Liver Flashcards
What is the liver surrounded by a capsule of
Connective tissue
The connective tissue surrounding the liver extends into it as highly branched septae. These septae outline what? What shape are they?
Hepatic lobules
Hexagonal
What is found between hepatic lobules?
Portal triads - hepatic artery, hepatic portal vein, bile duct
Hepatic acini - functional units
What do hepatocytes do?
Absorb molecules from Space of Disse
Secrete bile into bile canalicus (collecting ducts)
Describe the pathway of bile from from hepatocytes
Hepatocytes secrete bile into bile canaliculus Flows into ductules Flows into ducts Flows into common bile duct Enters duodenum at Sphincter of oddi
How does bile move between the gall bladder and bile duct? (Via which duct?)
Cystic duct
Most of blood entering the liver is from which vessel? Some of blood is from which vessel? What happens to this blood?
Most from hepatic portal vein
Some from hepatic artery
Mixes as they flow into sinusoids
what endothelium have sinusoids got? What are they surrounded by?
Fenestrated
Macrophages
Describe the blood flow away from the liver
Sinusoids empty into central veins
Central veins joint to form hepatic veins
Hepatic vein enters into caudal VC
How does the liver deal with toxic/harmful compounds? WHich coenzyme is involved?
Detoxifies them into less toxic compounds
Degrades them via coenzyme cytochrome P450
Describe the degradation of red blood cells and what haem is converted to
RBCs removed from blood by macrophages in spleen and liver
Degraded to yield haem from haemoglobin
Haem converted to biliverdin, then bilirubin and bound to albumin
What happens to bilirubin before it is excreted into bile?
It is conjugated with glucoronic acid
What are the names of two bile ligaments? How are they produced?
Biliverdin
Bilirubin
Conversion from haem, removed from haemoglobin
How are bile pigments excreted?
Bile bacteria remove glucoronic acid from bilirubin and metabolise stercobilin- gives faces brown colour
What are the functions of bile?
Produce micelles for lipid absorption
Promote hydrolysis of lipases
Exit route for waste products and drugs
What is the composition of bile?
Water HCO3 Bile pigaments Bile acid Cholesterol Phospholipids
Where is bile stored? Which animals do not have this? Do they have a sphincter of oddi?
Gall bladder
Not horses
Yes but inactive - continuous bile flow
Where does the gall bladder empty vile into? Via which structure, and what controls this?
Duodenum
Major duodenal papilla
Sphincter of Oddi
What are the 2 major bile acids synthesised from cholesterol in the liver? Are they lipophobic or hydrophobic?
Cholic acid
Chenodeoxycholic acid
Hydrophobic
How are bile acids made water soluble?
Conjugation with glycine or taurine
How are secondary bile acids produce? Where does this take place
Primary bile acids metabolised by bacteria to form secondary bile acids
Terminal ileum
What is enterohepatic circulation? How does this happen?
Recycling of bile acids
Absorbed from terminal ileum via AT
Returned back to liver via hepatic portal vein and absorbed from bloodstream by NTCP
Which nervous system is responsible for bile secretion? Which nerve?
Parasympathetic
Vagus nerve
Which hormones/substances regulate bile secretion?
CCK
Secretin
Bile salts returning from enterohepatic circulation
Bile secretion is decreased in between meals. Explain how the gall bladder does this
Gall bladder relaxes
Contract Sphincter of Oddi
Decreased enterohepatic circulation
Bile is stored
What does the hormone CCK do? Which hormone inhibits CCK secretion?
Released into duodenum in response to H+
Secretes HCO3-
VIP
What does the hormone secretin do?
Increase enzyme secretion and gall bladder contractions
Released into duodenum in response to fat/protein metabolites
Some hepatic dysfunctions are reversible. What might cause these problems?
Infection
Poisoning - acute or chronic
Tumours
What might hepatic diseases affect in the liver function?
Metabolic functions
Detoxificaiton
enterohepatic circulation
What are the clinical signs of hepatic problems?
Depression Decreased appetite Lethargy Vomiting/diarrhoea Polydypsia/polyuria Hepatomegaly or microhepatica Jaundice Bleeding
jaundice makes the skin appear yellow. What molecule increase causes this?
Increased levels of bilirubin
What is cholestasis?
Reduction/stop of bile flow
What is Porto-systemic shunts? Why might this happen
Blood flow bypasses liver
Congenital or acquired (hypertension)
