Human Physiology Liver Flashcards
Where does most of the blood coming to the liver come from
Hepatic Portal Vein
Liver is a double blood supplied organ, what is the supply
Hepatic Portal Vein (From the stomach and the intestines)
Hepatic Artery ( From the aorta )
Modified Capillaries in the liver
Sinusoids
- Wider
- More Gaps
- No Basement Membrane
Liver Cells name
Hepatocytes
Walls of the sinosids are lined with ??
Kupfer Cells
- Fixed phagocytotic cells in the siosuids and engulf and break down damaged and old red blood cells.
Functions of the Liver
1) Removes Toxins
2) Synthesis of plasma proteins
3) Synthesis of cholesterol
4) Surplus of cholesterol is converted to bile salts (Synthesis of bile salts)
5) Regulation of nutrients
6) Storage of nutrients
7) Breakdown of Red Blood Cells
Example of negative feedback that takes place in the liver
Synthesis of cholesterol
How is iron stored in the liver
In specific protein called Ferrin
Erythrocytes Life Span
120 Days
Describe the Breakdown of Erythrocytes
Starts with phagocytosis of RBC, by Kupffer cells.
At the end of their life span, proteins in the plasma membrane become modified to make them recognizable.
These modified cells are taken up by the Kupffer cells in the sinusoids by phagocytosis and are broken down to their components.
What causes the feces to be colored
Bilirubin, that is released by the blood.
Bilirubin is released in the blood, taken up by hepatocytes and converted to bile pigment and enters the bile which i released into the duodenum. Gut bacteria convert this into another yellow pigment that colors the faces.
Describe Jaundice
Condition where the skin and whites of the eyes become yellow
Happens when the pigment bilirubin accumulates in the blood which is then deposited in tissues.
Causes of Juandice
1) Pre hepatic Jaundice
2) Intra hepatic Jaundice
3) Post hepatic Jaundice
Consequences of Jaundice
Adults
- Itchy skin
Children
- Particular parts of the brain can become damaged resulting in deafness and cerebral palsey
Why do newborns frequently develop jaundice
Breakdown of red blood cells happen much faster than in children and adults.
There may not be enough liver enzymes that process biliriburin
Hepatic Circulation occurs through
Simple Diffusion
Whats the core of the liver functions
Liver functions to process nutrients absorbed from gut, hence regulating the body’s metabolic processes
What is liver composed of
Liver Lobules
Reasons to why sinusoids are used
Increased permeability thus allowing larger molecules such as proteins to enter and leave the bloodstream.
This is made possible due to its incomplete discontinuous basement membrane
and large intracellular gaps
Examples of nutrients stored within the Liver
A, D, glycogen, iron
Small intestine to Liver connected by
Hepatic Portal Vein
Carbohydrate Metabolism in the liver
Excess glucose in bloodstream stores as glycogen
When blood glucose levels fall, the liver breaks down glycogen into glucose to export it to body tissues.
When hepatic glycogen reserves become exhausted, liver synthesizes glucose from other sources such as fats.
DONE VIA HORMONAL CONTROL - glucagon and insulin
Protein Metabolism in the liver
Body can not store AA, so they must be broken down when in excess.
Amino Acid breakdown releases toxic component - Amine group
Liver is responsible for the removal of the amine group (deamination) and its conversion into a harmless product.
Amine group converted to urea by liver, that is excreted within urine.
Liver can synthesize non essential AA from surplus stock (transamination)
Fat Metabolism
Liver is a major site for converting excess fats, and proteins into fatty acids and triglycerides.
LDL and HDL cholesterol
