Topic 5 Digestive System: Large Intestine (colon)

Question 1

• Where water and salts are reabsorbed to form feces

- 1.5 m long

Answer 1

Large Intestine

Question 2

1. Major functions are water and electrolyte absorption
2. Feces stored at the end of large intestine in the rectum -> excreted through the anus. Malfunction of large intestine often leads to diarrhea
3. Healthy feces breakdown: 75% water and 25% solid mass containing 30% dead cells, 10-20% fat, 10-20% organic matter, 2-3%protein, 30% roughage (cellulose) and undigested matter (sloughed cells)
4. At the beginning of the large intestine is the cecum (before the ascending colon). Has an offshoot of unknown function known as appendix. In herbivores, the large cecum functions in cellulose digestion with help of bacteria
5. Bacteria (like E. coli), a symbiont in large intestine, is the main source of vitamin K (also produce Vitamin B12, thiamin, riboflavin)

Answer 2

Process

Question 3

• Liver’s bile and pancreatic digestive enzymes all come together with food in the duodenum; opening is the sphincter of oddi

Answer 3

Note