Liver, Gallbladder, Pancreas & Spleen

Question 1

The pancreas is retro or interperitoneal?

Answer 1

Retroperitoneal

Question 2

What are the exocrine secretions of the pancreas?

Answer 2

• Exocrine: pancreatic juice – released into descending duodenum
o Alkaline secretion containing many digestive enzymes
o Exocrine cells secrete pancreatic juices into small ducts that ultimately form two larger ducts; the pancreatic duct & the accessory duct.

Question 3

What are the endocrine secretions of the pancreas

Answer 3

• Endocrine: insulin & glucagon for regulation of blood sugar concentration

Question 4

Anatomy of the pancreas. Where is it located?

Answer 4

• Located at vertebral levels L1-L2, in the umpilical & epigastric regions (tail extends into left hypochondium)
• Parts: head, neck, body, tail, uncinate process
o The head of the pancreas lies within the C shaped concavity of the duodenum ⇒ head of pancreas surrounded by duodenum
o Projecting from the lower part of the head is the uncinate process, which passes posterior to the superior mesenteric vessels
o Body of the pancreas is elongated & extends from the nec to the tail of the pancreas
o The tail of pancreas passes between layers of the splenorectal ligament

Question 5

List the anatomical relationships of the pancreas

Answer 5

• Anterior to pancreas: stomach (& if stomach is small ie haven’t eaten – SI, transverse & mesocolon may sit anterior to the pancreas)
• Posterior: blood vessels –
o abdominal aorta, splenic artery (may be slightly superior), renal vessels
o IVC, superior mesenteric vein, splenic vein, inferior mesenteric vein
• Implications in pancreatitis

Question 6

Pancreatic Ducts

Answer 6

• Main pancreatic duct joins the common bile duct at the hepatopancreatic ampulla (of Vater), which is surrounded by the Hepatopancreatic sphincter (of oddi)
• This enters the descending duodenum at the major duodenal papilla
• Gallstones may obstruct the opening, causing a backup of bile & pancreatic secretions => pancreatitis
o Gallstones form from bile salts
• The accessory pancreatic duct opens at the minor duodenal papilla

Question 7

What is the blood supply of the pancreas

Answer 7

• Pancreas is a foregut derivative, but at the junction of foregut & midgut
• Superior & inferior pancreaticoduodenal arteries from superior mesenteric artery
• Pancreatic aa from the splenic artery (from coeliac trunk)
• Supraduodenal artery to superior duodenum; from the gastroduodenal artery, from the common hepatic artery of the coeliac trunk
• Superior pancreaticoduodenal arteries => branch from gastroduodenal artery from common hepatic artery from coeliac trunk

Question 8

Explain the parasympathetic innervation of the pancreas

Answer 8

Parasympathetics
• Also called craniosacral division of the ANS
o Preganglionics either in cranial cavity or sacrum of spinal cord.
• For stomach the preganglionics are located in the medulla of the brainstem
• Neuron cell bodies have axons which exit the medulla & are conveyed by the vagus nerves (through neck, thorax & into abdomen) to the stomach
• In thoracic cavity, the vagus nerves form the oesophageal plexus.
o Left vagus nerve is on the anterior side & the right vagus nerve ends up mainly going to the posterior aspect of the oesophagus; collectively they form the oesophageal plexus & then the anterior & posterior vagal trunks (on either side of the oesophagus)
• The vagal trunks exit through the diaphragm with the oesophagus at T10
• The vagus nerve runs along the oesophagus & supplies both the midgut & foregut.
• Vagal trunks synapse as intramural ganglion – they can synapse directly onto smooth muscle or glands, or can synapse onto enteric nervous system (ENS). They may also have gastric branches.

Question 9

Explain the sympathetic innervation of the pancreas

Answer 9

• Also known as the thoracolumbar division of the ANS
o Preganglionic cell bodies in the thoracic & upper lumbar regions: T1-12 & L1-2
• For stomach (foregut derivative) preganglionics mainly located in T6-T9, in the lateral horn of the gray matter of the spinal cord
• Through ventral root, then spinal nerve, then axons peel off to the grey & white rami communicantes (communicating nerves), leading into the sympathetic chain ganglion. But axons do not synapse in these ganglions, they pass through, so (long) preganglionic axons exit anteriorly forming the greater thoracic splanchnic nerve (T6-T9) which pierces the diaphragm with the oesophagus at T10.
• Greater thoracic splanchnic nerve synapses in coeliac ganglion (solar plexus)
• Postganglionic axons follow blood vessels to directly innervate smooth muscle, glands, or synapse with the ENS

Question 10

Explain afferent and direct irritation pain of the pancreas

Answer 10

• Pain afferents to T6-T9 spinal cord (may be referred to corresponding dermatomes - epigastric region) or in the high back (anterior to shoulder blades)
• Direct irritation of somatic nerves in the posterior abdominal wall at vertebral levels L1-L2 lumbar back pain
o The pancreas is at vertebral levels L1-2 so you can get localized pain in this area as well

Question 11

Pancreatic lymphatics

Answer 11

• Various pancreatic nodes, which also receive lymph from the stomach & duodenum
o i.e. inferior pancreatic, duodenal lymph nodes
• These go ⇒ coeliac & superior mesenteric nodes ⇒ intestinal lymph trunk ⇒ cysterna chyli ⇒ thoracic duct

Question 12

What are the functions of the SPLEEN

Answer 12

• Lies against the diaphragm in the area of rib IX to rib X. In the Left hypochondrium
• Lymphoid organ, eliminates old RBCs from circulation, converts haem to bilirubin (taken to liver => bile)

Question 13

What are the anatomical relationships of the spleen

Answer 13

o Anteriorly: Stomach
o Inferior notch: left colic/splenic flexure
o Posterior: left kidney, left lung (lower lobe), costodiaphragmatic recess
o Posterolateral: part of rib 8, ribs 9,10,11 cover the spleen
o Attached to the greater curvature of the stomach by the gastrosplenic ligament (contains short gastric & gastro-omental vessels)
o Attached to the left kidney by the splenorenal ligament (contains splenic vessels)

Question 14

Is the spleen intra or retroperitoneal?

Answer 14

• Intraperitoneal: gastrosplenic, splenorenal ligaments from the hilar region
o At the hilar region the peritoneum reflects off (contains short gastric & gastro-omental vessels – ie left gastroepiploic)
o Where it reflects off the stomach = gastrosplenic ligament (contains
• Spleen develops within dorsal mesogastrium (dorsal mesentery of stomach)

Question 15

What are the digestive functions of the LIVER

Answer 15

Digestive Functions
• Produces bile (fluid, ions, bicarbonate to neutralize), which aids in digestion & absorption of lipids (fats) by emulsifying them (0.5-1um) and solubilizing the digestion products in micelles (approx. 5-10nm), bilirubin (breakdown of haem from RBC) and neutralizes acidic chyme

Question 16

What are some of the OTHER functions of the liver

Answer 16

• Metabolises haeme (from haemoglobin) to bile pigments, which are excreted in bile
• Synthesises many plasma proteins including albumin & globulins (except immunoglobulins) which are the main contributors to plasma oncotic pressure.
• Also synthesizes most clotting factors, and VLDLs (lipoprotein)
• Stores & breaks down glycogen to help regulate blood glucose levels
• Metabolises amino acids & fats
• Stores iron, vitamin B12, A, D & other micronutrients
• Chemical modification of various toxins including drugs. This generally makes the compounds more soluble, to promote excretion by the kidney

Question 17

What is the surface anat of the LIVER

Answer 17

• Quadrants: right upper, extends into left upper.
• Regions: right hypochondrium, epigastrium
• Ribs:
o liver comes up as high as the fifth rib anteriorly (ie to the xiphisternal joint)
o The liver (inferior surface) is near the R costal margin laterally & inferior to it medially – can palpate finger along the edge of liver
• Posteriorly: vertebral levels T9-L2
• Physical exam: palpate, percuss

Question 18

What are the lobes and segments of the liver called?

Answer 18

• Segments are supplied by portal triad branches
o Important for surgeon (resecting)
• Lobes: right, left, quadrate & caudate lobes

Question 19

Explain the LIVER SURFACES

Answer 19

• Diaphragmatic & Visceral surfaces
o Diaphragmatic surface in the anterior, superior & posterior directions
o Visceral surface in the inferior direction (can separate the liver into four lobes)
• H-shaped attachment on visceral surface separates liver into 4 lobes
o IVC
o Hepatic portal vein, hepatic artery, bile duct
o Gallbladder
o Ligamentum venosum (remnant ductus venosus)
o Ligamentum teres hepatis = round ligament of liver (remnant of umbilical vein)
o Porta hepatis structures

Question 20

Explain the peritoneum and the LIVER

Answer 20

• Falciform, coronary, and triangular ligaments
o Free edge of falciform ligament = ligamentum teres hepatis
• Lesser omentum – hepatogastric & hepatoduodenal ligaments
• Liver develops within ventral mesogastrium, which forms the falciform ligament & lesser omentum
• Posteriorly the liver is directly in contact with the diaphragm – here you get a change from visceral to parietal peritoneum.
o Subphrenic spaces of peritoneal cavity – between diaphragm & liver
o Hepatorenal recess

Question 21

What is the porta hepatis of the liver

Answer 21

• The visceral surface of the liver is covered with visceral peritoneum, except in the fossa for the gallbladder and at the porta hepatis (gateway to liver)
• Porta hepatis contains:
o Hepatic portal vein & hepatic artery (both bringing blood to liver)
o R&L hepatic ducts, Common hepatic duct, cystic duct & common bile duct (bringing bile from liver ⇒ gallbladder ⇒ duodenum)
o Nerves & lymphatic vessels
• Surrounded by the lesser omentum
• Anterior to epiploic foramen (opening between greater & lesser sacs)

Question 22

Explain the anatomical relationships of the liver

Answer 22

• Related to the visceral surface
o Stomach, gallbladder, kidney, adrenal medulla, right colic flexure, superior duodenum
• Diaphragmatic surface
o Superior to the liver
o Right lung, Heart (RA – IVC, SVC)
o Immediately left = stomach
o Posterior to liver = lungs, inferiorly = costodiaphragmatic recess

Question 23

What is the surface anatomy of the liver

Answer 23

• Quadrants: right upper, extends into left upper.
• Regions: right hypochondrium, epigastrium
• Ribs:
o liver comes up as high as the fifth rib anteriorly (ie to the xiphisternal joint)
o The liver (inferior surface) is near the R costal margin laterally & inferior to it medially – can palpate finger along the edge of liver
• Posteriorly: vertebral levels T9-L2
• Physical exam: palpate, percuss

Question 24

What is located on the surfaces of the liver

Answer 24

• Diaphragmatic & Visceral surfaces
o Diaphragmatic surface in the anterior, superior & posterior directions
o Visceral surface in the inferior direction (can separate the liver into four lobes)
• H-shaped attachment on visceral surface separates liver into 4 lobes
o IVC
o Hepatic portal vein, hepatic artery, bile duct
o Gallbladder
o Ligamentum venosum (remnant ductus venosus)
o Ligamentum teres hepatis = round ligament of liver (remnant of umbilical vein)
o Porta hepatis structures

Question 25

Gallbladder: FUNCTIONs

Answer 25

• Storage & concentration of bile, release via cystic duct ⇒ common bile duct ⇒ hepatopancreatic ampulla ⇒ duodenum
o Storage & concentration of bile between meals; released on demand – stimulated by CCK (from duodenum)
• Fundus, body, neck regions

Question 26

ANatomical relationships of the gall bladder

Answer 26

o Above = liver
o Beneath = transverse colon
o Left of it = superior duodenum

Question 27

Describe the surface anatomy of the fundus of the gall bladder

Answer 27

• Surface anatomy of fundus:
o Intersection of transpyloric & midinguinal lines
o at tip of right 9th costal cartilage (where it articulates with 8)
• Gallbladder can become inflamed, get gallstones ⇒ swelling & pain

Question 28

Explain the arterial blood to liver, gallbladder and ducts

Answer 28

• Branches of coeliac artery (all foregut):
o Common hepatic artery ⇒ proper hepatic artery ⇒ L/R hepatic artery
o R hepatic artery ⇒ cystic artery (supplies gallbladder – within the cystohepatic triangle)
• Cystohepatic triangle = bounded by cystic duct, common hepatic duct, liver
• Variations common (important in cholecystectomy)

Question 29

Blood supply of the liver: Portal venous system

Answer 29

• Liver receives venous blood from GIT, pancreas & spleen via the hepatic portal vein
o From splenic, inferior mesenteric & superior mesenteric veins
• Hepatic artery & hepatic portal vein blood mixes in liver sinusoids
• Portal system is anatomic basis of:
o Pharmacological first pass effect: taking drugs orally, they are absorbed in the GIT then the liver is the first stop for metabolism
o GI cancers often metastasise to the liver
• Liver sinusoids drain ⇒ central veins ⇒ hepatic veins (right, middle, left) to IVC

Question 30

Portal caval anastomasoses

Answer 30

• Portal venous system has no valves – hence potentially, blood can reverse its direction of flow.
• Anywhere with retroperitoneal organs
• Portal Hypertension; as a result of this, the portal-caval vessels may become enlarged in order to decrease hepatic portal venous pressure by shunting blood into the systemic circulation