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Chapter 38. Digestive & Excretory System. What is the first part of food digestion? Makes contact with your mouth - chewing!. Question of the day. 38-1 Food & Nutrition. Calories Nutrients - substances that provide energy for your body Kinds of Nutrients Water Carbohydrates - Sugar
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Chapter 38 Digestive & Excretory System
What is the first part of food digestion? Makes contact with your mouth - chewing! Question of the day
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
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) Minerals
Important to have each food group in right proportions 5 necessary groups: Dairy Proteins Veggies Fruits Grains 1 unnecessary group: Fats, Oils, & Sweets The Need to Balance a Diet
What is the technical term for chewing your food? Mastication Refers to your muscles in the jaw called masseters Question of the day
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 38-2 Process 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 Next Part of Digestion
How does food enter? By a Sphincter (Gateway) Stomach begins digestion 2 ways Chemically Mechanically To the Stomach!
Chemical - Hydrochloric Acid Mucus - protects stomach lining Pepsin - break proteins Mechanical - Stomach muscles contract & churn Mix fluids & foods like washing machine Creates Chyme Digestion (Cont.)
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 Moving to Small 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) Large Intestine
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 38-3 Excretory System
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 Cool Nephron
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 Kidney Problems & Diseases