Liver structure and function

Question 1

Liver anatomy

Answer 1

Greatest organ in the human body- 1.4 kg
Divided into two big lobes: right>left
and two smaller lobes: caudate> quadrate
Covered in connective tissue and visceral peritoneum in all points except the BARE AREA on the diaphagmatic surface

Question 2

What is the PORTA and where is it situated

Answer 2

it is the point of entry of lymphatics/ blood vessels to the liver
it is situated on the inferior surface

Question 3

What happens at the PORTA?

Answer 3

the connective tissue separates out into septa which divide the liver into hexagonal lobules

Question 4

what is found at the corner of the hexagonal lobules?

Answer 4

The portal train:
hepatic portal vein / hepatic artery- carry blood in
hepatic duct- carries bile out

Question 5

what is found at the centre of each lobule? and where does this drain

Answer 5

the central vein- drains into HEPATIC VEINS INTO IVC

Question 6

what are the liver cells called at what do they make up?

Answer 6

liver cells are called hepatocytes

they group up to form hepatic cords

Question 7

what is found between hepatocytes?

Answer 7

hepatic sinusoids

Bile cannuliculi

Question 8

What happens to blood in the liver

Answer 8

• Blood from the hepatic portal vein mixes with blood from the hepatic artery and passes into the hepatic sinusoids
• As blood passes through the hepatic sinusoids it is filtered by the hepatocytes
• once filtered by the hepatocytes it passes into the hepatic vein and from there into the IVC
• Bile produced from the hepatocytes passes into the cannuliculi and from there into the hepatic ducts

Question 9

Describe the differences between blood in the hepatic artery and portal vein

Answer 9

hepatic portal vein: 02 poor- nutrient rich

hepatic artery: 02 rich, nutrient poor

Question 10

What the functions of the hepatocytes?

Answer 10

-Storage: 
Glycogen 
Iron 
Copper 
-Synthesis:
Glucose, glycogen 
Bile 
-Detoxification :
Breaks down NH3 into urea
Breaks down insulin and glucagon 
-Immunological functions

Question 11

What is bile made of?

Answer 11

• cholesterol
• bile acids
• bile pigments
• bicarbonate ions
• lecithin
• toxic metals

Question 12

which components of bile are synthesised in the liver? and what do they do?

Answer 12

cholesterol
bile acids
lecithin
they break down fat

Question 13

which components of bile and secreted by hepatocytes

Answer 13

bile acids
cholesterol 
lecithin 
bile pigments
toxic metals

Question 14

where is bicarbonate in bile secreted from?

Answer 14

duct cells of the pancreas

Question 15

What is bilirubin

Answer 15

Main bile pigment- extracted from old/damaged erythrocytes

Question 16

Why is bile yellow?

Answer 16

bilirubin extracted from old blood and secreted into bile by hepatocytes

Question 17

why are faeces brown?

Answer 17

in the large intestine- bacterial enzymes modify bilirubin

Question 18

why is urine yellow?

Answer 18

Bilirubin is not broken down by bacterial enzymes- becomes reabsorbed and as it is yellow it turns urine yellow

Question 19

What are bile salts?

Answer 19

They are produced by the liver daily from cholesterol
They are mixed with Taurine/Glycine to increase solubility
Used to break down fat

Question 20

How are bile salts recycled?

Answer 20

Enteropathic circulation

Liver- common bile duct-Duodenum- common hepatic vein- liver

Question 21

Layers of the gall bladder

Answer 21

• mucose
• muscularis- smooth
• serosa

Question 22

how is secretion of bile controlled in the gall bladder?

Answer 22

Sphincter of Oddi.
When it relaxes (e.g. in the presence of Fat)- bile and pancreatic juice released into the duodenum
When it contracts- bile is concentrated