GI Liver storage Flashcards
Which vitamins are fat soluble?
A, D, E, and K. Allows them to be more eaisly stored in the body.
What regulates free Fe3+ in the body?
Transferrins in plasma.
Where is dietary iron used?
For myoglobin in muscles, bone marrow for hemoglobin production, the liver.
Where is dietary iron stored?
The liver parenchyma.
What is the process for the breakdown of erythrocytes?
Reticulo-endothelial macrophages break down haemoglobin to produce free Fe3+.
What are the types of dietary iron?
Heme associated and free Fe3+.
How is heme associated iron absorbed?
It enters the cell through a heme transporter and can then
How is heme associated iron absorbed?
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.
What is the role of Cytochrome B in the absorption of dietary iron?
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.
What is the transporter for free iron Fe2+ into the cell?
DMT1. Divalent metal transporter 1.
What is the transporter for iron out of the cell?
Ferroportin 1.
How is dietary B12 protected against gastric juice?
It is bound to R protien.
Where is R protein made?
The salivary glands and the stomach.
When is R protein removed from B12 and by what?
Pancreatic enzymes remove the R group in the duodenum/ jejunum.
What allows B12 to be absorbed?
Intrinsic factor.
Where is intrinsic factor produced?
The parietal cells of the stomach.
Where is B12 absorbed?
In the ileum as it can bind to intrinsic factor receptors.
How is B12 metabolised?
In the liver B12 is part of the cycle which allows the production of folate for nucleic acid synthesis and methyonine for reactions.
How and where is vitamin A metabolised?
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.
How and where is vitamin D metabolised?
Cholecaliciferol is metabolised in the liver to form inactive hydroy-vitamin D3 which is then activated in the kidneys to dihydroxy- vitamin D3.
Which protiens are produced by the liver?
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.
What happens to excess amino acids?
They are metabolised and there skeleton used in alpha keto acids.
What is alpha keto acids importance?
It is an important electron exchanger in the krebs cycle.
What stimulates glutamate+h2O conversion to alpha keto glutarate?
Decreased energy= increased ADP= increased alpha keto glutarate. More alpha keto acid so more krebs so more energy.
