Blood 3 Flashcards
how much ml/ day of RBC is produced
Produces about 30mL/day (>10^6 RBC/second)
why is it important circulating erythrocytes to remain constant?
too few RBC’s leads to hypoxia (not enough o2 in tissues)
too many RBC’s cause undesirable blood viscosity
how does our body control erythropoiesis
erythropoietin (EPO) release by kidney
what cause EPO to be released by the kidney
- hypoxia due to low RBCs
- decreased oxygen availability
- increased tissues demand for oxygen
ALL BASED-ON OXYGEN AVAILIBILITY
what happens when erythropoiesis is enhanced?
RBC count is going up
oxygen carrying ability increases
reticulocyte count increase indicating increase RBC synthesis
why do dialysis patients become anemic
kidneys aren’t working so they cannot sense oxygen levels anymore, so they do not produce erythropoietin, leading to anemia
dietary requirements for erythropoesis
proteins, lipids, carbohydrates, iron, vitamin b, folic acid
where is iron stored in the body?
Hb (65%), the liver, spleen, bone marrow, ferritin and hemosiderin
what happens if iron is circulating
it binds to transfferin
what is the life span of erythrocytes in circulation
100-120 day
Old RBCs become rigid and fragile, and their Hb begins to disintegrate why?
they have no nucleus
what happens to dying RBCs
they are taken up buy macrophages in the spleen or liver (sometimes)
what happens to the iron in the Hb
the heme and globin are broken down into their constituents and the iron is salvaged
what happens when heme is degraded
1.iron is stripped, its degraded to bilirubin
2. liver secretes bilirubin into intestine bile
3. intestine metabolizes it to urobilinogen
4. leaves as feces brown pigment called stercobilin
what happens when someone is jaundice
it comes from bilirubin since the liver cannot process it making the person yellow. it can be occasional in newborns. drink water
