Liver as a storage organ

Question 1

What are the functions of the liver?

Answer 1

Metabolism of fat, protein, carbohydrate, hormones
Toxin/drug metabolism and excretion
storage
bilirubin metabolism and excretion

Question 2

Where is iron absorbed?
Where in the body is iron used?

Answer 2

duodenum

bone marrow - used to make red blood cells
muscles - used to make myoglobin
stored in the liver

Question 3

How is iron lost from the body?

Answer 3

sloughed mucosal cells
desquamation
menstruation
blood loss

very little is lost overall

Question 4

What is ferritin?

Answer 4

large spherical protein found in cytoplasm of cells, can be in serum.
subunits form a shell surrounding a central core
core contains up to 5000 atoms of iron

Question 5

How does the body store iron?

Answer 5

ferritin protein

Question 6

What causes ferritin to rise in the blood?

Answer 6

Excess iron storage disorders - iron overload
or
non-iron overload - unrealated things that cause a rise in the blood
e.g. liver disease or acute phase response

Question 7

What causes ferritin deficiency? What shows it?

Answer 7

Iron deficiency - only significant known cause
Low concentration in the blood

Question 8

What do vitamins act as?

Answer 8

gene activators
- free-radical scavengers
- coenzymes or cofactors in metabolic reactions

Question 10

Difference between fat and water soluble vitamins?

Answer 10

Water soluble pass more readily through the body so require more regular intake than fat soluble

Question 11

Vitamin A

Answer 11

Fat soluble
Retinoids
Meat and dairy products -
Converted from carotenes - carrots, sweet potatoes, tomatoes, spinach

Question 12

Requirements for Vitamin A?

Answer 12

0.6 mg/day men
0.7 women

Question 13

Functions of Vitamin A?

Answer 13

Vision
- forms rhodopsin in rod cells
Reproduction
-spermatogenesis
- prevent reabsorption of fetus
Growth
Stabilisation of cellular membranes

Question 14

Vitamin A deficiency?
Vitamin A excess?

Answer 14

Rare in more developed countries
May occur due to fat

ELEPHANT

Question 15

Vitamin D functions?

Answer 15

Increase intestinal absorption of calcium
Reabsorption and formation of bone
Reduced renal excretion of calcium

Question 16

What happens in a vitamin D deficiency?

Answer 16

demineralisation of bone
- rickets in children
- osteomalacia in adults

Question 17

WHerre is vitamin D found?

Answer 17

sunlight and fish/meat or supplements
stored in liver, when needed goes to the kidneys
Converted to form that performs these functions

Question 18

Where is vitamin E stored?

Answer 18

Fat soluble
Adipose cells - fixed pool
Non-adopose cells - liver and plasma - labile and fixed pool

Question 19

Where is vitamin E absorbed from?

Answer 19

almonds
avocadoes
spinach
carrots
oils
etc

Question 20

Role of vitamin E?

Answer 20

important antioxidant

4mg/day men
3 women

Question 21

Vitamin E deficiency
caused by?
clinical manifestation?

Vitamin E excess?

Answer 21

• fat malabsorption, premature infants, rare congenital defects
• haemolytic anaemia, myopathy, retinopathy, ataxia, neuropathy
• relatively safe in excess

Question 22

Where Vitamin K stored?

Answer 22

rapid take up by the liver
transferred to very low density lipoproteins
and low density lipoproteins that carry it to the plasma

Question 23

Sources of Vitamin K

Question 24

Functions of Vitamin K?

Answer 24

Activation of blood clotting factors
necessary for liver synthesis of plasma clotting factors II, VII, IX and X
Can be…

Question 25

Deficiency and excess of Vitamin K?

Question 26

What are the fat soluble vitamins?

Answer 26

A, E, D, K

Question 27

Where is vitmin C found?
Requirements per day?

Answer 27

Fresh fruit and veg

40 mg/day

Question 28

Functions of vitamin C?

Answer 28

collagen synthesis
antioxidant
iron absorption

Question 29

Vitamin C deficiency?

Answer 29

Scurvy
-easy bruising and bleeding
- teeth and gum disease
- hair loss

treatment with vitamin C improves symptoms quickly

Question 30

Vitamin C excess?

Answer 30

doses >1g/day - GI side effects
no evidence it helps colds

Question 31

Is vitamin C water or fat soluble?

Answer 31

water soluble

Question 32

What are the 2 active forms of VB12?

Answer 32

methylcobalamin
5-deoxyadenosylcobalamin

Question 33

Absorption of vitamin B12?

Answer 33

released from food
binds to R protein to protect it from stomach acid
released from proteins by pancreatic polypeptide
Intrinsic factor needed for absorption
IF-B12 complex absorbed in terminal ileum
stored in liver

Question 34

What contains vitamin B12?

Answer 34

meat
fish
eggs
dairy

Question 35

Vitamin b12 excess and deficiency

Question 36

-

Answer 36

-

Question 37

Folate

Answer 37

Foods with folic acid
higher requirement in pregnancy

is a coenzyme in methylation reaction
DNA synthesis
synthesis of methionine and homocysteine

Answer 38

s

Question 39

How are the two clotting factor pathways activated?

Answer 39

intrinsic pathway - contact

extrinsic pathway - FVII coming into contact with tissue factor

initiate cascade results in fibrin clot formation

Question 40

Which clotting factors are produced in the liver?

Answer 40

I fibrinogen, II prothrombin, IV, V, VI, VII

Question 41

How can the performance of clotting pathways be measured?

Answer 41

prothrombin time/PT (extrinsic pathway)
international normalised ratio/INR
activated partial thromboplastin time/aPPT (intrinsic pathway)

Question 42

What might a prolonged PT indicate in the liver? What can cause it outside of the liver?

Answer 42

In liver - deficiency in the synthetic capacity of the liver
Other - DIC, severe GI bleeding, some drugs, Vitamin K deficiency

Question 43

What are the water soluble vitamins?

Answer 43

Folate
Vitamin C
Vitamin B12