GI Basics – Answers

1)  Describe how food gets from your lips to butt.  What organs does it travel through?  Name the organ, and include sphincters, valves, or other important landmarks in the sub-headings.  Don’t peek at the answers until you have tried answering #1 and 2!

1.      Mouth

2.      Esophagus

3.      Stomach

a.       Cardiac Sphincter (Lower Esophageal Sphincter)

b.      Body

c.       Pyloric sphincter

4.      Small Intestines

a.       Duodenum

b.      Jejunum

c.       Ilium

5.      Large Intestines

a.       Ilieocecal valve

b.      Cecum and Appendix

c.       Ascending colon

d.      Transverse colon

e.       Descending Colon

6.      Sigmoid Colon

7.      Rectum

8.      Anal Sphincters


2)  What are the 3 ‘supplementary’ organs in the digestive system?

  1. Liver (the largest organ inside the body, by the way)
  2. Biliary Tract (Gall Bladder)
  3. Pancreas (the only organ that has both endocrine AND exocrine functions)


3)  What are the important functions of each part of the GI system?  Your answers probably won’t be “word for word” the same as mine, so don’t sweat over that, but the gist of it should be the same.

1.      Mouth – Chews your food.  Also, saliva contains amylase, which starts breaking down starches

2.      Esophagus – It gets the food from the mouth to the stomach

3.      Stomach – “Holding tank” for food

a.       Cardiac Sphincter (Lower Esophageal Sphincter)

i.      Stays closed to prevent stomach contents from refluxing back up (that is, unless you’re swallowing, burping, or puking)

b.      Body

i.      Secretes gastric juices, including:

1.      Pepsinogen – breaks down proteins

2.      Hydrochloric Acid (HCl acid)

3.      Lipase – breaks down lipids (fat)

4.      Intrinsic Factor – has to do with vitamin B12 absorption (cobalamin)

c.       Pyloric sphincter – The doorway to the small intestine

4.      Small Intestines

a.       Absorbs nutrients

b.      Secretes:

i.      Secretin – tells pancreas to release bicarb and other enzymes

ii.      Gastrin – tells stomach to make more HCl acid

iii.      Cholecystokinin – causes gall bladder to spit out bile

5.      Large Intestines

a.       Absorb water

b.      Produce bicarb

6.      Sigmoid Colon – Highway for poop

7.      Rectum – Highway for poop

8.      Anal Sphincters – Keeps you from having accidents…hopefully.

9.      Liver

a.       Creates bile to send directly to small intestine AND to store in gall bladder.

10.  Biliary Tract (Gall Bladder)

a.       Gall bladder:  Concentrates and holds bile.  Yum.

b.      Biliary Tract: Is the highway from the gall bladder to the small intestine.

11.  Pancreas – Secretes digestive enzymes into duodenom:

a.       Trypsinogen – Protein digestion

b.      Chymotrypsin – Protein digestion

c.       Amylase – Starch digestion

d.      Lipase – Fat digestion


Fun (but gross) fact:  Solid feces is made of of 30% dead bacteria, 30% fiber, 10-20% fat (from digested epithelial cells and dead bacteria).