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Chapter 38 Digestive & Excretory System Question of the day What is the first part of food digestion? Makes contact with your mouth chewing! 38-1 Food & Nutrition Calories Nutrients - substances that provide energy for your body Kinds of Nutrients Water Carbohydrates - Sugar Fats - fatty acids Proteins - amino acids Vitamins - organics Minerals - inorganics Vitamins Vitamins are the ignition of a body Organic molecules work with enzymes to regulate body Important Vitamins: A - retinol (green vegetables) for sight & skin cells B12 - cyanocobalamin (meat, eggs, dairy) for red blood cells C - ascorbic acid (citrus, broccoli) for immune system D - calciferol (fish oil, eggs) for bone growth Minerals Inorganic nutrients body needs in small amounts Body does not digest minerals, loses them Important minerals Calcium - dairy (bones) Potassium - bananas (nerves, acidity) Sodium - salt (body water balance) Iron - meats, grains (hemoglobin & ETC) Zinc - meats, seafood (digestion enzymes) The Need to Balance a Diet Important to have each food group in right proportions 5 necessary groups: Dairy Proteins Veggies Fruits Grains 1 unnecessary group: Fats, Oils, & Sweets Question of the day What is the technical term for chewing your food? Mastication Refers to your muscles in the jaw called masseters 38-2 Process of Digestion Digestion - converts foods into simpler molecules for use Starts in the mouth with teeth chewing Salivary glands kick in - secrete enzymes to digest Enzymes are called Amylase break down sugar Turns food into ball Called BOLUS Next Part of Digestion Once food is swallowed: Moves to PHARYNX (top part of throat) Does NOT go into Larynx That’s your windpipe to lungs Epiglottis prevents food & water going to lungs Moves to ESOPHAGUS By PERISTALSIS - rythmic contractions pushing food to stomach To the Stomach! How does food enter? By a Sphincter (Gateway) Stomach begins digestion 2 ways Chemically Mechanically Digestion (Cont.) Chemical Hydrochloric Acid Mucus - protects stomach lining Pepsin - break proteins Mechanical Stomach muscles contract & churn Mix fluids & foods like washing machine Creates Chyme Moving to Small Intestine Leaves stomach via Pyloric Sphincter Into Small Intestine Gets help from pancreas & liver Removes fats, proteins, carbs thru wall Wall is made of VILLI Small fingers that absorb all nutrients Large Intestine Food is still Chyme Gets to Large Intestine Main goal is to remove remaining nutrients & water Then moves to colon as waste Excreted thru rectum & anal sphincter Called Stool (crap) 38-3 Excretory System Kidney - filters blood Starts in renal artery Goes to Nephron (1000s in a kidney) There water, nutrients go back to body Wastes get filtered, sent to ureter , bladder What is waste called? Urine Cool Nephron Inside Nephron are three important parts: Glomerulus - where artery (blood) comes in Bowman’s Capsule protects glomerulus Loop of Henle - tube that collects water, sends back to body Animals that are efficient w/ water have very long loops of Henle Examples? Camels Other desert animals Sea Birds Kidney Problems & Diseases Two main problems that effect Kidneys: Renal Failure (Dialysis) kidneys shut down and unless something filters blood - you die Diabetes - high blood sugar makes kidneys work very hard Body can’t absorb sugar in blood
