Liver Structure and function Flashcards
List the functions of the liver (6)
Amino acid, carbohydrate and lipid metabolism
Storage of proteins, glycogen, vitamins and metals
Plasma protein and enzyme synthesis
Detoxification
Production of bile
Immune functions
In what region of the abdomen is the liver found in?
Right upper quadrant
List the lobes of the liver
Right
Left
Cuadate
Quadrate
Caudate – located on ____ aspect of the visceral surface
Quadrate – located on ____ aspect of visceral surface
Caudate = upper Quadrate = lower
what are the parenchymal cels fo the liver called
hepatocytes
hepatocytes are arranged into ____?
lobules
Each lobule is _____-shaped as is drained by a _____.
hexagonal
central vein
What structures make up the portal triad and where are they found?
Arteriole (branch of hepatic artery entering liver)
Venule (branch of hepatic portal vein entering liver)
Bile Duct (branch of bile duct leaving the liver)
They are found at the 6 edges of each lobule
At what anatomical area do these structures enter/leave the liver?
These all enter/exit the liver at the “porta hepatis”. Porta = gateway
what are the 2 distinct sources of blood supply to the liver ?
what percentage of the blood supply does each source make up?
What areas do they both supply?
Hepatic artery (30-40%) - supplies non-parenchymal structures Hepatic Portal Vein (60-70%) - supplies the liver parenchyma
What type of blood does each blood source supply to the liver?
Hepatic artery - Oxygenated blood
Portal vein - Nutrient-rich, partially deoxygenated blood
What are connecting sinusoids?
vascular channels that receive blood from the hepatic artery and portal vein at the periphery of lobules and deliver it to central veins
Sinusoids have a ______ ______ cell lining and are flanked by plates of _________
fenestrated endothelial
hepatocytes
Venous drainage of the liver is achieved via ?
hepatic veins
describe the passage of venous blood out of the liver
Central veins form collecting veins which then combine to from multiple hepatic veins. These hepatic veins open into the inferior vena cava.
What is the area called that separates Hepatocytes from sinusoids ?
Space of Disse
what feature do Hepatocytes have that extend into the Space of Disse?
Microvilli
What do hepatocytes do?
They exchange material with blood at sinusoidal surface
What are the 3 types of surface found on hepatocytes?
- Sinusoidal
- Intercellular
- Canalicular
What are the 2 ways in which sinusoids are different to normal capillary endothelium?
o Fenestrated (have holes in them) o Lack a complete basement membrane
list the 5 types of parenchymal liver cells
Hepatocytes Endothelial cells Kupffer cells Perisinusoidal (aka Ito) cells: Liver-associated lymphocytes
what are Kupffer cells a form of? what do they do?
form of macrophages
They are involved in phagocytosis
describe Ito/perisinusoidal/stellate cells and where are they found?
fat-storing cells found in perisinusoidal space (Space of Disse)
what is the Glisson’s capsule?
A thick, fibrous, INNER layer that covers the liver
What is the there layer that surround the liver besides Glisson’s capsule?
Outer serous layer derived from peritoneum
What is parenchymal reticulin made up of? where is it found?
made up of type 3 collagen
found around the central hepatic vein
supports parenchymal tissue of liver
List the parts of the biliary system
Bile canaliculi
Bile ductules
Bile ducts
Describe the passage of bile once it has been secreted
Bile is secreted by hepatocytes and the bile canaliculi empty into a series of progressively larger bile ductules and ducts. These eventually become the Common Hepatic Duct.
List the contents of bile
- Bilirubin
- Bile acid/salts
- Mucin
what is jaundice caused by?
a build-up of bilirubin
Define cirrhosis
Cirrhosis is a diffuse and irreversible process resulting in architectural disturbance, characterised by nodules of hepatocytes separated by fibrosis
Describe the pathogenesis and possible causes of cirrhosis
Persistence of ‘injury-causing agent’ e.g. obesity, alcohol, virus, autoimmune disease
Damage to hepatocytes and progressive loss of liver cells,
Leads to:
Liver inflammation = (Fibrous) scarring
Hepatocyte regeneration =hyperplastic nodules
Architectural abnormality
Eventually irreversible & cirrhosis develops
List the possible complications of cirrhosis
Portal hypertension
Liver failure
Liver (hepatocellular) cancer
Describe the effects of liver failure
Altered intermediary metabolism e.g. impaired synthesis of urea and glycogen – could cause hypoglycaemia
Reduced albumin & other transport proteins
Coagulation disorders
Reduced complement so prone to infection
Jaundice
Altered xenobiotic metabolism e.g. drugs
Circulatory and endocrine disturbances
List causes of cirrhosis
Alcohol Non-alcoholic fatty liver disease • Obesity • High blood pressure • Diabetes Hepatitis B/C virus (B is most common) Autoimmune hepatitis Biliary disease Haemochromatosis (genetic condition where there is an overload of iron)
How does cirrhosis result in portal hypertension?
Cirrhosis increases resistance to blood flow through the liver
This increases pressure in portal circulation
what changes does portal hypertension cause?
Portal-systemic shunts and varices (enlarged, swollen veins)
Ascites (abnormal build up of fluid in abdomen)
Splenomegaly (enlargement of spleen due to increased pressure)
