Presentation Transcript

1. Nutrition A bit about nutrition in general plus the specifics of the human digestive system.

2. What is Nutrition? • Definition:The process by which organisms get food and break it down to use for their metabolism • The nutrients humans need every day are: water, fats, proteins, vitamins, and minerals.

3. The Human Diet • The average human should ingest about 2,000 Calories/day. This is less than you may think… • Age, gender, lifestyle, weight, and body condition all affect daily Caloric needs.

6. Organs: The Mouth • Breakdown of food begins in the mouth. • Starches are broken down by an enzyme called salivary amylase.

7. Organs: The Esophagus • The tube that connects the mouth to the stomach and also begins the process of peristalsis. • Peristalsis: The movement of food down the digestive tract by waves of muscle contractions

8. Peristalsis This is the esophagus

9. Organs: The Stomach • A thick-walled muscular sac that contains enzymes and gastric juices (HCl). • The enzyme Pepsin breaks down proteins in the stomach

10. The Stomach Interesting Fact: It takes approximately 12 hours to completely digest food.

11. Organs: Small Intestine • Coiled tube about 20 ft. long and 2.5 cm. in diameter. • Most digestion and ALL nutrient absorption is completed here. • Lined with millions of tiny “fingers” called villi which increase surface area and aid in absorption of nutrients.

12. These are villi

13. Small Intestinal Enzymes • Amylase, Maltase, Sucrase, Lactase • Continued breakdown of starches • Trypsin, Peptidase • Continued breakdown of proteins • Lipase • Breakdown of fats

14. Organs: Large Intestine • Tube about 5 ft. long and 6 cm. in diameter…No digestion occurs here! • Functions: • Reabsorption of water • Reabsorption of vitamins (K and B) created by E. coli bacteria! • Elimination of feces through the anus (stored in rectum)

16. Inside the Large Intestine

17. Other Important Organs • Liver: Produces bile which breaks down fat in the small intestine • Gall Bladder: Stores bile • Pancreas: Releases enzymes into the small intestine.

18. Pancreas Liver Gallbladder Small Intestine

19. Digestive Waste… Feces- the science word for “poop” Defecation- the act of “pooping” Elimination- to get rid of waste from the digestive system (it has never been in your cells, only in your digestive tract). Excretion- to get rid of cellular waste (urine, sweat, exhaled CO2).

20. The End