physiology Flashcards
What does EPO do?
Controls RBC production and increases circulating reticulocyte count as well as maturation of committed HSC
How are RBCs destroyed?
Old cells are removed by a filtration system in the reticulo-endothelial system (spleen, liver and bone marrow)
They are phagocytosed by macrophages
How are cells chose to be removed?
Reduced flexibility
Altered membrane surface
Rupture
What percentage of plasma is water?
90%
What percentage of plasma is protein?
7%
What does albumin bind to?
Just about everything from cations, FFA, to bilirubin and hormones
What do chylomicrons do?
Produced in gut and distribute dietary lipids to rest of the body
They are taken up by the liver as CMRs (chylomicron remnants)
What are LDLs?
Low density lipoproteins produced in the liver, loaded with liver lipids, distribute lipids to the rest of the body.
What are HDLs?
Produced in the liver but are empty and pick up cholesterol from the rest of the body
How are LipoProteins unloaded?
2 ways:
- Unload lipids from lipoprotein (enzyme-catalysed removal of lipids, TGs require lipoprotein lipase enzyme (LPL), chol only from HDLs via SRB1)
- Remove entire lipoprotein via endocytosis after LPR receptor binding. (this is seen in the liver mostly)
What does lipoprotein lipase enzyme do?
Found in muscle , adipose tissue, heart, mammary glands and liberates FFAs from TGs FFAs are then removed from LPs
What are apolopoproteins?
Ligands for cell surface receptors.
apoB is required for cellular uptake of CMs and LDLs
Which apoprotein is found on ChyloMicrons?
apoB48
Which apoproteins are found on LDL?
apoB100
What happens to apoprotein cofactors?
They are recycled between circulating LPs (they are swapped)
What does LDL contain?
Lots of cholesterol