Portal Venous System/Liver Flashcards
The portal venous system drains what structures?
GI tract, spleen, pancreas, and gallbladder
All nutrients except what kind pass through the portal system to the liver?
Fats
What picks up the fats that bypass the liver?
Lymphatics of the small intestine (lacteals)
What is the pathway of the portal venous system?
Abdominal organs (GI tract, spleen, pancreas, gallbladder) –> Tributaries of the portal vein –> Portal vein which divides into right and left branches –> liver sinusoids –> Inferior vena cava via the hepatic veins
What is unique about the portal vein?
It has right and left branches, while veins usually have tributaries
What does the caval venous system drain?
Everything the portal system does not
What is the blood flow of the caval venous system?
Body wall and organs –> tributaries of the superior and inferior vena cava –> superior and inferior vena cava
What forms the portal vein?
Formed behind the head of the pancreas by the union of the splenic and superior mesenteric vein
What are the tributaries of the portal vein?
Splenic vein, superior mesenteric vein, left gastric vein, paraumbilical veins
What are the tributaries of the splenic vein?
Short gastric veins, left gastro-omental vein, pancreatic veins, inferior mesenteric vein
What are the tributaries of the inferior mesenteric vein?
Left colic vein, sigmoid veins, superior rectal vein
What forms the inferior mesenteric vein?
Sigmoid vein and superior rectal vein
What are the tributaries of the superior mesenteric vein?
Jejunal and ileal veins, ileocolic vein, right colic vein, middle colic vein, right gastro-omental vein, pancreaticoduodenal veins
What vein of the portal system accompanies the ligaments teres to the umbilicus?
Paraumbilical veins
What is cirrhosis of the liver?
A condition characterized by the destruction of hepatic cells and their replacement by fibrous tissue and fat
What is unique about the paraumbilical veins?
Only tributary of the portal vein that doesn’t accompany artery of the same name
How does portal hypertension occur with cirrhosis of the liver?
The liver becomes nodular and hard, therefore constricting the portal vein at the porta hepatis
What are the causes of cirrhosis of the liver?
Alcoholism, hepatitis, chronic obstruction of the bile duct, or congestive heart failure
What is portal hypertension?
Abnormal elevation of pressure within the portal system, often due to cirrhosis of the liver
What vein is compromised in portal hypertension?
Portal vein
What happens to blood flow during portal hypertension?
Due to the portal system’s lack of valves, the blood flow is reversed and bypasses the liver leading to back-ups in the caval system where portal-caval anastomoses occur
What happens to these portal-caval anastomoses during back-ups due to portal hypertension?
Veins can become varicose and may rupture
What are varicose veins like?
Dilated, tortuous, and thin-walled
What are the three sites of portal-caval anastomoses?
Distal esophagus, around the umbilicus, rectum/anal canal
What veins make up the portal-caval anastomosis of the distal esophagus?
Caval = esophageal, Portal = left gastric
What veins make up the portal-caval anastomosis around he umbilicus?
Caval = superficial veins of the anterior abdominal wall, Portal = paraumbilical
What veins make up the portal-caval anastomosis of the rectum and anal canal?
Caval = middle and inferior rectal, Portal = superior rectal
What is the obstructive sign of portal hypertension at the distal esophagus’s portal-caval anastomosis?
Esophageal varices
What is the obstructive sign of portal hypertension at the portal-caval anastomosis around the umbilicus?
Caput medusae
What is the obstructive sign of portal hypertension at the rectum/anal canal’s portal-caval anastomosis?
Hemorrhoids
What is the worst case scenario for esophageal varices?
They can hemorrhage with severe, often fatal, bleeding
Are hemorrhoids diagnostic of portal hypertension when present alone?
NO.
What is the largest visceral organ and the largest gland in the body?
Liver
What are the functions of the liver?
Bile secretion; metabolism of macronutrients; storage of glycogen, vitamins, and iron; detoxification
What is the function of bile?
Fat emulsification
What surface of the liver is superior and convex?
Diaphragmatic surface
What surface of the liver is inferior and concave
Visceral surface
What separates the diaphragmatic and visceral surfaces of the liver?
A sharp, inferior border
What does the porta hepatis contain?
Common hepatic duct (right), hepatic artery proper (left), portal vein (behind)
What significant structure does NOT pass through the porta hepatis?
Inferior vena cava
What lobe of the liver contains the gall bladder in a fossa on its visceral surface with the inferior vena cava lying posterior to it?
Right lobe
What lobe of the liver lies between the right and left lobes and anterior to the porta hepatis with the gall bladder to its right?
Quadrate lobe
What lobe of the liver lies between the right and left lobes and posterior to the porta hepatis?
Caudate lobe
What lobe of the liver lies to the left of the falciform ligament and is small than the right lobe?
Left lobe of the liver
What is jaundice?
Yellow discoloration of the skin, sclera, and mucous membranes due to the release of bilirubin into circulation
What is often the cause of jaundice?
Liver damage
Where would the functional division of the liver be made?
To the right of the falciform ligament
What hepatic segments lie in the left function half of the liver?
I-IV
What hepatic segments lie in the right functional half of the liver?
V-VIII
What is the area of the liver that is uncovered by visceral peritoneum?
Bare area
Where is the bare area of the liver located?
Posterior aspect of the diaphragmatic surface
What sits on the bare area of the liver?
Diaphragm
What important venous structure lies within the bare area?
Inferior vena cava
What ligament connects the liver to the diaphragm and anterior abdominal wall?
Falciform ligament
What ligament is the splitting of the falciform ligament as it passes posteriorly along the diaphragmatic surface of the liver?
Coronary ligament
What are the borders of the bare area?
Superior and inferior layers of the coronary ligament
What ligaments are formed at the junction of the superior and inferior layers of the coronary ligament on each side?
Right and left triangular ligaments
What ligament forms the free edge of the falciform ligament?
Ligamentum teres
The ligamentum teres is a remnant of what structure?
The obliterated umbilical vein
What ligament is located between the left and caudate lobes?
Ligamentum venosum
The ligamentum venosum is a remnant of what structure?
The ductus venosus
What ligament covers the inferior vena cava within the bare area of the liver?
Ligament of the inferior vena cava
The fissures of the liver form what shape on its visceral surface?
An H
What fissure is located between the left lobe and quadrate lobe?
Fissure for the ligamentum teres
What issue is located between the left lobe and caudate lobe?
Fissure for the ligamentum venosum
What fossa is located between the right lobe and the quadrate lobe?
Fossa for the gallbladder
What fissure is located between the right lobe and the caudate lobe?
Fissure for the inferior vena cava
What forms the crossbar of the H-shape of fissures on the liver?
Porta hepatis
What makes up the liver’s dual blood supply?
Portal vein and hepatic artery
What is the innervation of the liver?
Autonomic and pain fibers are from the hepatic plexus which is an extension of the celiac plexus
The portal vein makes up what percentage of the liver’s blood supply?
75-80%
The hepatic artery makes up what percent of the liver’s blood supply?
20-25%
