260b Erythropoiesis Flashcards Preview

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Flashcards in 260b Erythropoiesis Deck (25):
1

Erythron

progenitor + mature RBC; continuously renew from BM

2

Erythropoiesis

kidneys release EPO based on oxygen tension (low O2 tension increased HIF-1 transcription factor --> activates EPO gene expression)

goes to BM to make new RBCs

3

reticulocyte

early RBC from BM in blood

4

hematocrit - what is it? what does dehydration do? hemorrhage?

packed RBC volume compared to total blood volume (aka RBC concentration)

dehydration increases hemtocrit due to less plasma

hemorrhage - no change in RBC concentration in the first few hours (both plasma and RBC lost), after a few hours the plasma volume increases which decreased Hct for ~ 30 days (until RBC are made again)

5

anemia

decreased hemoglobin/Hct

6

polycythemia

increased RBC count

7

reticulocytosis

increased young RBCs

8

mean corpuscular volume (MCV)

size of RBC
micro/normo/macro

9

mean corpuscular hemoglobin concentration (MCHC)

amount of Hb in RBC

normo/hypo

10

erythroid precursors in BM - how long does this take?

process takes 2 weeks --> reticulocytes 0-3 days in BM --> ~ 1 day in circulation (unless due to anemia then 2-4 days)

11

mature RBC life cycle

120 days in circulation

12

reticulocytes

immature RBCs

no nucleus, but still have mitochondria, ribosomes, golgi, etc

stain with methylene blue OR have solid red color unlike normal RBC with white center

13

RBC - shape, content, membrane features, E?

biconcave w/out nucleus or mito

Hb makes up 33%

membrane allow pliability

E via glycolysis

14

hemoglobin

tetramer with 4 heme groups - each can bind O2 molecule

synthesizes in BM

heme = Fe bound to protoporphyrin in mito

protein globin from cytoplasmic ribosome binds heme to form Hb in cytoplasm

**globin determines type of Hb**

15

RBC - shape, content, membrane features, E?

biconcave w/out nucleus or mito

Hb makes up 33%

membrane allow pliability

E via glycolysis

16

hemoglobin

tetramer with 4 heme groups - each can bind O2 molecule

heme = Fe bound to protoporphyrin
protein globin binds heme

globin determines type of Hb

17

chromosomes of globins

non-a (B) = 11

a = 16

18

RBC degradation

Mo in BV, BM, spleen, liver eat old RBCs via phagocytosis

Globin --> reusable aa's
Fe
heme --> bilirubin --> binds albumin --> liver --> conjugated with glucuronic acid --> bile

19

excess porphyrin is stored how?

complexed to zinc

20

RBC degradation

Mo in BV, BM, spleen, liver eat old RBCs via phagocytosis

Globin --> reusable aa's
Fe
heme --> bilirubin --> binds albumin --> liver --> conjugated with glucuronic acid --> bile

21

what increases O2 dissociation from Hb?

shifts O2 sat curve to the right (sat on y axis, PO2 on x axis)

increased:
Temp
H+ concentration (lower pH) - Bohr effect
CO2
2,3 - BPG (stimulated by deoxyhemoglobin)

22

normal Hb saturation

arterial - 95 mmHg, >97%

venous - 40 mmHg, 75%

23

what increases O2 dissociation from Hb?

shifts O2 sat curve to the right (sat on y axis, PO2 on x axis)

increased:
Temp
H+ concentration (lower pH) - Bohr effect
CO2
2,3 - BPG (stimulated by deoxyhemoglobin)

24

fetal Hb vs maternal Hb dissociation curve?

fetal is shifted left -- much highter affinity for O2

at same PO2, fetal Hb binds more O2 to get a higher percent saturation

24

fetal Hb vs maternal Hb dissociation curve?

fetal is shifted left -- much highter affinity for O2

at same PO2, fetal Hb binds more O2 to get a higher percent saturation