Liver Physiology

Question 1

Metabolic functions of Liver

Answer 1

1. Storage site for Vitamins esp VitA, Vit B12, D (prevents deficiency for 3-4 months)
2. Stores iron as ferritin until needed -blood- iron buffer )(apoferritin)
3. Form coagulation fx
4. removes/ excretes drugs
5. Immunoglobulin function- Kuppfer cells- act as sive for Bacteria & antigens.

Buffer for carbs
Provision of ketones when starvation
Emergency glucose generation
Liver: free fatty acids –> beta oxidation-> ketones–> acetates.

Question 2

What coagulation Fx does the liver make?

Answer 2

Fibrinogen
Prothrombin
Accelerator globulin
Factor VII 
Vit K

Question 3

What factors is ViT K needed for?

Answer 3

1972

2,7,9,10.

Question 4

What drugs does the liver excrete?/ hormones

Answer 4

Excretes/ detoxifies into bile many drugs
Sulfunimides, penicillin, ampicillin, erythromycin.
Endocrine Hormones/ chemically altered or excreted esp thyroxine.
Steroid hormones: oestrogen, aldosterone, cortisol.
Liver failure–> Xs hormones in body fluids, so over activity of liver to compensate.m

Question 5

Biritubin in bile:

Answer 5

Used as a diagnostic tool for haemolytic diseases + some liver diseases.

Question 6

How many days do RBCs survive?

Answer 6

120days

Question 7

What happens to fragile RBCs Hb?

Answer 7

Fragil membranous rupture–> released HB is phagocytosed by teticuloendothelial cells

Question 8

What does Hb separate into?

Answer 8

Globin & Heme

Question 9

What happens to heme?

Answer 9

1. Free iron- transported to blood by transferrin

2. 4 purrole nuclei (bilirubin substrate)

Question 10

What happens to the biribun substrate?

Answer 10

Becomes biliverdin by Heme oxygenase then unconjuvated bilirubin which is released by macrophages into plasma
Goes to Liver
Then it combines w/ albumin and they are transported to blood together.

Question 11

Is glycogen stored in acute liver failure?

Answer 11

Cannot be stored in liver.
Remember, there is no glucgenolysis from muscles to blood glucose.

Alcohol + atherosclerosis reversible.
Alcohol = not atherosclerosis.

Question 12

What happens in atherosclerosis in alcoholics?

Answer 12

NOT normal circulating glucose
1. Hypoglycaemic mostly.
Shaking hands,

Question 13

What happens when the liver stops working?

Answer 13

1. No ketones.. Given.

2. No cholesterol : synthesis: 80-90% in Liver

Question 14

Lack of atherosclerosis in alcoholics

Answer 14

FFA–> atherosclerosis
Long hypoglycaemic periods, FFAs low in circulation, relseased from adipocytes.
No ketone production, no cholesterol synthesis, FFAs are used as the only energy source.
Tissues normally prefer ketones + glucose
Might even absorb cholesterol from palques.

Question 15

Amino acid metabolism

Answer 15

AAs– body bot very economical
Cant reuse AA that u absorb from food
Split them into N and carbon backbones
Then re-synthesise them by adding the N tomthe carbon backbone

Question 16

Synthetic avtivity of hepatocytes

Answer 16

Plasma proteins- everything except immunoglobulins.
Clotting factors
Acute phase protein - immunological protein production
⭐️ more susceptible to infxs
⭐️⭐️⭐️ albumin: protein of world.

Question 17

LPS (lipopolysaccharide)

Answer 17

Bacterial lipopolysacharides, the outermost layer of gram _ve bacteria
It binds to pattern recognition receptors in APCs (macrophage + dendritic cells) and causes activation (massive amounts of cytokines -enough to kill u)
Gut full of gram -ve Bacteria. Some die. When dead they release LPS…
⭐️ crucial function of bile salts is to neutralise LPS.
+ not absob ot.
So… U r more susceptible to immunological diseases.

Question 18

Detoxifying/ excretory role

Answer 18

Kideny–> gets rid of wate soluble toxins/ pharma cpds.
Liver: turns lipid soluble molecules to water soluble (microsomal oxidation, conjugation to suphate)
–> makes them excretable and somts biologically inactive.
Som the excreted into bile.
Some drugs tho rely on liver for chemical modification.

Question 19

Acute liver disease

Answer 19

ALF rare
Commonest -70-80% drug related
Commonest- paracetamol overdosing
20-30% remaining:
Fulminant viral hepatitis
Poisoning( mushrooms, recreational drugs, pesticides)
Liver blood flow prbs- shock, sepsis, Budd-Chiary = hepatic vein thrombosis (compensated)
Blood cannot leave liver, adipocytes hypoxia.
ALF⬆️⬆️ unconjugated bilirubin.
Idiopac

Question 20

What are stellate cells in the liver?

Answer 20

Perisinusoidal cells in the space of Disse, involved in liver fibrosis, producing scar tissue, involved in liver damage.