The digestive system

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The digestive system

  1. 1. The Digestive System
  2. 2. Nutrition Nutrition is the study of how food affects the function of living organisms. Food contains nutrients. If cells don’t have nutrients, they don’t function correctly. Poor diet = poor cells. There are six general categories of nutrients.
  3. 3. Six Nutrient CategoriesEnergy Regulatory Suppliers Nutrients Carbohydrates  Water Lipids  Vitamins Proteins  Minerals
  4. 4. 2 Factors leading to NutritionalProblems 1) too little physical activity (sedentary lifestyle) 2) Over consumption of food  Leads to obesity
  5. 5. The Digestive System System is responsible for breaking down food so that it can be absorbed by the bloodstream. The “alimentary canal” is the pathway which food travels through the digestive system.
  6. 6. The Alimentary Canal Mouth Esophagus 26 ft long!!!!!!! Stomach Small intestine Large intestine Rectum* The liver, pancreas, and gallbladder are parts of the digestive system but are not parts of the alimentary canal.
  7. 7. The Mouth Chemical (saliva) and mechanical (chewing) digestion occur in the mouth. Salivary glands produce saliva. Saliva lubricates food. Saliva contains enzyme amylase (starch digestion).
  8. 8. Esophagus 9.8 in Muscular tube. Leads from back of throat (pharynx) to the stomach. Opening to trachea (tube) and esophagus (soft) are right next to each other. Epiglottis prevents food from going down the wrong tube. Muscular contractions (peristalsis) pushes food down the esophagus.
  9. 9. Stomach 4 hours Responsible for protein digestion. Chemical and mechanical digestion. Hydrochloric acid and pepsin (enzyme) break down proteins into amino acids. (pH 1.5-2.5) Stomach lining contains mucus. Mucus protects stomach from acid. Ulcers Sphincter muscles (cardiac and pyloric) control what enters and leaves the stomach.
  10. 10. Small Intestine 20 ft. long. The first part of the small intestine is called the “duodenum.” Remaining carbo’s and proteins are broken down. All lipids are digested in S.I. Gall bladder. (stores bile from the liver & delivers to the S.I.) Duodenum connects to liver and pancreas.
  11. 11. Liver and PancreasSecrete Digestive Enzymes LIVER JOBS PANCREAS JOBS Detoxifies drugs and  Regulates blood alcohol sugar. Secretes bile into  Releases digestive duodenum. enzymes into Bile breaks down duodenum. lipids.  Neutralizes stomach Bile is stored in the acid before it enters gall bladder. S.I.
  12. 12. Small Intestine (cont.) After all nutrients are digested from food, they are absorbed into the blood. S.I. contains lots of capillaries. Mesentary.
  13. 13. Large Intestine All proteins, carbos, and lipids have been removed from food by the time it gets here. Water in food is absorbed into the blood. Vitamins are absorbed into the blood. Whatever food is left is “fecal” matter and passes out the rectum and anus. Feces is undigested food.
  14. 14. Excretory System Kidney  Clean the blood  Vital role in maintaining homeostasis  Removes waste  Regulate amount of water in blood Nephrons- blood cleaning units  Forms urine  Urine contains nitrogenous waste products, excess amounts of water and solutes.  ~1 Liter of urine produced each day.
  15. 15. Reabsorption Returns important substances to the blood. Second process of urine formation
  16. 16. Kidney Disorders & Treatment ~ 13 million people suffer form kidney disorders in the US. Kidney stones-  Uric or oxalic acid, calcium salts, etc. collect outside of kidneys Hemodialysis-  Filtering of blood.  Receive 2x’s a week

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