Liver Flashcards
What does hepatic mean
Something related to the liver
What does ferrous mean
Something related to iron
What are the main functions of the liver
Maintain blood glucose levels
Produces ketone bodies, amino acids and other nutrients
Distributes cholestrols and triglycerides
Manufacturing plasma proteins (albumin) and most coagulation factors (blood clotting)
Acid-base balance (H+, bicarbonate)
Removes waste products (bilirubin, several drugs such as alcohol and caffeine)
Inactivates some neurotransmitters and hormones
Involved in iron balance and copper metabolism
Filters/inactivates bacteria and viruses from the gut
Makes bile (digestion and waste) and synthesises bile saltsWhere is the liver located
Where is the liver located
Located under the ribcage, mainly on the right hand side of the body
Is the liver assymetrical or symmetrical
asymetrical
Describe the parts which provide blood to the liver and also the parts which bring blood away from the liver
The hepatic vein
Hepatic arteries
Hepatic portal vein
What does the hepatic artery do? What sorts of nutrients and oxygen levels are there
Responsible for delivering oxygenated blood to the liver from the heart. It contains oxygen rich blood, and provides small amount of nutrients to liver, including glucose and amino acids
(O2 rich blood)
What does the hepatic vein do? What sorts of nutrients and oxygen levels are there
Responsible for taking deoxygenated blood from the liver and return it to the inferior vena cava (back to heart)
It carries blood with low O2 levels as the liver uses oxygen from blood during metabolic processes
Carries blood with low nutrients as it has just gone through the liver which extracts nutrients
(O2 poor blood)
What does the hepatic portal vein do? What sorts of nutrients and oxygen levels are there
Carries blood from the gastrointestinal tract to the liver
Carries blood with low O2 levels as the gut just used it for digestion
Carries nutrients absorbed from the guts. Thus, variable nutrients depending on whether someone has just eaten
Nutrient rich blood(?)
What are the main cells of the liver called
Hepatocytes. These are responsible for most of the functions in the liver
What are liver lobules
They are a collection of hepatocytes. They have various vessels bringing blood into the liver and out.
What do portal triads do
It has the hepatic artery, hepatic portal vein and the bile duct (hepatic duct) through it. This allows for transport of blood into the liver lobules and oxygenates it and provides nutrients for it, whilst carrying bile away from the liver lobules
What does the hepatic duct do
Collects bile from the liver and transports it away from the liver
What does the central vein do
It drains blood away from the liver lobule
What is cholesterol
A waxy, fat-like substance made in the liver, and found in the blood and in all cells of the body. Cholesterol is important for good health and is needed for making cell walls, tissues, hormones, vitamin D, and bile acid.
Why is cholesterol important
important for cell membranes and as a building block for many major hormones. However, we don’t want too much because if not it builds up in the blood vessels and can causes blockages –> bad.
What are the two types of cholesterol)
high density lipoprotein (good cholesterol)
low density lipoprotein (bad cholesterol)
What does low density lipoprotein (LDL) do?
It carries cholesterol away from liver to deposit into peripheral vessels. This is needed to build the structure of cell membranes and makes hormones
What does high density lipoprotein(HDL) do?
Carries cholesterol away from peripheral vessels.
This excess cholesterol is then removed via bile
What is albumin
It is a blood protein responsible for maintaining blood osmolarity (water moving from low solute conc to high solute conc) to dilute blood and maintain water in blood
It does this by increasing osmolarity within the blood, preventing water loss into interstitial fluid (which has a higher solute concentration)
What does high osmolarity mean
High solute concentration, opposite for low osmolarity
What is important in helping red blood cells to carry oxygen
Iron
Is free iron harmless or harmful
Free iron is toxic
How can iron be stored in a non toxic form
Through transferrin; a glycoprotein which carries 2 atoms of iron at once
What can increase amount of iron in circulation
absorption from gut (diet)
recycling of old blood cells
Release from storage in liver (stored in ferritin)
What can decrease amount of iron in circulation
Making red blood cells
Blood loss(injury, menstruation)
cell lost from skin and lining of gut
Do we have a mechanism to get rid of excess iron
No
How can iron get into the liver
Through transferrin binding to a receptor on the cell surface (transferrin receptor), which allows for it to move inside the liver cells and release its iron
How can iron exit the liver
Can only exit through a transmembrane iron transporter called ferroportin
What does hepcidin do
Hepcidin is secreted primarily by hepatocytes into the circulation, where it functions to inhibit iron absorption in the proximal small intestine and iron release from RE macrophages by binding to ferroportin and making it degrade.
What does ferroportin do
Ferroportin is a transmembrane protein that transports iron from the inside of a cell to the outside of the cell. Ferroportin is the only known iron exporter.
So how are iron levels controlled by the liver
Through a negative feedback loop
Controller of this is the hormone hepcidin which is manufactured by the liver.
Ferroportin acts like a tap, releasing iron into bloodstream. Hepcidin ‘turns the tap off’, as it binds to ferroportin, removing it from the membrane and breaking it down, preventing release of iron from cells into the bloodstream-
When cells of liver detect iron content in bloodstream is too high, release of hepcidin increases –> acts on cells to prevent their release of stored iron. However, if it is too low, hepcidin decreases, allowing iron to escape
What are normal levels of transferrin?
~250-300 mg/deciliter
