Digestive system: hindgut

Question 1

When does the aorta bifuricate

Answer 1

L4

Question 2

Name the 3 main branches of the inferior mesenteric artery

Answer 2

the left colic artery (most superior), sigmoidal arteries (multiple), and the superior rectal artery (most inferior)

Question 3

What does the left colic artery split into

Answer 3

ascending and descending branch

Question 4

What does the ascending branch of the left colic artery do

Answer 4

ascends to anastomose with the left branch of the middle colic artery, meaning the ascending branch vascularizes part of the descending colon

Question 5

What does the ascending branch of the left colic artery do after it has vascularized part of the descending colon

Answer 5

Then goes intraperitoneal into the transverse mesocolon and vascularizes the distal third of the transverse colon

Question 6

Where does the descending branch of the left colic artery go

Answer 6

ascends along the descending colon and sends off branches to supply the descending colon, it anastomoses with the next branch down.

Question 7

Where do the sigmoidal arteries enter

Answer 7

the sigmoid mesocolon

Question 8

What do the sigmoidal arteries form

Answer 8

form arcades and vascularize the distal part of the descending colon and the sigmoid colon

Question 9

What does the superior rectal artery supply

Answer 9

distal part of the sigmoid colon and the proximal rectum

Question 10

Where does the superior rectal artery run

Answer 10

crosses over the common iliac vessels, and enters the pelvic cavity

Question 11

Where does the superior rectal artery split

Answer 11

splits into 2 branches (at the level of S3) and descends down the sides of the rectum.

Question 12

What happens in the large intestine

Answer 12

water and electrolytes are absorbed from the intestinal contents, causing the contents to change from liquid to solid

Question 13

What does the large intestine consist of

Answer 13

the caecum, appendix, colon, rectum and the anal canal

Question 14

Where does the cecum hang

Answer 14

hangs downward in the right iliac fossa, lying almost free of peritoneal attachments.

Question 15

What are the 4 parts of the colon

Answer 15

ascending, transverse, descending and sigmoid colon

Question 16

How is the longitudinal muscle in the large intestine different to the small intestine

Answer 16

The longitudinal muscle isn’t continuous, it is gathered into 3 stripes called tenia(e) coli.

Question 17

What are sacculations in the large intestine

Answer 17

The longitudinal muscle is shorter than the length of the colon and have a drawstring effect producing bulging sacculations

Question 18

What are diverticuli in the large intestine

Answer 18

they are protusions of mucosa through the muscular layer

Question 19

What is the mucus membrane of the large intestine like

Answer 19

smooth because they have no villi

Question 20

What covers the ascending colon

Answer 20

peritoneum from the posterior abdominal wall, covers the front and sides

Question 21

Where does the ascending colon end

Answer 21

at the right colic flexure (hepatic flexure)

Question 22

Where does the hepatic flexure lie

Answer 22

just below the lowest part of the liver and gall bladder and in front of the lower part of the right kidney.

Question 23

How does the transverse colon cross the abdominal cavity

Answer 23

from right to left

Question 24

Where does the transverse mesocolon cross

Answer 24

crosses the head of the pancreas, and the duodenum

Question 25

What connects the transverse colon to the greater stomach

Answer 25

the gastrocolic ligament

Question 26

How does the transverse colon end

Answer 26

as the left colic (splenic) flexure

Question 27

Where does the splenic flexure lie

Answer 27

just below the spleen and in front of the left kidney

Question 28

Where does the descending colon become the sigmoid colon

Answer 28

a little below the iliac crest

Question 29

What does the sigmoid colon form

Answer 29

a large freely mobile loop that is attached by the sigmoid mesocolon

Question 30

Where does the sigmoid colon run

Answer 30

passes down into the pelvic cavity, and approaches the midline

Question 31

How does the sigmoid mesocolon end

Answer 31

becomes shorter as it enters the pelvis and then ends all together at S3 where it merges with the rectum

Question 32

Where is the visceral peritoneum on the liver

Answer 32

posteroinferior

Question 33

Where is the round ligament found

Answer 33

in the falciform ligament

Question 34

What is the round ligament a remnant of

Answer 34

The fetal umbilical cord

Question 35

What is ligamentum venosum a remnant of

Answer 35

the ductus venosus of the foetus drainage system

Question 36

Where is the ligamentum venosum attached to

Answer 36

the left branch of the portal vein within the portal hepatis

Question 37

Where does the coronary ligament attach

Answer 37

attaches the superior surface of the liver to the inferior surface of the diaphragm and sets the boundaries of the bare surface of the liver

Question 38

What are the 4 parts of the duodenum

Answer 38

1st part (superior part), 2nd part (descending part), 3rd part (inferior and horizontal part), 4th part (ascending part)

Question 39

What is the anterior relation to the spleen

Answer 39

stomach

Question 40

Posterior relation to the spleen

Answer 40

diaphragm (separated it from pleura, lungs and ribs 9-11)

Question 41

Inferior relation from the spleen

Answer 41

left colic flexure

Question 42

Medial relation of the spleen

Answer 42

left kidney

Question 43

Venous drainage of the bowel

Answer 43

There are no veins from the bowel

Question 44

How much blood does the portal vein bring to the liver

Answer 44

75-80%

Question 45

How is the portal vein formed

Answer 45

by the splenic vein and superior mesenteric vein uniting

Question 46

Where is the portal vein formed

Answer 46

posterior to the neck of the pancreas

Question 47

Where does the inferior mesenteric vein drain

Answer 47

splenic vein but may drain into the junction between the superior mesenteric and splenic veins.

Question 48

When portal circulation is obstructed how can blood still reach the heart

Answer 48

through IVC by way of anastomoses (no valve - blood can flow in reverse direction)