The Alimentary Canal

1. The Alimentary Canal - the one way passageway for food / nutrients / waste

2. The Alimentary Canal

3. Human Alimentary Canal • Mouth • Pharynx • Esophagus • Stomach • Small intestine • Large intestine

4. Mouth • True digestive organ • physical & chemical digestion • Salivary Amylase breaks carbohydrates into disaccharides/maltose • contains teeth, tongue, soft & hard palate to help with physical digestion • food is ingested

5. Salivary Glands • Accessory Organs • produce salivary amylase • sublingual • submandibular • parotids

6. Pharynxaka. The throat • True digestive organ • no physical or chemical digestion occurs here • hooks in with the respiratory system

7. Esophagus • True digestive organ • no physical or chemical digestion occurs here • food considered a bolus - wet ball of chewed food • PERISTALSIS starts here - wavelike contractions of the tube that moves the foodstuff along the alimentary canal

8. The Alimentary Canal

9. Stomach • Very muscular organ that participates in both physical & chemical digestion • true digestive organ • lined with thick protective mucous • the enzyme pepsinogen activates in the acid conditions in the stomach and becomes pepsin • pepsin digests the proteins into groups of 2 amino acids • cardiac sphincter valve is at the top and the pyloric valve is between the stomach & small intestine • the bolus is now considered chyme

10. The Alimentary Canal

11. Small Intestine • True digestive organ • chemical digestion is completed here • contains 3 main portions • duodenum first 10 cm of small intestine • jejunum next 2 ½ meters • ileum last 4 meters • the role of the small intestine is threefold • 1. Finish digestion • 2. Absorb nutrients • 3. Storage • contains villi for absorption of nutrients

12. Small IntestineEnzyme Action • Common bile duct hooks into duodenum • this hooks up to the pancreas and gallbladder • pancreatic juice & bile is secreted is secreted through this • BILE & bile salts- emulsifies the fat - breaks into smaller droplets • Pancreatic Juice contains: • sodium bicarbonate / to neutralize the acid from the stomach • lipase / breaks fats into fatty acids & glycerol • trypsinogen in changed into trypsin in the si. Environment and digests the dipeptides into single amino acids • pancreatic amylase finishes carbohydrate digestion by breaking disaccharides into monosacharides

13. Villi • Increases the surface area in the small intestine for the maximum nutrient absorption • monosaccharides & amino acids are diffused into the capillaries  bloodstream • fatty acids & glycerol are absorbed by the lacteal which hooks into the lymphatic system

14. Pancreas • Accessory digestive organ • produces pancreatic juice which contains pancreatic amylase, sodium bicarbonate, trypsinogen and lipase • located under the stomach

15. LIVER produces bile which breaks up the larger fats GALLBLADDER stores the bile until needed

16. The Alimentary Canal

17. Large Intestine • True digestive organ, but digestion is all done by now!!! • The function is to absorb water & minerals • at the junction of the small & large intestine is the appendix • there are 5 portions of the large intestine • ascending colon • transverse colon • descending colon • sigmoid colon • rectum which ends in the anal sphnicter • methane in is a normal bi-product and in combination with e. coli bacteria produce flatulence

18. At this point the waste products are referred to as feces • CONSTIPATION - waste sits in large intestine too long and the stool becomes too hard and is difficult to evacuate • DIARRHEA - waste does not sit in the large intestine long enough and not enough water is absorbed  producing a watery stool

19. The Alimentary Canal

20. GASTRIN - cells of the stomach secrete into bloodstream triggers cells of stomach to secrete hydrochloric acid so pepsinogen converts to pepsin SECRETIN - when food enters the small intestine secreted by the cells of si. Into the bloodstream triggers pancreas to make pancreatic juice Hormones of the Digestive System