Hindgut and Associated Arteries, Liver, Gall Bladder and Biliary Tree

Question 1

Which artery supplies the hindgut?

Answer 1

Inferior mesenteric artery

Question 2

At what vertebral level is the IMA given off?

Answer 2

L3

Question 3

What components make up the hindgut?

Answer 3

Distal third of transverse colon, descending colon, sigmoid colon and rectum

Question 4

Which vessels contribute to the formation of the marginal artery? What does it supply?

Answer 4

SMA: middle colic
IMA: left colic, sigmoid

Supplies area around splenic flexure

Question 5

Aortic aneurysms can compress the IMA. Why doesn’t this impair gut function?

Answer 5

Due to collateral circulation supplied by the marginal artery

Question 6

How is the sigmoid attached to the posterior body wall?

Answer 6

Sigmoid mesocolon

Question 7

At what vertebral level does the sigmoid become the rectum?

Answer 7

S3

Question 8

From the rectosigmoid junction, what changes can be seen in the structure of the hindgut?

Answer 8

Absence of taenia coli and appendices epiploicae

Question 9

What is a sigmoid volvulus? Why is it a serious condition?

Answer 9

Obstruction of bowel due to twisting around sigmoid mesocolon

Can lead to chronic constipation, bowel ischaemia

Question 10

The rectum runs from the __1__ to the __2__, about __3__ cm above the cutaneous margin of the anus

Answer 10

1) rectosigmoid junction
2) ano-rectal junction
3) 3

Question 11

How many lateral curves are found in the rectum? What marks each curve on the interior?

Answer 11

Three

Each marked by a transverse fold or valve (2 on the left, middle one on the right)

Question 12

What are the three main vessels (some may be paired) that supply the rectum?

Answer 12

Superior rectal

Middle rectal

Inferior rectal

Question 13

From where does the superior rectal artery originate?

Answer 13

Inferior mesenteric artery

Question 14

From where does the middle rectal artery originate?

Answer 14

Internal iliac

Question 15

From where does the inferior rectal artery originate?

Answer 15

Internal pudendal

Question 16

What is the definition of a portal vein? Are there any others (other than the hepatic portal vein)?

Answer 16

Blood vessel that takes blood from one capillary bed to a second prior to it entering the vena cava and returning to the heart.

Yes, around the pituitary gland

Question 17

Which vessels unite behind the neck of the pancreas?

Answer 17

Superior mesenteric vein and splenic vein unite to form the hepatic portal vein

Question 18

The hepatic portal vein is a continuation of which vessel?

Answer 18

Superior mesenteric vein

Question 19

The portal vein runs in what structure?

Answer 19

Free edge of lesser omentum

Question 20

What is the distribution of the inferior mesenteric vein?

Answer 20

Runs superiorly, well to the left of the IMA. Usually joins the splenic vein behind the body of the pancreas, just before the union of the splenic vein with the superior mesenteric vein.

Question 21

The right gastric vein drains into which vessel?

Answer 21

Portal vein

Question 22

The left gastric, short gastric, and left gastroepiploic veins drain into which vessel?

Answer 22

Splenic vein

Question 23

The right gastroepiploic and superior pancreaticoduodenal veins drain into which vessel?

Answer 23

Superior mesenteric vein

Question 24

What is the purpose of the portal circulation?

Answer 24

To allow blood carrying recently digested chyme to be processed by the liver prior to entering the general circulation

Question 25

Where to the oesophageal veins drain?

Answer 25

Azygos system

Question 26

Why is knowledge of the lymphatic drainage of the GI tract important?

Answer 26

Spread of metastasising cancer cells

Question 27

What are the pre-aortic lymph nodes?

Answer 27

Coeliac, superior mesenteric and inferior mesenteric lymph nodes

Question 28

True or false: The pre-aortic lymph nodes drain into one another, from below upwards

Answer 28

True

Question 29

The coeliac lymph nodes drain into which channel? Where does it run and empty its contents?

Answer 29

Cisterna chyli

Empties into thoracic duct

Question 30

Where does lymph from the rectum go?

Answer 30

Follows the middle rectal artery to the internal iliac lymph nodes

Question 31

What are Peyer’s patches?

Answer 31

Areas of lymphoid tissue which are located within the walls of the small intestine

Question 32

In which layers of the gut wall are the intrinsic (myenteric) nerve plexuses located?

Answer 32

Muscularis propria, between the submucosa and the serosa or adventitia

Question 33

While most of the autonomic fibres to the gut travel via the coeliac plexus, parasympathetic fibres to the hindgut originate from __1__ and and travel via the __2__

Answer 33

1) sacral segments of the spinal cord

2) inferior hypogastric (pelvic) plexus

Question 34

The coeliac plexus receives its parasympathetic input from what nerves?

Answer 34

Vagus nerves

Question 35

The coeliac plexus receives sympathetic input from what nerves?

Answer 35

Splanchnic nerves

Question 36

The splanchnic nerves arise from __1__ and enter the abdomen via the __2__

Answer 36

1) sympathetic chain

2) aortic hiatus

Question 37

Where would a patient feel pain referred from the foregut?

Answer 37

Epigastric region

Question 38

Where would a patient feel pain referred from the midgut?

Answer 38

Umbilical region

Question 39

Where would a patient feel pain referred from the hindgut?

Answer 39

Hypogastric or pubic region

Question 40

To which area is pain from the appendix referred?

Answer 40

Umbilical region

Question 41

Why might pain from the gallbladder be referred to the shoulder?

Answer 41

If the pain reaches the diaphragm, then nerves C3-5 will be involved. This is the dermatome of the shoulder

Question 42

What structure is found in the free edge of the falciform ligament?

Answer 42

Ligamentum teres (vestige of umbilical vein)

Question 43

What structures pass through the porta hepatis?

Answer 43

Hepatic ducts (left and right)

Hepatic portal vein

Hepatic arteries

(NOT hepatic veins)

Question 44

How many hepatic veins are usually found in the liver? Where do they drain into?

Answer 44

Usually 3

Drain into IVC

Question 45

What structures provide anchoring for the liver?

Answer 45

Hepatic veins

Falciform ligament

Triangular ligament

Question 46

What structures run in the free edge of the lesser omentum?

Answer 46

Hepatic artery (anterior left)

Bile duct (anterior right)

Hepatic portal vein (posterior)

Question 47

Where does the common bile duct run after it leaves the lesser omentum?

Answer 47

Posterior to the duodenum and head of pancreas, to form the hepatopancreatic ampulla with the main pancreatic duct

Question 48

What is the hepatopancreatic ampulla (of Vater) and where is the sphincter of Oddi?

Answer 48

Dilation where the bile duct and main pancreatic duct unite, it is surrounded by the hepatopancreatic sphincter (of Oddi). A smooth muscle sphincter so is under control of the ANS

Question 49

If a gallstone became lodged at the sphincter of Oddi, which other organ would be affected?

Answer 49

Pancreas

Question 50

Biliary obstruction can cause what symptoms? Why?

Answer 50

Jaundice, pale faeces, dark urine

Bile is reabsorbed into the bloodstream and deposited where the pressure is low (ie surface of the skin). Pale faeces are due to the lack of bile entering the GI tract and therefore colouring the faeces. As it is in the bloodstream it is filtered by the kidney darkening the urine.

Question 51

What is the blood supply of the gallbladder? Where does it come from?

Answer 51

Cystic artery, from right hepatic artery