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The Human Digestive System

The Human Digestive System. Major stages of digestion: 1. Ingestion (eating) 2. Digestion (breaking food into molecules the body can absorb) 3. Absorption (nutrients absorbed from digestive tract) 4. Elimination (removal of undigested wastes). Digestive organs HERE.

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The Human Digestive System

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  1. The Human Digestive System

  2. Major stages of digestion: 1. Ingestion (eating) 2. Digestion (breaking food into molecules the body can absorb) 3. Absorption (nutrients absorbed from digestive tract) 4. Elimination (removal of undigested wastes)

  3. Digestive organs HERE http://www.templejc.edu/dept/biology/RHicks/biol2404Int/cavities.gif

  4. http://www.slideshare.net/sciencechris/digestion-366112

  5. INVOLUNTARY

  6. BLUE = ACCESSORY ORGANS The cecum is a pouch connecting ileum with first part of LI. Ileocecal valve (sphincter) markes beginning of LI. Appendix is connected to cecum. http://cikgurozaini.blogspot.com/2010/08/human-digestive-system.html

  7. http://classes.midlandstech.edu/carterp/Courses/bio211/chap23/chap23.htmhttp://classes.midlandstech.edu/carterp/Courses/bio211/chap23/chap23.htm

  8. http://www.beactiviahealth.com/img/estomac.gif

  9. Nucleic acids are another essential ORGANIC nutrient! Water is another essential inorganic nutrient!

  10. Saliva contains mainly water, mucus, buffers and salivary amylase. Salivary amylase: optimal pH is 7.

  11. http://www.slideshare.net/sciencechris/digestion-366112

  12. Glottis – vocal cords and space between them The epiglottis is made of elastic cartilage tissue which guards the entrance of glottis by “closing” as the larynx rises during swallowing so food cannot enter trachea. epiglottis Vocal cords (2 membranes stretched across larynx which vibrate w/ air to produce sound). Closed when holding breath. T R A C H E A glottis http://www.faemse.org/downloads/glottis1.jpg

  13. Peristalsis (wave-like) Alternating contraction & relaxation of smooth muscles propel materials forward all through the alimentary canal.

  14. muscles muscles http://cikgurozaini.blogspot.com/2010/08/human-digestive-system.html

  15. Sphincters close off top & bottom of stomach. Rugae = deep folds in stomach wall (incr. SA). Layers of smooth muscle continue to churn food. http://img.webmd.com/dtmcms/live/webmd/consumer_assets/site_images/articles/image_article_collections/anatomy_pages/stomach_72.jpg

  16. “Gastric Juice” contains mainly water, mucus, HCl and pepsin. Though the stomach is not considered a nutrient-absorption organ, it does in fact absorb small amounts of water, some drugs/medications, glucose & alcohol.

  17. 1. FOOD ENTERS STOMACH 2. GASTRIN PRODUCTION IS STIMULATED 3. HCL PRODUCTION IS STIMULATED 4. PEPSIN IS ACTIVATED BY HCl (optimal pH 2-3)

  18. http://cikgurozaini.blogspot.com/2010/08/human-digestive-system.htmlhttp://cikgurozaini.blogspot.com/2010/08/human-digestive-system.html

  19. “Pancreatic Juice” contains mainly water, NaHCO3, amylase, nucleases, lipases, proteases.

  20. The emulsification process is physical/mechanical, NOT chemical!

  21. http://cikgurozaini.blogspot.com/2010/08/human-digestive-system.htmlhttp://cikgurozaini.blogspot.com/2010/08/human-digestive-system.html http://upload.wikimedia.org/wikipedia/commons/6/64/Illu_pancrease.jpg

  22. We know that the SI is important as the major area of nutrient and water absorption. But let's not forget that it releases enzymes of its own!

  23. http://www.slideshare.net/sciencechris/digestion-366112

  24. http://www.slideshare.net/sciencechris/digestion-366112

  25. http://www.slideshare.net/sciencechris/digestion-366112

  26. Intestinal Lipases also act to break down lipids http://www.slideshare.net/sciencechris/digestion-366112

  27. http://cikgurozaini.blogspot.com/2010/08/human-digestive-system.htmlhttp://cikgurozaini.blogspot.com/2010/08/human-digestive-system.html

  28. PANCREAS -sodium bicarbonate (neutralize chyme – need pH around 8-9 now) -proteases (trypsin, chymotrypsin) -carbohydrases (amylase) -lipases -nucleases LIVER -bile (salts – not an enzyme - to emulsify fats) SMALL INTESTINE -proteaseses (peptidases) -carbohydrases (sucrase, lactase, maltase) -nucleases SI – a busy place!

  29. “Intestinal Juice” contains mainly water, mucus, peptidases, maltase/sucrase/lactase, nucleases and lipases.

  30. http://cikgurozaini.blogspot.com/2010/08/human-digestive-system.htmlhttp://cikgurozaini.blogspot.com/2010/08/human-digestive-system.html

  31. Microvilli are a/k/a “brush border”

  32. Trypsin and chymotrypsinare proteases released by pancreas Carboxypeptidase, aminopeptidase, dipeptidase – all are peptidases (proteases) released by SI itself http://classes.midlandstech.edu/carterp/Courses/bio211/chap23/chap23.htm

  33. http://www.slideshare.net/sciencechris/digestion-366112

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