1. Pages 469-472 and 483-487

2.  From the stomach to the large intestine:  Duodenum ◦ Attached to the stomach via the pyloric sphincter  Jejunum  Ileum ◦ Meets the large intestine at the ileocecal valve © 2015 Pearson Education, Inc.

3.  Begins in the small intestine via enzymes from: ◦ Intestinal cells ◦ Pancreas  Pancreatic ducts carry enzymes to the duodenum ◦ Bile, formed by the liver, enters the duodenum via the bile duct  The pancreatic and bile ducts come together to form a joint duct that releases into the duodenum – the hepatopancreatic ampulla © 2015 Pearson Education, Inc.

4. Bile duct and sphincter Accessory pancreatic duct Pancreas Jejunum Main pancreatic duct and sphincter Duodenum Hepatopancreatic ampulla and sphincter Duodenal papilla Gallbladder

5.  Three structural modifications increase surface area for food absorption: 1.Villi—fingerlike projections formed by the mucosa  House a capillary bed and lacteal 2.Microvilli—tiny projections off of the villi (create a brush border appearance) 3.Circular folds (plicae circulares)—deep folds of mucosa and submucosa © 2015 Pearson Education, Inc.

6. Blood vessels serving the small intestine Muscle layers Villi Lumen Circular folds (plicae circulares) (a) Small intestine

7. Absorptive cells Blood capillaries Lymphoid tissue Muscularis mucosae (b)Villi Lymphatic vessel Submucosa Villus

8.  Macromolecular breakdown  brush-border enzymes : enzymes released by microvilli of the small intestine  Break down larger sugars into simple sugars  Finish protein digestion  Protective mucus is secreted  Pancreatic juice and bile

9.  Pancreatic Juice: pancreatic enzymes which are specific to the organic molecules they target: ◦ Amylase : starch ◦ A collection of protein enzymes including trypsin ◦ Lipase: fats ◦ Nucleases: nucleic acids ◦ Bicarbonate keeps the pH slightly alkaline  Neutralizes the chyme upon entry to the small int.  Bile: breaks down fats; aids in absorption of fats and fat-soluble vitamins (K, D, E, A)

10.  Neural and hormonal regulation control: ◦ Pace of digestion ◦ Secretion of enzymes and hormones  The presences of chyme stimulates hormone release by the mucosa ◦ These hormones stimulate the release of bile and pancreatic juice

11.  Water and most end products (except fats) are absorbed into the blood via active transport  Fats are absorbed through diffusion ◦ Then they all travel to the liver via the hepatic portal vein  What remains at the ileum: (the end) ◦ Water ◦ Undigestible foods ◦ Lots of bacteria (which cannot enter the blood)  Peyer’s Patches (clusters of lymph tissue) help prevent this

13. Pages 470-472 and 484-486 …Of a senior

14.  Extends from the ileocecal valve to the anus  Subdivisions:  Cecum  Appendix  Colon (has it’s own subdivisions)  Rectum  Anal canal  Functions:  Dry out food residue (absorb any remaining water)  elimination © 2015 Pearson Education, Inc.

15. Transverse colon Haustrum Ascending colon Ileum (cut) Ileocecal valve Cecum Appendix Rectum Anal canal External anal sphincter Sigmoid colon Teniae coli Descending colon Transverse mesocolon

16.  Cecum—first part of the large intestine ◦ Connects to the ileum via the ileocecal valve  Appendix ◦ Cluter of lymphoid tissue  can become inflamed (appendicitis)  Its twisted arrangement allows bacteria to accumulate ◦ Appendage of the cecum © 2015 Pearson Education, Inc.

17.  Colon – ◦ first 3 subdivisions create an upside down “U”  Ascending—travels up right side of abdomen  Transverse—travels across the abdominal cavity  Descending—travels down the left side ◦ Sigmoid—S-shaped region; enters the pelvis  Rectum- connects sigmoid colon to anus ◦ Walls stretch to initiate the defecation reflex © 2015 Pearson Education, Inc.

18.  Anus—opening of the large intestine ◦ Internal anal sphincter—smooth muscle, involuntary control ◦ Remains closed to prevent feces from leaking between defecations ◦ External anal sphincter—skeletal muscle, voluntary control  Sphincters stay closed until neural signals tell them to open Peristalsis initiates defecation Waves of reflexive contractions continue until defecation takes place Defecation can be helped by use of diaphragm and abdominal muscles

19. Transverse colon Haustrum Ascending colon Ileum (cut) Ileocecal valve Cecum Appendix Rectum Anal canal External anal sphincter Sigmoid colon Teniae coli Descending colon Transverse mesocolon

20.  Goblet cells : line the interior surface ◦ produce alkaline mucus ◦ lubricates the passage of feces  Muscularis externa : (the muscular tunic) ◦ three bands of muscle called teniae coli ◦ cause the wall to pucker into haustra (pocketlike sacs) © 2015 Pearson Education, Inc.

21.  Few nutrients remain in food  No digestive enzymes are produced  Bacterial flora within the large intestine metabolize remaining waste:  This creates gas! Yum (methane and hydrogen sulfide)  Synthesize Vitamins K and some B vitamins  Absorption is limited to: ◦ Vitamins produced ◦ Remaining water and ions  Feces- includes undigested food, mucus, bacteria, and any remaining water