How is the Liver Structured? Flashcards
(23 cards)
How much does the liver weigh of body mass?
5% of body mass-largest internal organ
What is the liver able to do?
Can regenerate itself even if its 65% damaged
What is the liver divided into?
2 principle lobes-right and left
What does each lobe contain?
100,000 lobules (functional units of the liver)
What do each lobules have?
Their own blood supply to maximise blood flow through the liver
What are the functions of the liver?
Removes toxins and excess amino acids and break them down and release products back into blood
What is the shape of each lobule?
Cylindrical structure with 6 sides
What features is in each lobule?
-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
What features in a hepatocyte?
-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
What are other features of hepatocytes?
Cuboid shape and have high metabolic reactions
What is the first stage in blood flow around the liver?
O2 blood enters hepatic artery (HA) from aorta, supplying O2 to cells
What is the second stage in blood flow around the liver?
Blood flows into the intestinal artery where blood enters to ileum/SI
What is the third stage in blood flow around the liver?
Blood which has entered ileum/SI enters the capillary bed where food/alcohol/toxins are absorbed into the blood
What is the fourth stage in blood flow around the liver?
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
What is the fifth stage in blood flow around the liver?
Blood from HA mixes with blood from HPV so there is increased O2 for hepatocytes
Why is it useful that blood from HA and HPV mix for hepatocytes?
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
What is the sixth stage in blood flow around the liver?
Blood flows through sinusoids towards the middle/centre of lobules to central vein
What is the seventh stage in blood flow around the liver?
Blood from central vein enters the hepatic vein and flows back to heart via vena cava
What is the eighth stage in blood flow around the liver?
Bile canaliculi carry bile outwards to ducts which lead to gall bladder
What is the order of size of all the veins,arteries and bile ducts?
-HPV (biggest)
-Bile Ducts (often look ‘empty’)
-HA (smallest)
What are the differences between Bile Canaliculi and Sinusoids?
Bile Canaliculi:
-not continuous flow
-outwards flow
-bile
Sinusoids
-continuous flow
-inwards flow
-blood
What is the role of the hepatic portal vein?
Carries deoxygenated blood from Ileum /SI to liver which is rich in the products of digestion
What is the role of the hepatic artery?
Oxygenated blood enters liver from aorta via hepatic artery which supplies the oxygen which is essential for aerobic respiration
