Digestive system

1. Digestive system By Alina Flores, Elizabeth Diaz & Evelyn Cervantes

2. The Digestive System • Mechanical & Chemical breakdown of food • Converts food into energy & nutrients to feed body • Consists of the alimentary canal & the accessory organs

3. Alimentary Canal • Muscular tube about 8 meters long • Passes through thoracic & abdominopelvic cavities

4. Alimentary Canal • Small Intestine • Large Intestine • Rectum • Anus • Consists of : • Mouth • Pharynx • Esophagus • Stomach

5. Alimentary Canal Wall Structure • 4 Layers • Mucosa • Protects tissue beneath • Submucosa • Nourishes surrounding tissues • Muscular Layer • Provides movement of the tube • Serosa • Outer covering of tube

6. Accessory organs • Includes • Salivary glands • Liver • Gallbladder • Pancreas

7. Mouth • Begins digestion • Mechanical digestion • Receives food

8. Cheeks & lips • Cheeks • associates with chewing and expression • Lateral walls of the mouth • Lips • Skeletal muscle • Sensory receptors

9. Tongue • Skeletal muscle • Mixes food • Taste buds to detect sensation • Papillae provides friction • Lingual tonsils • Lingual frenulum

10. Palate • Roof of oral cavity • Hard palate • Soft palate • Uvula • Palatine tonsils • Pharyngeal tonsils

11. Teeth • Breakdown food mechanically • Unique two structures • -primary • -secondary • Types of teeth: • -incisors • -canines • - pre molars • - molars • Enamel as protection

12. Salivary glands • Secrete saliva • Bicarbonate breaks down acid concentration • 3 major glands • - Parotid • - submandibular • - sublingual • Salivary amylase • Mucus

13. Pharynx • Divided into 3 parts • -Nasopharynx • -Oropharynx • -Laryngopharynx • Important passageway • Part of swallowing mechanism • Move food to esophagus

14. Swallowing mechanism

15. Esophagus • About 25 meters long • Propels food from pharynx to stomach • Descends from thorax to trachea • Mucus glands moisten & lubricate • Closes stomach entrance • Prevents regurgitation

17. stomach

18. stomach • Regions • Cardiac region • Fundus (Fundic) region • Body region • Pyloric (Antrum) region • Function: churn/mix food with gastric juices (segmentation), send chyme to small intestine

19. Gastric Enzymes • Function of enzymes: Speed up breakdown of food molecules into their ‘building block’ components • Reactions occur outside of cell lining the gut • Pepsin: degrades food proteins into peptides • Hydrochloric acid: break down foods and release enzymes to continue break down • Intrisic factor: important for absorption of vitamin B12 • Mucin: lubrication and signaling for cell barriers • Gastrin: aids in gastric motility • Rugae: Thick folds in the inner wall of the stomach that disappear when the stomach is destended

21. Regulation of hormones in the digestive system • *Hormones reach target cells by the circulatory system • Stimulating hormones of digestive process • Cholecystokinin (CCK) • Gastrin • Ghrelin • Secretin • Inhibiting hormones of digestive process • Cholecystokinin (CCK) • Gastric inhibitory polypeptide • Enterogastrin • Secretin • Somatostatin

22. Stimulating hormones • Cholecystokinin: • Site of production: Small intestine Mucosa • Target Organ: Pancreas, Gallbladder, Hepatopancreatic Sphincter • Gastrin: • Site of production: Stomach Mucosa • Target Organ: Stomach, Small Intestine, Large Intestine • Ghrelin: • Site of production: Stomach • Target Organ: Brain • Secretin: • Site of production: Small Intestine Mucosa • Target Organs: Pancreas, Liver

23. Inhibiting Hormones • 1. Cholecystokinin: • Site of production: Small Intestine Mucosa • Target Organ: Brain • Gastric Inhibitory Polypeptide: • Site of production: Small Intestine Mucosa • Target Organ: Stomach • Enterogastrin: • Site of production: Small Intestine • Target Organ: Stomach • Secretin: • Site of production: Small Intestine Mucosa • Target Organ: Stomach • Somatostatin: • Site of production: Stomach Mucosa, Small Intestine Mucosa • Target Organ: Stomach, Pancreas, Small Intestine, Gall bladder

25. Pancreas • Function: • Secretes digestive juice, or pancreatic juice • Associated with small intestine • Located posterior to parietal peritoneum

26. Pancreatic Duct • Function: • Transports pancreatic juice to small intestine • Hepatopancreatic Ampulla • Hepatopancreatic Sphincter

27. Pancreatic Juice • After food enters the duodenum the pancreas secretes pancreatic juice • Contains enzymes that break down foods • These enzymes digest carbohydrates, fats, proteins, and nucleic acids

28. Pancreatic Enzymes • Carbohydrate- digesting enzyme: • Pancreatic Amylase: Splits molecules of starch or glycogen disaccharides • Fat-digesting Enzyme: • Pancreatic Lipase: Breaks triglyceride molecules into fatty acids & monoglycerides • Protein-Splitting (Proteolytic) Enzymes: • Trypsin, Chymotrypsin, Carboxypeptidase: Each split bonds between particular combinations of amino acids in proteins, Secreted in inactive forms, Must be activated by other enzymes

29. Regulation of secretion • Nervous and endocrine systems regulate secretion of pancreatic juice • Stimulation of hormones: • Secretin • Cholecystokinin

30. Liver • Functions: • Carbohydrate Metabolism • Produces bile which breaks down fats • Takes glucose and turns it into glycogen • Storage • Blood filtering • Detoxification

31. gallbladder • Function: • Stores bile • Bile exits gallbladder and enters small intestine through the bile duct they share

32. Small intestine • Tubular organ that extends from pyloric sphincter to large intestine • Fills up most of abdominal cavity • 5.5-6 meters long

33. Parts of Small intestine • Duodenum • -shortest & most fixed portion of small intestine • -follows a C shaped path as it passes anterior to R kidney & 3 upper lumbar vertebrae • Jejunum • -Proximal two fifths of small intestine • -diameter of the wall is thicker than ileum • Ileum • -remainder of small intestine • -more lymph nodules • -higher bacterial population

34. Walls of small intestine wall • Inner wall has a velvety appearance • Intestinal villi, most numerous in duodenum and proximal parts of the jejunum • Increase surface area of the intestinal linin, aiding absorption of digestive product • Villi absorbs the fluid that intestinal gland secrete

35. Enzymes of the small intestine • peptidases- which breaks down peptides into amino acids • Sucrose, Maltase & Lactase – breaks down disaccharides into monosaccharides glucose, fructose and glactose • Intestinal lipase – breaks down fat into fatty acids & glycerol • Enterokinase shortens trypsin • Secretion is stimulated by gastric juice, chyre, and reflexes stimulated by expansion od the small intestine

36. Large intestine • Diameter is greater than small intestine • Begins in lower right side of the abdominal cavity the ileum joins cecum • Function: absorbs water & electrolytes • -forms and stores feces • -secretes mucus

37. Parts of large intestine • Consists of cecum, colon, rectum & anal canal • Cecum: - beginning, pouch like • -vermiform appendix is the worm like narrow tube that closes the end (unknown digestion function) • Colon: - Ascending colon – begins at cecum & extends to posterior abdominal wall to piny inferior to the liver • - Transverse colon • – longest and most moveable • - sags un the middle below stomach

38. Continued • - Descending Colon: • - Passes to left abdominal cavity to the brim of the pelivis • -Sigmoid Colon: • - S shaped part, descends from colon to rectum • -walls lack villi & plicaecircularis • - longitudeinal muscle fibers don’t cover the wall • -small collections of fat in serosa on outer surface • - movements are similar to small intestine but slower • - peristaltic waves occur only 2 or 3 times a day • - waves produce mass movements which large secretion of wall constricts inside to move toward rectum

39. rectum • Firmly attached to sacrum by peritoneum • Ends about 5 cm inferior to tip of coccyx • Regulates elimination of feces

40. Anal canal • Formed by last 2.5 – 4 cm of large intestine • Mucus membrane in canal folded in series of 6-8 longitudinal canals • Distal ends of canal opens to the outside as the anus • 2 sphincter muscles guard the anus • Internal anal sphinter muscles, involuntary control, smooth muscle • External anal sphinter muscle, skeletal muscle voluntary control

41. Digestion video

42. Works cited • bioserv. N.p., n.d. Web. 11 Feb. 2015. <http://bioserv.fiu.edu/~walterm/FallSpring/digest_nutrition/digestlect.htm>. • Blue Study. N.p., n.d. Web. 11 Feb. 2015. <https://www.studyblue.com/notes/note/n/an2-16-perineum/deck/11438928>. • "Digestive System: Physiology." kctc.edu. N.p., n.d. Web. 11 Feb. 2015. <http://legacy.owensboro.kctcs.edu/gcaplan/anat2/notes/APIINotes8%20Digestive%20Physiology.htm>. • Dreams time. N.p., n.d. Web. 11 Feb. 2015. <http://www.dreamstime.com/royalty-free-stock-image-large-intestine-3d-image22102016>. • "Human Digestive System." Youtube. N.p., n.d. Web. 11 Feb. 2015. <https://www.youtube.com/watch?v=b20VRR9C37Q>. • Johns Hopkins. N.p., n.d. Web. 11 Feb. 2015. <http://www.hopkinscf.org/what-is-cf/basic-science/gastrointestinal-tract-problems/what-enzymes-do/>. • Boundless. “Hormones of the Digestive System.” Boundless Anatomy and Physiology. Boundless, 06 Feb. 2015. Retrieved 12 Feb. 2015 from <https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/the-digestive-system-23/phases-of-digestion-226/hormones-of-the-digestive-system-1110-6772/> • Sutter Health. N.p., n.d. Web. 11 Feb. 2015. <http://www.cpmc.org/advanced/lapsurg/surgery/procedures/gallbladder.html>. • Wiki Books. N.p., n.d. Web. 11 Feb. 2015.