LIVER FUNCTION

Gross Anatomy/ Macroscopic Appearance

Weighs: 1.2 – 1.5 kg
© you just have to imagine that your liver is about the size of a football, although this can increase to over 10
kg especially in chronic cirrhosis
Located at the right-hand part of the abdomen, behind the lower ribs
© The ribs are also a means of protecting the liver and other internal organs such as the heart.
Divided into 2 lobes by falciform ligament
A. Right lobe (Red) – 6x larger than left lobe
B. Left lobe (blue)
» However, there is no known functional difference between the lobes and the communications flows freely between all
areas of the liver.

Front view of the liver:

© Our liver is functionally divided into 2 lobes: right and left.
© The external division is marked on the front of the liver by a falciform ligament
» Falciform ligament attaches the liver to the front body wall; separates the liver into the left
medial lobe and the right lateral lobe.

Back view of the liver:

© The right lobe is separated from the other lobes by the gallbladder fossa (green part) and
the fossa for the inferior vena cava.
- When we say fossa, it means it’s a shallow depression, pit, shallow part or a hollow part of
an organ.
© Left lobe includes the quadrate lobe and the caudate lobe.

Functions of The Liver

1. Metabolism (Catabolism/anabolism) – Capable of metabolizing proteins, carbohydrates, and fats
2. Storage
§ Stores carbohydrate (CHO) such as: glycogen, lipoproteins.
» Lipoproteins are types of proteins that carry lipids; common cause of confusion
§ Fats and triglycerides (TAG)
3. Synthesis
§ Main substances produced by the liver are proteins like albumin and also blood clotting factors
TAKE NOTE: Your liver is the one producing bile – because your bile is stored in the gallbladder.
» Bile is a digestive fluid which is produced from the liver but it is stored in the gallbladder.
4. Detoxification
§ The liver plays several roles in detoxification:
(a) Filters our blood to remove large toxins
(b) Bile synthesized by the liver is full of cholesterol and other fat-soluble toxins; in short, the liver removes toxins from our
body through this bile
(c) It will disassemble unwanted chemicals so that it could be removed out from our body
(d) Cytochrome P450 – enzyme that is involved in the detoxification process of the liver and it decreases drug efficacy.
TAKE NOTE: The drugs that we take are foreign to our body.
What will happen now?
The liver will breakdown the drug so it won’t hurt our body and specific dose will be given to account for the amount to be
detoxified
5. Bile production

Blood Supply to the Liver

About approximately 1500 mL/min blood passes the liver; detoxified and is used up in the liver

Blood enter via:

Hepatic artery Portal vein
Ø blood from the heart will enter the liver via hepatic artery Ø blood is supplied to the liver through this portal vein
» This supplies blood to the liver from the heart that’s why it is » The portal vein will carry the blood to the liver and that
oxygen-rich comes from our gastrointestinal tract (GI tract) that’s why it
» This accounts for the 25% of the total blood supply is nutrient rich.
» This accounts for 75% of the total blood supply.

Blood leaves via:

Hepatic vein Hepatic ducts
We can assume that because the blood has been used up by the liver so it It could leave the hepatic ducts that may carry the bile towards
is already nutrient and oxygen depleted. gallbladder

Image with the artery, veins, and ducts

The portal circulation
In this illustration we can see that the venous blood coming from gastrointestinal tract
drains into the superior and inferior mesenteric vein. These 2 vessels are then joined
by the splenic vein just posterior to the neck of the pancreas. These 3 will form a portal
vein and then it will split to form the right and the left branches each supplying about
half the liver with blood coming from the GI Tract. The portal venous blood contains
all the products of digestion absorbed from the GI tract so all useful and non useful
products are processed in the liver before being either released back into the hepatic
veins which join the inferior vena cava or stored in the liver for later use

Portal Triad
- Constitutes mainly of the portal vein

Portal vein Hepatic artery Common bile duct

Supplies the blood to the Supplies the liver with blood The bile is excreted out from
liver and that is coming from coming from the heart your liver
our gastrointestinal tract

Billiary Tree
§ Serves as the excretory system of the liver
§ Mainly excretes Bile
§ As mentioned earlier, the bile is produced from the liver and it is stored in the gallbladder (bile sac)
§ Main function of bile: digestion of food that we eat and mainly it emulsifies the fats
o In short, it will breakdown fats into fatty acids which can then be taken into the body by the digestive tract. Again, it aids
in the digestion process

§ Bile contains cholesterol bile pigments, bile acids and also bile salts. Once bile is synthesized in the liver it will pass through the
hepatic duct towards the common hepatic duct and it will go to the cystic duct and now the bile will be stored in the gallbladder
and once the bile is needed for the digestion of food, the gallbladder will squeeze out the bile
§ We have the hormone cholecystokinin (CKK). This hormone coming from the Greek world “chole” means bile, “cysto” means
sac or the bile sac and “kinin” means move or to move. In short , it will help the gallbladder to move or to contract to squeeze
out the bile. That is also the reason why we have this term “cholecystectomy” this means the removal of the gallbladder
§ The hormone cholecystokinin will help the gallbladder contract to squeeze out the bile if needed to digest the food and
cholecystectomy is the removal of the gallbladder
§ Once the bile is excreted from the gallbladder, it will now pass through the common bile duct. This is the last part of the biliary
tract and it reaches the gastrointestinal tract and released into the duodenum so or the first part of the intestine where the bile is
secreted
§ The bile salt now again will emulsify the fats in the ileum and this is the part where the absorption of fats and bile salts occur in the
ileum
§ The bile salts are reabsorbed back to the liver to be used

Microscopic Anatomy of the Liver

Lobules
§ Functional units of the liver
§ Microscopic
§ 6 sided structure with a central vein
§ Each corner contains the portal triads (portal vein, hepatic artery, bile duct)

Major cell types of the liver

Hepatocytes (80%) Kupffer cells
§ Responsible for the regenerate properties of the liver § Specialized macrophages (phagocytes) that line the sinusoids of
§ Remember: your liver can regenerate and for example in the liver
the cases of liver injury or liver damage, all the cells in § Main function: to engulf bacteria and other microorganisms or
the liver can change and divide until the normal size of foreign debris, toxins and other substances flowing thorugh the
the liver is restored. However, if the injury to the liver is sinusoids. In short, they are mainly responsible for eliminating
so serious that the liver could no longer regenerate then a any microorganisms or toxins and substances that could harm
person might need a liver transplant in that case our liver
§ Liver degenertion is mainly the responsibility of § They are a means of protection
hepatocytes § This picture shows us a kupffer cell
traveling through the sinusoid of the
liver