes food along with a wave of muscle contractions. Stomach • Stores food 3-4 hours • Churns food – mechanical digestion • Gastric juice – chemical digestion – Pepsin digests proteins to large peptides – Hydrochloric acid • activates enzyme • kills bacteria • curdles milk – Ulcers are holes in stomach lining Liver • Accessory Digestive Organ • Produces Bile – emulsifies fats • Gall Bladder stores bile & excretes cholesterol Pancreas • 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 • Insulin – regulates sugar absortion Small Intestine • 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 – – – – Villi increase surface area of intestine Microvilli are extensions of villi cells Blood vessels absorb water soluble nutrients Lacteals absorb fat soluble nutrients Large Intestine • Undigestible materials pass thru here • Water is reabsorbed • Feces is concentrated remains • Bacteria feed on remains and produce… – Vitamin K – Vitamin B12 • Appendix is a vestigial organ (no function) Rectum • Feces is stored here for elimination
