Liver

Question 1

How many litres of bile do we produce per day?

Answer 1

1 litre

Question 2

What is the hepatic portal system?

Answer 2

The hepatic portal system is the system of veins comprising the hepatic portal vein and its tributaries.

Question 3

What is the hypothalamo-hypophyseal portal system?

Answer 3

The hypophyseal portal system is a system of blood vessels in the brain that connects the hypothalamus with the anterior pituitary.

Question 4

How do portal circulatory systems differ from the typical circulatory route?

Answer 4

The blood passes through two sets of smaller vessels before returning to the heart

Question 5

Where does blood from the first set of capillaries in a portal system collect?

Answer 5

In portal vessels (portal veins)

Question 6

What is the function of the hepatic portal system?

Answer 6

It is responsible for directing blood from parts of the gastrointestinal tract to the liver

Question 7

What is travelling in the portal vein?

Answer 7

Water, water soluble vitamins, electrolytes, carbohydrates, proteins, intestinal hormones and toxins, including ammonia

Question 8

Can ammonia cross the blood-brain barrier?

Answer 8

Yes!

Question 9

The liver is the only organ in the body is which what cycle is expressed?

Answer 9

The complete urea cycle - converts ammonia to urea which can then be excreted in the urine

Question 10

What is not travelling in the portal vein?

Answer 10

Lipids and fat soluble vitamins (A, D, E and K) which go into lacteals

Question 11

Lipids are taken into cells and processed into what?

Answer 11

Chylomicrons, which are taken up by lymphatics called lacteals

Question 12

What are lacteals?

Answer 12

Specialised lymphatic vessles that drain into the abdominal lymphatics that then drain into the thoracic duct which joins the venous system at the junction of the left internal jugular vein and subclavian vein.

Question 13

How do chylomicrons enter the liver?

Answer 13

Hepatic artery

Question 14

What are the functions of the liver?

Answer 14

Metabolism, storage, detoxification, bile production

Question 15

What does the liver store?

Answer 15

Glycogen, iron, vitamins A, B12, D and K

Question 16

What does the liver produce?

Answer 16

Bile, albumin, glycogen, numerous coagulation factors, complement components of immune system

Question 17

What does the liver break down?

Answer 17

Drugs (cytochrome P450), hormones, haemoglobin, poisons

Can also take over removal of aged red cells after splenectomy

Question 18

What are cytochrome p450s?

Answer 18

Family of haem containing isoenzymes which ae located in the smooth ER of several tissues, metabolise poisons and drugs

Question 19

What are Kupffer cells?

Answer 19

Specialized macrophages located in the liver, form part of the lining of sinusoids

Question 20

What is a sinusoid?

Answer 20

An irregular tubular space for the passage of blood, taking the place of capillaries and venules in the liver, spleen and bone marow.

Question 21

How are human liver lobules classically described?

Answer 21

Hexagonal

Question 22

What are Stellate (Ito) cells full of?

Answer 22

Cytoplasmic vacuoles cotaining vitamin A

Question 23

In liver cirrhosis, what happens to hepatic stellate cells?

Answer 23

They lose their vitamin A storage capability and differentiate into myofibroblasts which synthesise and deposit collagen within the perisinusoidal space, resulting in liver fibrosis.

Question 24

How is portal hypertension caused in patients with cirrhosis?

Answer 24

Collagen deposited by the myofibroblasts surrounds the central vein, constricting it

Question 25

What makes up the portal triad?

Answer 25

Proper hepatic artery, hepatic portal vein and common bile duct