Erythropoiesis

Question 1

what engulfs old RBCs

Answer 1

phagocytic cells of liver and spleen

Question 2

what are globular haemoglobin protiens broken into

Answer 2

amino acids which enter the blood stream

Question 3

what is the substrate of bilirubin

Answer 3

haem group (minus iron) is converted to bilirubin

Question 4

where is bilirubin transported to

Answer 4

the liver and secreted into bile

Question 5

what does bilirubin do to urine and faeces

Answer 5

colour them

Question 6

how is iron recycled

Answer 6

it binds to transferrin

Question 7

what is erythrocyte production regulated by

Answer 7

enzyme erythropoietin (EPO)

Question 8

when is EPO released

Answer 8

when there is reduced oxygen carrying capacity

Question 9

where is EPO released from

Answer 9

the kidneys

Question 10

what does EPO do

Answer 10

production of RBC by red bone marrow

Question 11

describe the cells in erythropoiesis from stem to mature cell

Answer 11

proerythroblast, polychromatic, orthochromatic, erythythroblast extrudes nucleus, reticulocyte, mature erythrocyte

Question 12

where is proerythroblast derived from

Answer 12

myeloid stem cells

Question 13

what is the diameter and thickness of a RBC

Answer 13

8um diameter, 2um thick at edge and 1um in the centre

Question 14

what is haematocrit

Answer 14

volume of RBCs as % of total blood volume

Question 15

how is ATP synthesised in RBC

Answer 15

via glycolysis as they have no mitochondira

Question 16

apart from glycolysis what is another pathway for metabolism of glucose

Answer 16

hexose monophosphate shunt

Question 17

what does the hexose monophosphate shunt produce which is important

Answer 17

NADPH (this is important for maintenance of adequate levels of reduced glutathione

Question 18

what does glutathione do

Answer 18

combat oxidative stress

Question 19

what are reactive oxygen species

Answer 19

free radicals that are highly reactive as they have unpaired electrons

Question 20

which ion is particularly reactive

Answer 20

superoxide anion o1-

Question 21

what is the main reactive species

Answer 21

hydrogen peroxide

Question 22

what is required to maintain adequate levels of reduced glutathione

Answer 22

NADPH

Question 23

what is produced when po2 is reduced

Answer 23

2,3 BPG

Question 24

what does 2,3 BPG do

Answer 24

release O2 from Hb

Question 25

what can lack of reduced glutathione be caused by

Answer 25

glucose-6 phosphate dehydrogenase insufficiency and hence NADPH deficiency)

Question 26

where does CO2 bind to in haemoglobin

Answer 26

the globin portion of haemoglobin

Question 27

how is CO2 carried to the lungs

Answer 27

partially dissolved in solution, bound to HB

as a bicarbonate ion

Question 28

how many o2 molecules can each haem group bind

Answer 28

one

Question 29

foetal haemoglobin is predominantly what type

Answer 29

a2y2

Question 30

what happens in late gestation to the globin

Answer 30

y expression falls and b expression rises