Liver Flashcards
(32 cards)
Bile from liver can be hydrolysed by bacteria flora in GI tract into…?
Either
Urobilinogen which gets re-absorbed into blood to liver// excreted via kidneys
Or
Stercobilin& urobilin which are brown coloured and see excreted via faeces
What’s the three main roles of liver in process of detoxification?
Modify or inactive hormones
Remove foreign toxic substances
Convert ammonia to urea
Phases of Bio-transformation of drug/poisons (xenobiotics: substances not normally found in body)
Phase 1: modification by oxidation reduction or hydrolysis to reduce toxicity
Phase 2: conjugation to another molecule to increase solubility to facilitate excretion form body (toxins are insoluble)
What are the chemicals that often conjugate to drugs/toxin?
Acetate, glururonic acid or sulphate
What conjugated with paracetamol?
Cytochrome P450 –> N-acetyl p benzoquinone imine (NAPBQI) which is highly toxic ( product is more toxic than starting drug!)
What’s a bile pigment? Is it soluble or not? What’s it’s purpose?
They are breakdown product of haem portion of haemoglobin (from senescent RBC, broken down by spleen, phagocytes)
Not soluble, need to be conjugated to glucorinic acid in liver
Responsible for yellow colour of bile
Bile duct is lined by what cell
Hepatocytes
Portal field (portal triad) is composed of?
Hepatic portal vein, hepatic artery, bile duct
The flow of blood in liver
Portal vein and hepatic artery –> sinusoid –> central vein –> vena cava to heart
Is flow of bile same direction as flow of blood?
No, counter current flow
How does liver generate bile?
Na+ (bile salt )co transport (from sinusoid blood to hepatocyte)
Active transport of bile salt (from hepatocyte to bile canaliculi)
With sodium and water from bile canaliculi
Blood sinusoid is lined by?
Single layer of fenestrated endothelial cells, small cells normal aggregated into groups called liver sieve plates
Role of Kupffer cells
Also known as stellate macrophage.
Inside the lumen of sinusoid, adhere to endothelial cells.
Host defence function
What are the 3 plasma protein that liver secrets? AGC
Their roles?
Albumin (transport lipids and steroid hormones)
Globulin (alpha, beta globulins, same role)
Clotting factor (fibrinogen, prothrombin)
Where in blood, and in muscle does iron bind to? And what is it stored as?
In red blood cells, iron binds to haemoglobin
In muscle, iron binds to myoglobin, iron containing enzymes
Stored as ferritin
As RBC senescent, iron is transferred by what plasma protein?
Or stored as what in where?
Transferrin
Stored as ferritin in liver
Iron in blood can be stored, transferred by transferrin, and what else?
Erythropoiesis- production of RBC
What’s liver’s endocrine function?
Releases insulin like growth factor (IGF) 1 and 2
What are the functions of IGF?
Potent growth promoting effect
What’s the Ph of hepatic bile?
7-8 isotonic
What are the 4 components of bile
- Bile salts
- Bile pigments
- Cholesterol
- Lecithin
Describe the process which bile salt formed?
Bile acid conjugated with amino acid like glycine form water soluble bile salt
What’s the main role of bile salts?
Hydrophilic and hydrophobic regions form micelles, emulsification of fats
Where does 95% od the bile salt go from intestine? Where does the 5% go?
Recycled back to liver via heptic portal vein
Lost in faeces
