1 / 19

Digestive System

Explore the intricacies of the digestive system, including the structures like the esophagus, stomach, liver, and more. Learn about the functions of the mouth, small intestine, and large intestine, and how food is broken down and absorbed. Discover the roles of various enzymes and hormones in digestion, and the importance of microbiota in the gut. This comprehensive guide will take you on a journey through the entire gastrointestinal tract, explaining each step of the digestive process in an informative and engaging manner.

johnmjones
Download Presentation

Digestive System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Digestive System You are what you eat Oh my!!!!

  2. A. Overview of structure • Esophagus • ??? • Stomach • Liver • Pyloric valve • Pancreas • Duodenum • Jejunum • Ileum • Ileocecal valve-appendix • colon

  3. B. Mouth • Different types of teeth • Functions of tongue • Uvula • Salivary glands • Salivary amylase • Food bolus • Mechanical digestion • Deglutition http://www.youtube.com/watch?v=wqMCzuIiPaM

  4. C. Esophagus 1. 10” long • Stratified squamous epithelium • Hiatal hernia • GERD • Peristalsis of bolus • http://www.youtube.com/watch?v=Q-n_Q0qKXzg

  5. D. Stomach • Cardiac region • Fundus • Body • Pyloric region • Pyloric sphincter • Rugae-full can hold 4 liters • Storage tank • Mechanical breakdown • http://www.youtube.com/watch?v=hpS5kMn_B0I&feature=related

  6. 9. Gastric pits • Produce gastric juice • Intrinsic factor-needed for absorption of vit B • Chief cells-pepsinogen • Parietal cells-HCl • Mucous neck cells • Enteroendocrine cells-D and G cells produce hormones • rennin

  7. 10. Stomach physiology • Pepsinogen to pepsin • Pepsin proteolytic • Rennin • No other chemical digestion • Very little absorption • Aspirin and alcohol

  8. 11. Gastric motility • Peristalsis begins upper half • Increases in force • 3 ml or less squirts through • Rest is refluxed back into stomach • http://www.youtube.com/watch?v=hpS5kMn_B0I • http://www.youtube.com/watch?v=o18UycWRsaA&feature=related

  9. E. Small intestine • 7-13 feet • Suspended by mesentery • Duodenum “twelve finger widths”-5% • Jejunum “empty”-40% • Ileum “twisted intestine”-60% • Ileocecal valve • Major digestive structure

  10. 8. Structures adapted to increase surface area • Plicaecircularis • Microvilli • Villi • Lacteal-lymphatic capillary • Modifications decrease in significance toward ileum • Peyer’s patches increase in number

  11. 9. Duodenum • Shortest segment-interesting features • Pancreas opens here • Bile enters from liver • Brunner’s glands in tunica submucosa-alkaline mucous • Crypts of Lieberkuhn-intestinal juice relatively enzyme poor but release lysozyme-antibacterial enzyme

  12. 10. Movements in small intestine • Modified peristalsis • Peristalsis starts in duodenum • Starts strong and dies down • Next peristaltic wave starts further down • Moves food a little further on • Second type of muscular activity • Segmentation http://www.youtube.com/watch?v=GdNtRom-Pvs • Kind of like making meatloaf • Random contractions superimposed upon peristaltic waves

  13. 11. Food breakdown via action of pancreas a. Carbo and protein digestion already begun • No fats digested • 3-6 hours • Endocrine function • Pancreatic juices -huge amount of digestive enzymes -pancreatic amylase -trypsin, chymotrypsin digest proteins -lipases -rich supply of bicarbonate

  14. 12. Liver-huge number of functions • Most important digestive function production of bile • Fat emulsifier • Stored in gall bladder • Large droplets scattered into small • Increases surface area for digestion • Also improves fat and cholesterol absorption • Excretion of bilirubin • 500-1000 ml per day

  15. 13. Gall bladder • About size of kiwi fruit • Stores bile • Concentrates bile • Gall stones

  16. F. Large intestine-a.k.a. colon • 5 feet but larger in diameter • Extends from • Parts • Appendix • Longitudinal muscle not continuous-three bands • haustra

  17. 7. Functions of large intestine • Few nutrients-remains for 12-24 hours • No digestive enzymes • Resident bacteria -many different species -sometimes described as the forgotten organ -evolved in a mutualistic relationship -metabolize remaining nutrients -make vitamin K and B complex -keep out harmful species d. Dry residual material e. Lubricate material for defecation

  18. 8. Propulsion of Residue and defecation • Haustral contractions • Mass movements • Sphincter muscles

  19. 9. Imbalances • Diverticulosis • Diverticulitis • Diarrhea • Constipation

More Related