The Liver

Question 1

What are the 6 roles of the liver

Answer 1

1) blood glucose regulation
2) bile drainage
3) blood circulation and filtration
4) detoxification (drugs, alcohol and hydrogen peroxide)
5) synthesis and storage of amino acids acids, proteins, vitamins and fats
6) control lipid levels

Question 2

What is the liver linked to

Answer 2

1) the intestine
2) gall bladder

Question 3

Why does the liver need to be linked to the intestine

Answer 3

So waste products can be taken to the liver for detoxification

Question 4

Why does the liver need to be linked to the gall bladder

Answer 4

To take the bile out of the liver

Question 5

Which storage molecules is required for glucose storage

Answer 5

Glycogen

Question 6

What are the 4 vessels within the liver

Answer 6

1)hepatic vein (central vein)
2) hepatic artery
3) hepatic portal vein
4) bile duct

Question 7

What if the function of the hepatic artery

Answer 7

-brings oxygenated blood into the liver from the aorta
-aerobic respiration

Question 8

What is the function of the hepatic portal vein

Answer 8

-brings deoxygenated blood from the digestive system
-has products of digestion and toxic substances and concentrations get adjusted

Question 9

What are the functions of the hepatic vein

Answer 9

-where blood leaves the liver
-rejoins vena cava for normal circulation

Question 10

What is the function of the bile duct

Answer 10

-bile secreted and carried to gall bladder to be stored until needed for emulsification of fats in the small intestine
-contains excretory products released in faces

Question 11

What are lobes

Answer 11

The sectioning of the liver into left and right lobe

Question 12

What are lobules

Answer 12

-small cylindrical sections within each of the lobes
-they have their own blood supply and are structures to maximise the number of cells in contact with this blood

Question 13

What are cells in the liver called

Answer 13

Hepatocytes

Question 14

What is a feature of hepatocytes

Answer 14

A dense cytoplasm

Question 15

What are the 8 parts of the liver

Answer 15

1) Hepatic vein
2) Sinusoid
3) Bile Canaliculus
4) Bile duct
5) Hepatic portal vein
6) Hepatic artery
7) Hepatocytes (liver cell)
8) Kupffer cell

Question 16

What part of the liver is an intra-lobular vessel

Answer 16

Hepatic vein

Question 17

What parts of the liver are inter-lobular vessels

Answer 17

1) Bile duct
2) Hepatic portal vein
3) Hepatic artery

Question 18

What are sinusoids

Answer 18

Channels that carry blood between rows of cells where blood from the hepatic vein and hepatic artery mixes

Question 19

What are the kupffer cells

Answer 19

Macrophages that break down old red blood cells and release bilirubin

Question 20

What function do bile canaliculus have

Answer 20

Carries bile which the hepatocytes secretes and drains into the bile ductules

Question 21

What is the average mass of protein an adult needs per day

Answer 21

40-60g

Question 22

What is the problem with consuming too much protein

Answer 22

Too much protein means that your body cannot store the amino acids (in the protein) because of the toxicity of their amine group

Question 23

How does the liver solve the problem of not being able to store amino acids

Answer 23

By converting the amino-acids to urea to be excreted in a two step process

Question 24

What is the overall equation of the conversion of amino acids

Answer 24

Amino acids ——> Ammonia ——> Urea
^ ^
| |
Deamination Urea formation

Question 25

Explain the first step of the conversion of amino-acids

Answer 25

1) Deamination Amino acid + oxygen ——> Keto-acid + Ammonia ^ | Enters respiration

Question 26

Why are amino acids not directly excreted

Answer 26

-as they contain a large amount of energy

Question 27

Why is ammonia still converted and what is it converted to

Answer 27

-as it is still highly soluble and very toxic -is converted to urea which is less toxic

Question 28

What is the cycle that ammonia is converted in called

Answer 28

The Ornithine cycle

Question 29

Describe the second step of the two step process in the conversion of amino acid

Answer 29

urea formation: 1) CO2 + NH3 is added to ornithine which produces H2O and citrulline 2) NH3 is added to citrulline which produces H2O and arginine 3) H2O is added to arginine which produces urea 4) this urea goes to the kidney to be excreted

Question 30

What substances does the liver detoxify

Answer 30

1) drugs consumed 2) hydrogen peroxide (which is produced in cells) 3) alcohol

Question 31

How does the liver detoxify drugs

Answer 31

-A group of enzymes Cytochrome P450 break down drugs such as cocaine as well as medical drugs

Question 32

How does the liver detoxify Hydrogen peroxide (produced in cells)

Answer 32

-catalase (enzyme) converts hydrogen peroxide to water and oxygen to prevent the build up of toxic molecules in cells

Question 33

Why does the liver have to detoxify alcohol

Answer 33

-as it contains ethanol ( a drug) that suppresses nerve activity

Question 34

When detoxified how can ethanol be used

Answer 34

-To produce energy for respiration

Question 35

Explain how alcohol is detoxified

Answer 35

REDOX reaction: Ethanol= oxidised NAD= reduced 1) ethanol is oxidised to form ethanal, using the enzyme ethanol dehydrogenase and NAD is reduced in the process (using the H+ ion form ethanol) 2) ethanal is oxidised to form ethanoic acid (ethanoate) (acetate), using the enzymes ethanal dehydrogenase and NAD is reduced in the process (using the H+ ion from the ethanal )

Question 36

What is the detoxification of alcohol called

Answer 36

Redox reaction -ethanol is oxidised -NAD is reduced

Question 37

What is NAD also needed for

Answer 37

To oxidise and break down fatty acids to use in respiration

Question 38

What is the problem with drinking too much alcohol and what could it cause

Answer 38

-the liver has to detoxify too much alcohol so it uses all its stored NAD so there is not enough NAD left to break down the fatty acids - the fatty acids will then be converted back to lipids and gets stored in the hepatocytes causing an enlarged fatty liver and possible hepatitis/cirrhosis

Question 39

What does intra-lobular mean

Answer 39

Within a lobule

Question 40

What does inter-lobular mean

Answer 40

Between lobules

Question 41

In what organelle does the ornithine cycle take place in

Answer 41

Mitochondria