Normal RBCs Flashcards
negatives of RBCs having no nucleus?
cant divide or replace damaged proteins
RBCs have a __ oncotic pressure, why is this?
high
full of Hb
how do RBCs generate energy?
glycolysis
name the 4 subunits of Hb
2 alpha
2 beta
where is iron located in a Hb molecule?
the middle of the haem group
what form of iron is in Hb and why?
Fe2+ to attract 1 oxygen
how many O2 molecules can bind to Hb
4
Fe3+ is the ___ed version of Fe2+
oxygenated
what does Hb do?
delivers O2 to tissues
acts as a buffer for H+ (can take it up if need be)
CO2 transport
red cell destruction occurs where?
spleen
globin chains are recycled to what structures?
amin acids
heme group is recycled to what structures?
iron
bilirubin
aged red cells are taken up by what cells?
macrophages
how are RBCs excreted?
haem group broken down to bilirubin
conjugated by liver
excreted in bile via urine/faeces
name the structures in the haem-bilirubin pathway
heme to porphyrin to biliverdin to bilirubin
how does erythropoetin regulate red cell production?
hypoxia sensed by kidney
erythropoetin made which stimulates red cell production
high RBC count will switch off EPO
why can you get anaemia from renal failure?
erythropoetin is made here which regulates RBC production
how does NADH maintain red cell oxygenation
stops oxidation of iron (a reducing agent) by turning back into NAD+ in glycolysis
what is methaemoglobin?
Fe3+
“blue patient”
methaemoglobin anaemia
what substance can get rid of hydrogen peroxide? what does it convert it to?
glutathione
water
why is hydrogen peroxide a problem for red blood cells
it is a ROS so will oxygenate the cells and cause damage
what substance can replenish glutathione levels?
NADPH
what does the hexose monophosphate shunt mediate?
glutathione production and thus prevents formation of ROS
how does CO2 get from lungs to tissues?
- as HCO3 (most)
- bound to Hb
- dissolved in solution (least)
what effect does Cl entry have on RBCs
it swells them
how does fetal Hb differ from adult Hb
has 2 gamma groups instead of 2 beta groups
describe the shape of the O2-haemoglobin curve
sigmoidal
what is O2 sat of haemoglobin like in the lungs?
v high
oxygen binding to Hb has an allosteric/antagonistic effect
allosteric
1 oxygen bound makes the next O2 binding easier and so on
fetal Hb can saturate more/less oxygen at a respective PO2 than adult
more (needs more from maternal circulation)
monomeric myoglobin takes O2 from what structures?
red cells
2,3-DPG is the same as 2,3-BPG T or F
T
what shifts O2 dissociation curve to the right?
low pH - oxygen RELEASED to tissues
high DPG
high temp
what shifts O2 dissociation curve to the left
high PH
low DPG
low temp
2,3-DPG is ___ed in chronic anaemia
increased
components of CADET face RIGHT?
CO2 acidosis 2,3-DPG exercise temp
