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The Digestive and Endocrine Systems. Ch. 35. Feed Me!. Digestive system uses mechanical and chemical energy to break organic material Material is absorbed into the cells of our bodies; used to make energy or other molecules Mechanical: Grinding, smashing tearing, crushing Chemical:
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Feed Me! • Digestive system uses mechanical and chemical energy to break organic material • Material is absorbed into the cells of our bodies; used to make energy or other molecules • Mechanical: • Grinding, smashing tearing, crushing • Chemical: • Enzymes and Acidic solutions
The Mouth: Mechanical • Chewing: • Tearing and grinding food into small lumps; increase surface area for enzyme activity • Teeth: • Strongest bones in the body • Incisors; cutting food • Cuspids; tearing food • Molars; grinding food • Tongue: • Strongest muscle in the body • Pushes food down esophagus
The Mouth: Chemical • Amylase: • Enzyme that breaks down starch into di and monosaccharaides • Taste buds: • Alert us to nutrients we need to consume • Sugar Sweet • Acids Sour • Toxins Bitter • Salts Salty • Protein Umami • Tonsils: • Protect body from bacteria take in through the mouth and nose
The Esophagus • Swallowing pushes food down the esophagus to the stomach • Peristalsis: • Contractions of muscle waves move food in one direction • Food has to pass by the trachea (entrance to the lungs) so a small cartilage cover (epiglottis) blocks the opening • Eating too fast can send food “Down the Wrong Pipe”
The Stomach: Mechanical • Walls of stomach contract to crush food and help mix food with digestive juices
The Stomach: Chemical • Glands in stomach release Pepsin and HCl • Pepsin breaks down proteins into amino acids • HCl keeps the stomach at a pH 2! • Food can take up to 4 hours to digest • Why doesn’t HCl eat through the stomach? • Lining of stomach makes protective mucus
Heart Burn and Stomach Ulcers • “Heart Burn” is when stomach acid gets into the esophagus and causes a burning feeling in the chest • Caused by spicy food • Stomach Ulcer is a hole in the stomach lining which can cause major health problems • Caused by high acidic levels
The Small Intestine: Mechanical • 6 m long but only 2.5 cm wide • Peristaltic contractions move food through intestine and continue to break down food • Food is absorbed into the blood through villus
The Small Intestine: Chemical • 3 pronged attack in the Duodenum (first 25cm) • Pancreas releases enzymes to break down carbohydrates, proteins, and fats • Liver releases “Bile” which breaks down fats • Gallbladder releases extra bile to break large fat groups into small drops
The Large Intestine • Only 1.5m long but 6.5cm wide • Indigestible material is compacted as much water as possible is absorbed back into the body • Anaerobic bacteria produce vitamins B and K for us while digesting the material • After 18-24 hours, waste is removed from the body as feces • Passes through the last part of the digestive system, the rectum (the butt)
Homework • Ch. 35 workbook • Group Presentation: • Each group will present on a vital nutrient • Use a ppt, images, videos, live demonstrations, etc… • Each group must explain: • Why is their nutrient important to the body • How does it keep us healthy • How much should we consume each day • Where can we get this nutrient from Each group must supply me with 3 quiz questions on their nutrient. I may use these to create your next quiz. All group members must speak! Give me your PPT by next Friday so I can check they work on my PC!!