The Liver

Question 1

Describe the larger structure of the liver.

Answer 1

Two lobes - right lobe and left lobe.
Where the peritoneum attaches the liver, you have the right triangular ligament (above right lobe), left triangular ligament (above left lobe), Falciform ligament (between right and left lobe) and Ligamentum Teres (just below that at the bottom of the liver).

Question 2

Name the three ducts that connects the pancreas/ gall bladder to the liver. What do they all do?

Answer 2

Right hepatic duct, left hepatic duct, which join to make the common hepatic duct, drains bile produced by the liver.

Question 3

What two organs supply the liver with deoxygenated blood through the portal vein?

Answer 3

Small intestine and large intestine.

Question 4

What organ supplies oxygenated blood to the liver through the hepatic artery?

Answer 4

The aorta - heart.

Question 5

Where does ‘portal’ vein derive from?

Answer 5

'Port' = gate
'Portare' = carry

Question 6

How is the portal circulatory system different to other circulatory systems?

Answer 6

Blood passes through TWO sets of capillaries instead of one.

Question 7

How does to two-capillary hepatic portal system work?

Answer 7

Arterial blood passes through the stomach and intestine where nutrients are absorbed. It then passes through the hepatic portal vein to the liver, where nutrients leave, before returning back to the heart.

Question 8

What system supplies blood to the anterior pituitary?

Answer 8

The hypothalamo-hypophyseal portal system.

Question 9

What substances travel in the portal veins?

Answer 9

Water, water soluble vitamins, electrolytes (K+, Na+, Ca2+), carbohydrates e.g. Glucose, proteins, hormones (mainly from the pancreas), toxins e.g. Ammonia.

Question 10

What two substances DO NOT travel in the portal vein?

Answer 10

Lipids and fat soluble vitamins (A, K, D).

Question 11

How do lipids enter the liver if not through the portal vein?

Answer 11

Lipids are taken into the cells and processed into CHYLOMICRONS. They are the taken up into lymphatic vessels called LACTEALS (can see on small intestine). Chylomicrons then enter the liver through the HEPATIC ARTERY.

Question 12

What complete cycle does the liver undergo that no other organ can?

Answer 12

The KREBS CYCLE (urea cycle).
Convert ammonia to urea.
Other toxins including chemical, bacterial, viruses, tapeworms, roundworms…

Question 13

Name four functions of the liver.

Answer 13

Metabolism
Storage
Detoxification
Bile production

Question 14

What two types of metabolism occur in the liver and how do they work?

Answer 14

Catabolism (release of energy)

Anabolism (storage of energy e.g. Albumin, glycogen)

Question 15

What two processes can the liver take over after the failure of:
A)The bone marrow
B)The spleen

Answer 15

BM - Haematopoiesis - formation of blood complements from stem cells
S - Removal of aged red blood cells

Question 16

What substances can the liver store?

Answer 16

Proteins
Carbohydrates
Fats: glycogen, lipoproteins, triglycerides
Vitamin B12, D, K

Question 17

What is drug efficacy?

Answer 17

The effect a drug has on the body - based on how well the liver breaks it down.

Question 18

What is the enzyme that can breaks down poisons and toxins in the liver?

Answer 18

Cytochrome p450

Question 19

What percentage of blood enters the liver from the portal vein compared to the hepatic artery?

Answer 19

Portal vein 25%

Hepatic artery 75%

Question 20

What three endocrine functions does the liver have and what are some the substances involved?

Answer 20

Produces - angiotensinogen, thrombopoetin, insulin growth factor 1
Modifies to active forms - vitamin D, thyroxine
Breaks down - insulin, glycogen, oestrogen / progesterone

Question 21

What percentage of liver cells do hepatocytes make up?

Answer 21

80%

Question 22

Name some characteristics of hepatocytes.

Answer 22

Regenerates very well

Numerous in: mitochrondria, peroxisomes, free ribosomes, RER, SER, Golgi complexes, glycogen deposits.

Question 23

What is a sinusoid?

Answer 23

A passage for blood used in the liver, spleen and bone marrow instead of capillaries and venues.

Question 24

What components make up a ‘portal triad’?

Answer 24

The hepatic artery, the portal vein and a bile duct.

Question 25

What do the sets of portal triads meet?

Answer 25

In the central vein

Question 26

Where does the central vein drain?

Answer 26

Into the sublobular vein

Question 27

Looking both closely, what is the cell structure in and around the sinusoids?

Answer 27

The sinusoids include red blood cells, kupffer cells and sinusoid lumen.
Either side of the sinusoid is the space of disse, includes some dendritic cells.
Next to the space of disse are the hepatocytes lined with micovilli.

Question 28

What are Kupffer cells?

Answer 28

Specialist macrophages that line the sinusoids, are exposed to gut bacteria, toxins etc.
Recycle old red blood cells.
They make up 80% of the body’s macrophages and real through small holes in the vessels.

Question 29

What happens in liver cirrhosis?

Answer 29

Hepatic stellate cells lose their vitamin A storage capacity, so differentiate into fibroblasts.
These deposit collagen in the perisinusoidal space, surrounding the central vein and constricting it.
This leads to portal hypertension (high BP in hepatic portal system).