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DIGESTIVE SYSTEM Mr. Z’s Cool Science Classes

DIGESTIVE SYSTEM Mr. Z’s Cool Science Classes. Digestive System. Digestion - process by which foods are changed into forms the body can use. MOUTH. Our teeth tear and crush food into a fine paste to be swallowed Chewing begins the process of mechanical digestion.

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DIGESTIVE SYSTEM Mr. Z’s Cool Science Classes

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  1. DIGESTIVE SYSTEMMr. Z’s Cool Science Classes

  2. Digestive System • Digestion- process by which foods are changed into forms the body can use

  3. MOUTH • Our teeth tear and crush food into a fine paste to be swallowed • Chewing begins the process of mechanical digestion

  4. What role does our mouth play? • Mechanical Digestion- the physical breakdown of large pieces of food into smaller pieces. • As we chew our food, digestive enzymes breakdown our food this is called chemical digestion.

  5. Just Checking…. • Are the teeth involved in mechanical or chemical digestion? • MECHANICAL!!!

  6. SALIVA • As the teeth cut and grind food, the salivary glands secrete saliva, which moisten food and make it easier to chew. • Saliva begins the process of chemical digestion • Saliva not only eases the passage of food through the digestive system but also begins the process of chemical digestion

  7. SALIVA • Saliva contains an enzyme called amylase that breaks the chemical bonds in starches and releases sugars. • Chemical Digestion- large molecules are broken down into smaller food molecules.

  8. Chew on this for a second… • Take a bite out of your cracker • Chew on the soda cracker for 5 seconds • w/o sharing w/ anyone record how it tastes on paper. • Continue chewing on your cracker for 5 minutes.

  9. Results? • What did your cracker taste like after 5 seconds? • 5 minutes? • How and Why did the taste of the cracker change?

  10. Aha! • Saliva contains an enzyme called_____ . • Amylase • If you chew on a starchy food like a cracker long enough, it will begin to taste sweet. • The sweet taste is a sign that sugar has been released from starch by the action of amylase.

  11. Esophagus • A Chewed clump of food is called a bolus. • As we swallow, the bolus passes through the esophagus into the stomach. • Peristalsis-contractions that squeeze food through the esophagus into the stomach.

  12. STOMACH • Food from the esophagus empties into a large muscular sac called the stomach. • Chyme-mixture of stomach fluids and food produced by contracting stomach muscles.

  13. Small Intestine • As chyme is pushed through the pyloric valve, it enters the duodenum. • Most of the chemical digestion and absorption of the food you eat occurs in the small intestine.

  14. SMALL INTESTINE • Just behind the stomach is the pancreas • The pancreas has 3 main functions • To produce hormones that regulate blood sugar • Produces enzymes that break down carbohydrates, proteins, lipids, & nucleic acids • Produces sodium bicarbonate, base that neutralizes stomach acid.

  15. Accessory Structures of Digestion • Pancreas • Liver-a large organ located above and to the left of stomach. • Produces bile- fluid, acts like a detergent (dissolving and dispersing fats found in fatty foods)

  16. Large Intestine • When chyme leaves the small intestine, it enters the large intestine, or colon. • Primary function: • Remove water from the undigested material that is left.

  17. Digestive System Disorders

  18. To help us organize the information, let’s create a graphic organizer!!

  19. Vocabulary • Digestive system: set of organs involved in the digestion of food.Pharynx: part of the digestive tract between the mouth and the esophagus.Esophagus: part of the digestive tract between the larynx and the cardia of the stomach.Stomach: pocket-like part of the digestive tract, where food is mixed and stored.Pancreas (tail): gland connected to the digestive tract which produces digestive enzymes.Duodenum: beginning of the small intestine.Small intestine: part of the digestive tract between the stomach and the large intestine.Descending colon: part of the large intestine in which food travels downward.Sigmoid: last part of the descending colon.Anus: end of the large intestine, through which the human body expels solid waste.Rectum: last part of the large intestine, between the sigmoid colon and the anus.Appendix: hollow diverticulum fastened to the caecum.Cecum: blind gut formed by the part of the large intestine between the small intestine and the ascending colon.Ascending colon: part of the large intestine where food travels upward.Transverse colon: part of the large intestine where food travels horizontally.Gallbladder: small sac that contains the bile.Liver: digestive gland that produces bile.Tooth: organ set in the jaws and used to cut and crush food.Tongue: organ of taste.

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