Anatomy of the biliary tract and spleen

Question 1

The biliary tree

Answer 1

Pathway of bile moving from the liver to the duodenum:

1. Sectoral ducts of the liver (R and L)
2. Left and right hepatic duct.
3. Common hepatic duct
   - cystic duct connects from gallbladder
4. Common bile duct
   - connects to main pancreatic duct
5. Duodenum
   - bile is drained into duodenum via the major and minor duodenal papilla

Question 2

Major and minor duodenal papilla

Answer 2

Major duodenal papilla:
The opening of the common bile duct + main pancreatic duct (ampulla of Vater) into the descending duodenum.
- surrounded by the sphincter of Oddi.

Minor duodenal papilla:
Opening of the accessory pancreatic duct into the duodenum.

Question 3

Intrahepatic bile duct

Answer 3

The biliary system inside the liver: sectoral ducts.

Ductules collect duct from canaliculi and drain into larger bile ducts.

Each intrahepatic duct runs with a branch of the portal vein and hepatic artery.

This then carries bile into the right and left hepatic duct.

Question 4

Ductules and larger bile ducts

Answer 4

Ductules drains bile from hepatocytes.
- Contain thin walls made from cuboidal epithelium

Larger bile ducts drain bile from the ductules and towards to hepatic duct:

• Contains loose connect tissue
• Columnar epithelium

Question 5

Duct wall of the extrahepatic bile ducts

Answer 5

Contains:

• Dense fibrous connective tissue with smooth muscle
• The lumen is lined with columnar epithelium

Question 6

Ampulla of Vater

Answer 6

The joining of the common bile and the main pancreatic duct at the major duodenal papilla.

It drains bile from the two ducts into the duodenum.

Question 7

Sphincter of Oddi

Answer 7

Sphincter located at the major duodenal papilla.

Controls the flow of bile and pancreatic juices from the ampulla of Vater into the descending duodenum.

Question 8

Blood supply of the bile duct walls

Answer 8

Branches of the cystic arteries.

Question 9

Functions of the gallbladder

Answer 9

Stores and concentrates bile

Produces and selectively reabsorbs bile salts.

Excretes mucus and cholesterol

Question 10

Anatomy of the gallbladder

• sections
• location and its surroundings
• blood supply
• structure of the all

Answer 10

Divided into three sections: Fundus, body and neck.

Location: lies in the visceral fossa of the right lobe in the liver.

• duodenum posteriorly
• right lobe anteriorly
• quadrate lobe on the left
• porta hepatis superiorly

Blood supply:
Cystic artery- from right hepatic artery

Wall:
Lined with columnar epithelium for secretions.
Smooth muscle- allows peristalsis

Question 11

Structures in the free edge of the lesser omentum

Answer 11

Contains the portal triad:
Portal vein
Hepatic artery proper
Common bile duct

Question 12

Mechanism of releasing bile from the gallbladder

Answer 12

1. Detection of proteins and fats in the duodenum causes an increase in the secretion of CCK (cholecystokinin)
2. CCK is released in the blood and travels to the gallbladder via cystic artery.
3. CCK stimulates the smooth muscle in the muscularis propia layer to contract and force bile out of the gallbladder.
4. Bile flows via cystic duct into the common bile duct where it fuses with the main pancreatic duct at the ampulla of Vater.
5. Bile is released into the duodenum via the major duodenum papilla through the relaxation of the sphincter of Oddi.
6. This allows fat to be emulsified in the duodenum.

Question 13

Arterial supply of the pancreas [3]

Answer 13

Supplied by branches of the celiac trunk (CT) and the superior mesenteric artery (SMA).

• Pancreatic artery: from splenic artery—> from CT
• Pancreaticoduodenal artery: from SMA. Supplies the head.
• Gastroduodenal: branch from common hepatic artery—> connects to the pancreaticoduodenal

Question 14

Venous drainage of the pancreas

Answer 14

Pancreatic veins drain into the splenic and superior mesenteric veins.

Ultimately drains into the hepatic portal vein.

Question 15

Nervous supply to the pancreas

Answer 15

Sympathetically:
Coeliac ganglia

Parasympathetically:
Vagus nerve

Question 16

Anatomy of the pancreas

• Sections
• Location

Answer 16

Divided into: 
Head- at the duodenum
Neck- anterior to the superior mesenteric 
Body- posterior to stomach
Tail- extending towards the spleen.

Question 17

Pancreatic duct system

Answer 17

Duct of Wirsung/ main pancreatic duct runs through the whole pancreas.
- Collects exocrine secretions from smaller ducts throughout the pancreas.

Duct of Wirsung drains into the ampulla of Vater where it connects with the common bile duct.

This then drains into the major duodenal papilla.

Duct of Santorini/ accessory pancreatic duct drains into the duodenum at the minor duodenal papilla.

Question 18

Functions of the pancreas

Answer 18

Exocrine:
Secretes pancreatic juice via duct of Wirsung, which contain digestive enzymes.
- Secreted from acini

Endocrine:
Islet of Langerhans cells secrete hormones
- contains cuboidal epithelium

Question 19

Anatomical features of the spleen.

Answer 19

Location:
- Left hypochondrium (between ribs 9 and 11)

Indentations:

• Stomach
• Left kidney
• Left flexure of the colon

Red pulp = venous sinuses with red blood cells
White pulp = lymphatic tissue
CT capsule- prevents distension

Question 20

Arterial supply of the spleen

Answer 20

Splenic artery- branch of the celiac artery

Question 21

Venous drainage of the spleen

Answer 21

Splenic vein- drains to the hepatic portla vein

Question 22

Nervous supply to the spleen

Answer 22

Splenic plexus:

Sympathetic:
Celiac nerve plexus

Parasympathetic:
Vagus

Question 23

Functions of the spleen

Answer 23

Removes defective red blood cells.

Stores platelets

In fetus- produces blood cells.

Question 24

Visceral pain

Answer 24

Pain from the abdominal viscera is felt via abdominoplevic splanchnic nerves.

Pain from the foregut passes through the celiac ganglion.

The afferent fibers enter the spinal cord at the same level of superficial somatic fibers- hence why referred pain.