Liver structure and function Flashcards
Liver anatomy
Greatest organ in the human body- 1.4 kg
Divided into two big lobes: right>left
and two smaller lobes: caudate> quadrate
Covered in connective tissue and visceral peritoneum in all points except the BARE AREA on the diaphagmatic surface
What is the PORTA and where is it situated
it is the point of entry of lymphatics/ blood vessels to the liver
it is situated on the inferior surface
What happens at the PORTA?
the connective tissue separates out into septa which divide the liver into hexagonal lobules
what is found at the corner of the hexagonal lobules?
The portal train:
hepatic portal vein / hepatic artery- carry blood in
hepatic duct- carries bile out
what is found at the centre of each lobule? and where does this drain
the central vein- drains into HEPATIC VEINS INTO IVC
what are the liver cells called at what do they make up?
liver cells are called hepatocytes
they group up to form hepatic cords
what is found between hepatocytes?
hepatic sinusoids
Bile cannuliculi
What happens to blood in the liver
- Blood from the hepatic portal vein mixes with blood from the hepatic artery and passes into the hepatic sinusoids
- As blood passes through the hepatic sinusoids it is filtered by the hepatocytes
- once filtered by the hepatocytes it passes into the hepatic vein and from there into the IVC
- Bile produced from the hepatocytes passes into the cannuliculi and from there into the hepatic ducts
Describe the differences between blood in the hepatic artery and portal vein
hepatic portal vein: 02 poor- nutrient rich
hepatic artery: 02 rich, nutrient poor
What the functions of the hepatocytes?
-Storage: Glycogen Iron Copper -Synthesis: Glucose, glycogen Bile -Detoxification : Breaks down NH3 into urea Breaks down insulin and glucagon -Immunological functions
What is bile made of?
- cholesterol
- bile acids
- bile pigments
- bicarbonate ions
- lecithin
- toxic metals
which components of bile are synthesised in the liver? and what do they do?
cholesterol
bile acids
lecithin
they break down fat
which components of bile and secreted by hepatocytes
bile acids cholesterol lecithin bile pigments toxic metals
where is bicarbonate in bile secreted from?
duct cells of the pancreas
What is bilirubin
Main bile pigment- extracted from old/damaged erythrocytes
Why is bile yellow?
bilirubin extracted from old blood and secreted into bile by hepatocytes
why are faeces brown?
in the large intestine- bacterial enzymes modify bilirubin
why is urine yellow?
Bilirubin is not broken down by bacterial enzymes- becomes reabsorbed and as it is yellow it turns urine yellow
What are bile salts?
They are produced by the liver daily from cholesterol
They are mixed with Taurine/Glycine to increase solubility
Used to break down fat
How are bile salts recycled?
Enteropathic circulation
Liver- common bile duct-Duodenum- common hepatic vein- liver
Layers of the gall bladder
- mucose
- muscularis- smooth
- serosa
how is secretion of bile controlled in the gall bladder?
Sphincter of Oddi.
When it relaxes (e.g. in the presence of Fat)- bile and pancreatic juice released into the duodenum
When it contracts- bile is concentrated
