Normal red cells Flashcards
do red blood cells have a nucleus?
no
red blood cells are full of ________ to carry oxygen
haemoglobin
do red blood cells have mitochondria?
no
can red blood cell divide
nope, can’t divide, can’t replace damaged proteins, limited lifespan
why are red blood cells flexible
to squeeze through capillaries (the cells are bigger than the capillaries)
haemaglobin function
- deliver oxygen to tissues
- act as a buffer for H+
- CO2 transport
do we want to keep water in or out of red blood cells
out (we do this by the sodium-potassium pump)
how many subunits is haemoglobin made of
4 (2 alpha and 2 beta)
what state does iron need to be in to carry oxygen?
Fe2+
(oxygen does NOT bind to Fe3+)
red cell production is regulated by ____________
erythropoietin
what makes the hormone erythropoietin?
kidney
hypoxia sensed by kidney —-> __________ produced —-> __________ stimulates red cell production
erythropoietin
where does red cell destruction normally occur?
spleen (and liver)
what is the average red cell lifespan
120 days
aged red cells are taken up by _________
macrophages
red cell contents are recycled, true or false
true
old red cells - what are globin chains recycled to?
amino acids
old red cells - heme group broken down to ____ and _________
iron and bilirubin
old red cells - bilirubin is taken to _____ and conjugated
liver
what is the glucose to lactate process/pathway is called?
glycolysis or Embden-Meyerhof pathway
in glycolysis, _____ acts an electron donor preventing
oxidation of
Fe 2+ to Fe 3+
and generating
NAD+ in the process
NADH
_______ protects us from hydrogen peroxide, defense against oxidative damage
glutathione (GSH)
what is the rate limiting enzyme in the process of glutathione reacting with hydrogen peroxide to protect us from oxidative damage?
G6PD
what does a red cell need?
- a way of generating energy i.e. ATP
- a way to keep Fe2+ from becoming Fe3+ (ie stop it oxidising)
- a way to prevent oxidative damage to cellular enzymes and Hb from free radicals
- a way of buffering CO2 for transport
- a way of holding onto oxygen in transport and dumping it in hypoxic environments
- a way of improving tissue oxygen delivery when it needs it most (when anaemic or when high demand for oxygen)
red cell - is osmotic pressure high or low
high (it is stuffed with Hb)
oxygen binding to Hb kinetics - the allosteric effect
as first oxygen binds to a haem in one subunit, the Hb shape changes
this alters how easy it is for the next O2 to bind to the haem in the next subunit
and this changes the shape again…
therapeutically this is helpful.
fetal Hb subunits
has 2 alpha and 2 gamma subunits
what can hold onto oxygen better - adult or foetal haemaglobin?
foetal
what is 2,3 BPG
a small molecule found in red blood cells
2,3-BPG binds to hemoglobin molecules within red blood cells, causing a conformational change that decreases the affinity of hemoglobin for oxygen.
allows more oxygen to be delivered to tissues in stressful situations??
it is increased in chronic anaemia
