Digestion.ppt2012
- 1. The Digestive System Presented By: Mrs. Nelson
- 2. Nutrition Nutrition is the study of how food affects the function of living organisms. Food contains nutrients. Nutrients provide the energy and materials organisms need. If organism’s cells are not provided with nutrients, the cells will not function properly. Poor diet = poor cells
- 3. Six Categories of Nutrients Energy Suppliers Carbohydrates Lipids Proteins Non-Energy Suppliers Water Vitamins Minerals
- 4. Carbohydrates Glucose is main source of carbohydrates for animals. Glucose is easily converted to ATP. Glucose is found in fruits, vegetables, grains, and dairy foods. Many foods contain cellulose also known as “fiber.” Important for helping push food through the digestive tract. Energy from food is measured in “calories.”
- 5. Lipids Provide twice as much energy as carbohydrates. Important for… 1) Making cell membranes 2) Hormone production 3) Myelin production 4) Protect organs and insulate body Take long time to digest. Too much fat in diet= excess energy = fat deposits. Saturated fats (solid, contain single bonds) contain LDL cholesterol and build up on arteries.
- 6. Proteins Proteins made of amino acids. 20 different amino acids. Body can make 12/20 amino acids. The other eight must come from food are called “essential amino acids.” Proteins are materials needed for… 1) growth and repair. 2) skin and muscles. 3) regulatory (enzymes- insulin) and transport functions (hemoglobin– RBC).
- 7. Water Most important nutrient. Lubricates areas of body (blood, lymph, plasma, etc.) Coolant for body. Solvent for digestion. Provides fluid environment for cells. Body needs intake 1L of water a day.
- 8. Minerals Inorganic (not made by living things). Plants absorb minerals. Animals eat plants to get minerals. Minerals are only needed in trace amounts by the body. Iron (hemoglobin RBC) Calcium (bones and teeth) Sodium/Potassium (nerve and muscle function) Magnesium/Zinc/Iodine
- 9. Vitamins Organic (made by living things). Help regulate body processes. Most obtained from food. Vitamin K- made by bacteria in digestive tract. Vitamin D- synthesized by skin cells when exposed to sunlight. 2 types vitamins… 1) Fat soluble- can be stored in fatty tissues for future use (A, D, E, K) 2) Water soluble- dissolve in water and can not be stored by body (C, B)
- 10. Importance of Various Vitamins A, C, D, E, K, Folic Acid, B12 Helps RBC mature
- 11. The Digestive System System is responsible for breaking down food so that nutrients can be absorbed by the bloodstream. The “alimentary canal” is the pathway which food travels while it is digested.
- 12. The Alimentary Canal Mouth Esophagus 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.
- 14. The Mouth Chemical digestion –saliva contains enzyme amylase that digests carbohydrates (starches) Mechanical digestion- chewing
- 15. Esophagus Tube from back throat to stomach. Trachea (lungs) and esophagus are next to each other. Epiglottis prevents food from going down the wrong tube. Peristalsis- muscular contractions pushes food down esophagus.
- 16. Stomach Chemical/mechanical digestion. Hydrochloric acid and pepsin (enzyme) break down proteins to amino acids. Stomach lining contains mucus. Mucus protects stomach from acid (ulcers). Sphincter muscles (cardiac and pyloric) control what enters and leaves the stomach (heartburn).
- 17. Small Intestine 20 ft. Remaining carbohydrates and proteins are broken down. All lipids are digested here. Connected to liver and pancreas.
- 18. Liver and Pancreas LIVER JOBS Makes and secretes bile (needed digest lipids). Bile is stored in the gall bladder. Detoxifies drugs and alcohol. PANCREAS JOBS Regulates blood sugar. Secretes digestive enzymes into small intestine. Neutralizes stomach acid as it enters the small intestine (bicarbonate).
- 19. Small Intestine (cont.) After all nutrients are digested, they are absorbed. This is the major job of this organ. S.I. contains lots of capillaries. Mesentary.
- 20. Large Intestine All proteins, carbohydrates, and lipids have been removed from food by the time it gets here. Water is absorbed (diarrhea). Vitamins are absorbed. Feces is undigested food passes out rectum and anus.