GI Liver storage

Question 1

Which vitamins are fat soluble?

Answer 1

A, D, E, and K. Allows them to be more eaisly stored in the body.

Question 2

What regulates free Fe3+ in the body?

Answer 2

Transferrins in plasma.

Question 3

Where is dietary iron used?

Answer 3

For myoglobin in muscles, bone marrow for hemoglobin production, the liver.

Question 4

Where is dietary iron stored?

Answer 4

The liver parenchyma.

Question 5

What is the process for the breakdown of erythrocytes?

Answer 5

Reticulo-endothelial macrophages break down haemoglobin to produce free Fe3+.

Question 6

What are the types of dietary iron?

Answer 6

Heme associated and free Fe3+.

Question 7

How is heme associated iron absorbed?

Answer 7

It enters the cell through a heme transporter and can then

Question 8

How is heme associated iron absorbed?

Answer 8

It enters the cell through a heme transporter and can then either directly exist the cell as Fe2+ or become combined with ferratin and then exit the cell.

Question 9

What is the role of Cytochrome B in the absorption of dietary iron?

Answer 9

Duodenal cytochrome B converts Fe3+ to Fe2+ so that it can be transported into the cell. Cytochrome B on the basolatteral membrane converts Fe2+ back to Fe3+ to be absorbed into the portal blood.

Question 10

What is the transporter for free iron Fe2+ into the cell?

Answer 10

DMT1. Divalent metal transporter 1.

Question 11

What is the transporter for iron out of the cell?

Answer 11

Ferroportin 1.

Question 12

How is dietary B12 protected against gastric juice?

Answer 12

It is bound to R protien.

Question 13

Where is R protein made?

Answer 13

The salivary glands and the stomach.

Question 14

When is R protein removed from B12 and by what?

Answer 14

Pancreatic enzymes remove the R group in the duodenum/ jejunum.

Question 15

What allows B12 to be absorbed?

Answer 15

Intrinsic factor.

Question 16

Where is intrinsic factor produced?

Answer 16

The parietal cells of the stomach.

Question 17

Where is B12 absorbed?

Answer 17

In the ileum as it can bind to intrinsic factor receptors.

Question 18

How is B12 metabolised?

Answer 18

In the liver B12 is part of the cycle which allows the production of folate for nucleic acid synthesis and methyonine for reactions.

Question 19

How and where is vitamin A metabolised?

Answer 19

In the intestines the retinols and carationids are converted to retinol esters. These are then transported in chylomicrons to the hepatocytes of the liver. In the liver they are stored as retinyl esters.

Question 20

How and where is vitamin D metabolised?

Answer 20

Cholecaliciferol is metabolised in the liver to form inactive hydroy-vitamin D3 which is then activated in the kidneys to dihydroxy- vitamin D3.

Question 21

Which protiens are produced by the liver?

Answer 21

Plasma protiens e.g. albumin, Hemostatis factors (clot formation), Fibrinolysis factors (breakdown clots), carrier protiens, Hormones e.g. growth factor 1, Prohormones e.g. angiotensin.

Question 22

What happens to excess amino acids?

Answer 22

They are metabolised and there skeleton used in alpha keto acids.

Question 23

What is alpha keto acids importance?

Answer 23

It is an important electron exchanger in the krebs cycle.

Question 24

What stimulates glutamate+h2O conversion to alpha keto glutarate?

Answer 24

Decreased energy= increased ADP= increased alpha keto glutarate. More alpha keto acid so more krebs so more energy.

Question 25

What occurs to amino acids if there is high energy?

Answer 25

They remain as glutamate which can be incorporated into proteins.

Question 26

What are the functions of albumin?

Answer 26

Bind and transport NSAIDS.
Maintain colloid osmotic pressure
Act as a free radical scavenger
Anti-coagulant.

Question 27

How is nitrogen transported in the body?

Answer 27

Via the glucose-alanine cycle.

Question 28

What contains most nitrogen from most to least out of-Glutamate,alpha keto glutarate and glutamine?

Answer 28

Glutamine, Glutamate, alpha keto glutarate.

Question 29

What are the functions of the glucose-alanine cycle?

Answer 29

1) NH4+ from muscles to the liver
2) Transport pyruvate back to the liver from muscles to be converted to glucose by gluconeogenesis so muscles dont have to waste there energy doing this.

Question 30

How is nitrogen transported from the muscles to the liver?

Answer 30

NH4+ is removed from glutamate to make alpha keto glutarate. NH4+ is combined with pyruvate to make alanine. Alanine is transported in the blood to the liver and broken down to pyruvate and NH4+.

Question 31

What is the purpose of the urea cycle?

Answer 31

To convert toxic ammonia to non-toxic urea to be excreted.

Question 32

What are the products of the urea cycle?

Answer 32

Only urea all other products are recycled.

Question 33

How many ATP are used in the urea cycle?

Answer 33

3.

Question 34

What are the steps of the urea cycle?

Answer 34

1) Ornithine +amonia +CO2–> Citrulline
2) Citrulline+ amonia–> arginine
3) Arginine–> ornithine and urea given off. cycles back.

Question 35

What occurs is the urea cycle breaks down?

Answer 35

NH4 concentration increases and is neurotoxic to the brain. Krebs cycle stops.

Question 36

What protein converts arginine to ornithine and urea?

Answer 36

ARG1.

Question 37

What is the immune defense of the liver?

Answer 37

The reticuloendothelial system consisting of kumper cells (specialised macrophages of liver) and monocytes.