How is the Liver Structured?

Question 1

How much does the liver weigh of body mass?

Answer 1

5% of body mass-largest internal organ

Question 2

What is the liver able to do?

Answer 2

Can regenerate itself even if its 65% damaged

Question 3

What is the liver divided into?

Answer 3

2 principle lobes-right and left

Question 4

What does each lobe contain?

Answer 4

100,000 lobules (functional units of the liver)

Question 5

What do each lobules have?

Answer 5

Their own blood supply to maximise blood flow through the liver

Question 6

What are the functions of the liver?

Answer 6

Removes toxins and excess amino acids and break them down and release products back into blood

Question 7

What is the shape of each lobule?

Answer 7

Cylindrical structure with 6 sides

Question 8

What features is in each lobule?

Answer 8

-Central Vein which runs down centre
-Sinusoids carry up ventral vein
-Kupffer cells=resident macrophages=breakdown old RBC’s and bacteria
-Hepatocytes line sinusoids-toxins etc enter hepatocytes then produce blood

Question 9

What features in a hepatocyte?

Answer 9

-Large nucleus
-Golgi apparatus-makes lysosomes which contain lysosomes to break down things
-Microvils on the sinusoids side to increase SA so more substances can be absorbed
-Mitochondria-lots for ATP which is needed for 500 reactions
-Lots of SER to make lipids and cholesterol

Question 10

What are other features of hepatocytes?

Answer 10

Cuboid shape and have high metabolic reactions

Question 11

What is the first stage in blood flow around the liver?

Answer 11

O2 blood enters hepatic artery (HA) from aorta, supplying O2 to cells

Question 12

What is the second stage in blood flow around the liver?

Answer 12

Blood flows into the intestinal artery where blood enters to ileum/SI

Question 13

What is the third stage in blood flow around the liver?

Answer 13

Blood which has entered ileum/SI enters the capillary bed where food/alcohol/toxins are absorbed into the blood

Question 14

What is the fourth stage in blood flow around the liver?

Answer 14

Blood flows away from ileum/SI through the intestinal vein and into the Hepatic Portal Vein (HPV) where deoxygenated O2 blood is transferred from Ileum to liver

Question 15

What is the fifth stage in blood flow around the liver?

Answer 15

Blood from HA mixes with blood from HPV so there is increased O2 for hepatocytes

Question 16

Why is it useful that blood from HA and HPV mix for hepatocytes?

Answer 16

Hepatocytes have a high metabolism due to all of the reactions so need a high rate of aerobic respiration (hence lots of oxygen) to provide the ATP for all of the reactions

Question 17

What is the sixth stage in blood flow around the liver?

Answer 17

Blood flows through sinusoids towards the middle/centre of lobules to central vein

Question 18

What is the seventh stage in blood flow around the liver?

Answer 18

Blood from central vein enters the hepatic vein and flows back to heart via vena cava

Question 19

What is the eighth stage in blood flow around the liver?

Answer 19

Bile canaliculi carry bile outwards to ducts which lead to gall bladder

Question 20

What is the order of size of all the veins,arteries and bile ducts?

Answer 20

-HPV (biggest)
-Bile Ducts (often look ‘empty’)
-HA (smallest)

Question 21

What are the differences between Bile Canaliculi and Sinusoids?

Answer 21

Bile Canaliculi:
-not continuous flow
-outwards flow
-bile
Sinusoids
-continuous flow
-inwards flow
-blood

Question 22

What is the role of the hepatic portal vein?

Answer 22

Carries deoxygenated blood from Ileum /SI to liver which is rich in the products of digestion

Question 23

What is the role of the hepatic artery?

Answer 23

Oxygenated blood enters liver from aorta via hepatic artery which supplies the oxygen which is essential for aerobic respiration