Gastrointestinal Anatomy: Large Intestine

Question 1

This is an organ which facilitates the absorption of water and storage of feces until defecation.

Answer 1

Large intestine

Question 2

Where is the large intestine located?

Answer 2

Ascending and descending colon are retroperitoneal

Transverse and sigmoid colon are intraperitoneal

Question 3

This serves as a reserve of large intestine bacteria and can become inflamed.

Answer 3

Appendix

Question 4

What region of the large intestine is the appendix attached to?

Answer 4

The cecum

Question 5

What are the 3 regions of the large intestine?

Answer 5

Cecum, colon and rectum

Question 6

This regulates the passage of material into the large intestine.

Answer 6

Ileocecal valve

Question 7

What are the 3 main modifications of the large intestinal wall? Which layer do these modifications belong to?

Answer 7

Teniae coli (muscularis), haustra, omental appendices

Question 8

These are bands of longitudinal muscle which allows for stronger contractions.

Remember the outer longitudinal layer is discontinous to form these bands of longitudinal muscle.

Answer 8

Teniae coli

Question 9

What are the 2 main cells found in the large intestine mucosa?

Remember: lack of villi in the large intestine means a greater number of glands.

Answer 9

Goblet cells (mucus for protection and lubrication)
Absorptive cells (for water and salt)

Question 10

This is the last part of the large intestine. It stores feces.

Answer 10

Rectum

Question 11

This connects the rectum to the anus.

Answer 11

Anal canal

Question 12

These are responsible for marking the boundary where the epithelium changes.

Additional question: how does the epithelium change coming from the large intestine into the anus?

Answer 12

Anal columns

• epithelium changes from simple columnar epithelium (which is good for absorption and secretion) into stratified squamous to protect against abrasion (in the anus)

Question 13

These 2 structures found within the rectum are responsible for controling defecation.

Additional question: what type of muscle is in both of them?

Answer 13

Internal anal sphincter (smooth muscle - for involuntary movement)

External anal sphincter (skeletal muscle - for voluntary movement)

Question 14

Movement of feces into the rectum stimulates what receptors?

Answer 14

stretch receptors

Question 15

The contractions in the rectum that move feces towards the anus are what kind of contractions?

Answer 15

Peristaltic contractions

Question 16

The defecation reflex is mediated by the _________________ in the _______ _________ and the ___________.

Answer 16

myenteric plexus; sigmoid colon and the rectum.

Question 17

When there is a conscious decision to defecate, the external anal sphincter relaxes/contracts?

Answer 17

It relaxes

• voluntary relaxation of external anal sphincter allows defecation to occur at a convenient time. Similarly with the internal anal sphincter, peristaltic contractions moving the feces down relaxes the internal anal sphincter (just think that as the pressure increases, it will relax the sphincter and therefore open it)

Question 18

True or false. Teniae coli are bands of circular muscle.

Answer 18

False. They are bands of longitudinal muscle.

Question 19

True or false. The regions of the large intestine are the ascending, descending, transverse and sigmoid colon.

Answer 19

False. These are the layers of the colon

The three regions of the large intestine are the: cecum, colon, and rectum

Question 20

This is a wedge shaped organ that detoxifies blood and produces bile. It is also involved in a lot of metabolic processes.

Answer 20

Liver

Question 21

Where is the liver located?

Answer 21

Right side of the body, superior right quadrant of abdominopelvic cavity

Question 22

This is a hollow organ below the liver which is responsible for storing and concentrating bile.

Answer 22

Gallbladder.

Question 23

The gallbladder is connected through which two ducts?

Answer 23

Cystic duct to bile duct

Question 24

How much of the blood supply to the liver comes from the hepatic artery?

Answer 24

1/3 a third

Question 25

How much of the blood supply to the liver comes from the hepatic portal vein?

Answer 25

2/3

Question 26

This is where nutrient rich, deoxygenated blood from small intestine comes from. These then proceed into the liver where they will be processed by what type of cells?

Answer 26

Hepatic portal vein; hepatocytes

• hepatocytes process deoxygenated blood and turn it into bile.

Question 27

What 3 vessels of that supply and connect the liver travel through the lesser omentum?

What is the lesser omentum?

Answer 27

hepatic artery, hepatic portal vein, bile duct

Lesser omentum is what attaches the liver to the stomach.

Question 28

What cells produce bile?

Answer 28

Hepatocytes in the liver

Question 29

What are the functional units that make up the liver?

Answer 29

Lobules

Question 30

These are in between rows of cells in the liver structure.

Answer 30

Liver sinusoids

Question 31

These are located in between cells, and is responsible for receiving bile and carry bile to bile duct.

Answer 31

Canaliculi

Question 32

What is the portal triad?

Answer 32

Branch of hepatic artery, hepatic portal vein and bile duct

Question 33

Where does the central vein drain into?

Answer 33

Hepatic vein

Question 34

Where does the hepatic vein drain into?

Answer 34

inferior vena cava

Question 35

Bile duct joins the pancreatic duct at the?

Answer 35

hepatopancreatic ampulla

• ampulla is a small reservoir where bile duct and pancreatic duct meet. This is where the bile from the liver travels to to get to the gallbladder to be stored and concentrated.