5: Erythrocyte Functions/Destruction

3 major functions of erythrocytes

tranport O2, CO2, buffer H ions

P50

pO2 when hemoglobin is 50% saturated

higher O2 affinity =

lower P50

lower O2 affinity =

higher P50

what does 2,3 DPG do?

decreases hemoglobin O2 affinity inside RBCs

70% of CO2 transported

bicarb

25% of CO2 transported

carbamino groups

major protein buffer in blood

hemoglobin

what is weaker, deoxyhemoglobin or oxyhemoglobin?

DEOXYhemoglobin

alloantigens (isoantigens)

self-antigens with differences in production at certain chromosomal loci with 2 or more allelic genes

dog blood group antigen

DEA 1

cat blood group antigen

AB and Mik

horses blood group antigen

Q+A factors

natural antibodies

present without prior transfusion/pregnancy. IMPORTANT IN CATS

why are natural antibodies important in cats?

B+ cat has STRONG anti-A antibodies, A+ cat has weak anti-B antibodies

after a mismatched transfusion, when do we expect to see antibodies?

3-5 days later

what do RBCs lack

nuclei, ribosomes, mitochondria, ER

90-95% of glucose comes from what

glycolysis

what protects erythrocytes from oxidative injury?

NADPH. glutathione, antioxidant enzymes

what does oxidative injury affect?

Hb

what causes Hb injury?

methemoglobin and Heinz bodies

can methemoglobin bind O2?

NO

what are Heinz bodies?

oxidized, denatured hemoglobin

true or false: larger mammals tend to have longer RBC lifespan

TRUE

is RBC loss random?

NO

lifespan of RBCs in domestic mammals

2-5 months

RBC lifespan in birds

30-45 days

RBC lifespan in turtles

600-800 days

what do aging RBC affect?

membrane changes (phopholipids/carbs)

what contributes to RBC aging?

O2 injury

extravascular hemolysis

destruction of RBCs outside of a blood vessel (usually in spleen)

what usually INCREASES with RBC destruction?

bilirubin