Liver

Question 1

What does hepatic mean

Answer 1

Something related to the liver

Question 2

What does ferrous mean

Answer 2

Something related to iron

Question 3

What are the main functions of the liver

Answer 3

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

Question 4

Where is the liver located

Answer 4

Located under the ribcage, mainly on the right hand side of the body

Question 4

Is the liver assymetrical or symmetrical

Answer 4

asymetrical

Question 5

Describe the parts which provide blood to the liver and also the parts which bring blood away from the liver

Answer 5

The hepatic vein

Hepatic arteries

Hepatic portal vein

Question 6

What does the hepatic artery do? What sorts of nutrients and oxygen levels are there

Answer 6

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)

Question 7

What does the hepatic vein do? What sorts of nutrients and oxygen levels are there

Answer 7

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)

Question 8

What does the hepatic portal vein do? What sorts of nutrients and oxygen levels are there

Answer 8

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(?)

Question 9

What are the main cells of the liver called

Answer 9

Hepatocytes. These are responsible for most of the functions in the liver

Question 10

What are liver lobules

Answer 10

They are a collection of hepatocytes. They have various vessels bringing blood into the liver and out.

Question 11

What do portal triads do

Answer 11

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

Question 12

What does the hepatic duct do

Answer 12

Collects bile from the liver and transports it away from the liver

Question 13

What does the central vein do

Answer 13

It drains blood away from the liver lobule

Question 14

What is cholesterol

Answer 14

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.

Question 15

Why is cholesterol important

Answer 15

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.

Question 16

What are the two types of cholesterol)

Answer 16

high density lipoprotein (good cholesterol)

low density lipoprotein (bad cholesterol)

Question 17

What does low density lipoprotein (LDL) do?

Answer 17

It carries cholesterol away from liver to deposit into peripheral vessels. This is needed to build the structure of cell membranes and makes hormones

Question 18

What does high density lipoprotein(HDL) do?

Answer 18

Carries cholesterol away from peripheral vessels.

This excess cholesterol is then removed via bile

Question 19

What is albumin

Answer 19

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)

Question 20

What does high osmolarity mean

Answer 20

High solute concentration, opposite for low osmolarity

Question 21

What is important in helping red blood cells to carry oxygen

Answer 21

Iron

Question 22

Is free iron harmless or harmful

Answer 22

Free iron is toxic

Question 23

How can iron be stored in a non toxic form

Answer 23

Through transferrin; a glycoprotein which carries 2 atoms of iron at once

Question 24

What can increase amount of iron in circulation

Answer 24

absorption from gut (diet)

recycling of old blood cells

Release from storage in liver (stored in ferritin)

Question 25

What can decrease amount of iron in circulation

Answer 25

Making red blood cells

Blood loss(injury, menstruation)

cell lost from skin and lining of gut

Question 26

Do we have a mechanism to get rid of excess iron

Answer 26

No

Question 27

How can iron get into the liver

Answer 27

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

Question 28

How can iron exit the liver

Answer 28

Can only exit through a transmembrane iron transporter called ferroportin

Question 29

What does hepcidin do

Answer 29

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.

Question 30

What does ferroportin do

Answer 30

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.

Question 31

So how are iron levels controlled by the liver

Answer 31

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

Question 32

What are normal levels of transferrin?

Answer 32

~250-300 mg/deciliter