Block 2b Erythrocytes

Question 1

Give dimensions of a RBC.

Answer 1

7.8 x 2.5 microns; 1 micron at center

Question 2

What is hematocrit?

Answer 2

fraction of blood volume taken up by RBCs

Question 3

What is a normal adult Hct?

Answer 3

0.4 - 0.45

Question 4

What is normal hematocrit in a neonate?

Answer 4

0.65

Question 5

Normal RBC concentration in blood?

Answer 5

4.7 - 5.2 x 10^6 cells/uL

Question 6

Which long bones produce RBCs?

Answer 6

tibia & femur

Question 7

which bones produce RBCs in adults?

Answer 7

vertebrae, sternum, rib

Question 8

When do long bones cease RBC production?

Answer 8

20 years old

Question 9

What does pluripotent mean?

Answer 9

cell type that can differentiate into a LIMITED number of cell types

Question 10

What does totipotent mean?

Answer 10

cell type that can differentiate into ANY cell type

Question 11

What is pernicious anemia?

Answer 11

decreased RBC concentration caused by failure to absorb B12

Question 12

What dietary elements are required for RBC production?

Answer 12

B12, folate

Question 13

Where is EPO released?

Answer 13

kidney

Question 14

What is the stimulus for EPO release?

Answer 14

hypoxic tissue

Question 15

What is the effect of EPO and what is the timeframe of its effect?

Answer 15

hematopoiesis over period of days

Question 16

What cell type does EPO drive production of?

Answer 16

proerythrocytes

Question 17

What polypeptides make up HbA?

Answer 17

2 alpha, 2 beta

Question 18

What are the polypeptide chains that can make up Hb?

Answer 18

alpha, beta, gamma, delta

Question 19

What constitutes a polypeptide “chain” in Hb?

Answer 19

polypeptide + heme

Question 20

How many iron atoms are contained in 1 Hb?

Answer 20

4

Question 21

How is iron degraded?

Answer 21

Kupffer cells in liver degrade Hb to Fe + bilirubin; lost in blood & feces

Question 22

How is iron sequestered in cells?

Answer 22

ferritin

Question 23

How is iron sequestered in the blood?

Answer 23

transferrin

Question 24

Where does transferrin act?

Answer 24

plasma and intestines

Question 25

How is iron absorbed?

Answer 25

binds apotransferrin (from bile) to form transferrin, which enters intestinal epithelium thru the transferrin receptor

Question 26

What is the lifespan of a RBC?

Answer 26

120 days in the plasma

Question 27

What is aplastic anemia?

Answer 27

anemia caused by loss of bone marrow

Question 28

What is megablastic anemia?

Answer 28

anemia caused by misshapen RBCs via B12 or folate deficiency

Question 29

What is hemolytic anemia?

Answer 29

anemia caused by fragile RBCs (sickle, erythroblastosis fetalis, spherocytosis)

Question 30

What is polychthemia vera?

Answer 30

failure to suprress RBC production leading to increases in BV and plasma colloid osmotic pressure

Question 31

What scenarios can cause polycythemia?

Answer 31

primary scenario (adaptive response to altitude, cardiac failure), polycythemia vera, or EPO

Question 32

What are functions of RBCs?

Answer 32

transport of Hb, blood buffering

Question 33

What are the types of signaling molecules that may act on PHSCs?

Answer 33

growth inducers and differentiation inducers

Question 34

What is the effect of a growth inducer signaling molecule?

Answer 34

promotes clonal expansion of committed cells

Question 35

What is the effect of a differentiation inducer as a signaling molecule?

Answer 35

drives pluripotent stem cells to committed cells

Question 36

What is an example of a growth inducer?

Answer 36

Il-3

Question 37

What cell types can PHSCs differentiate to?

Answer 37

CFU-S (spleen); or lymphoid stem cell

Question 38

CFU-S cells are precursors to these cells:

Answer 38

CFU-blast, CFU-GM, CFU-M (innate immunity cells & RBCs)

Question 39

CFU-blasts go on to produce:

Answer 39

proerythrocytes

Question 40

How do proerythrocytes change to produce an RBC?

Answer 40

1) nucleus condensed and extruded, 2) ER and Golgi resorbed over 48 hours, 3) RBC leaves bone marrow

Question 41

What are granulocytes?

Answer 41

neutrophils, eosinophils, basophils

Question 42

From what cell type are platelets formed?

Answer 42

megakaryocytes

Question 43

From what cell type are macrocytes formed?

Answer 43

monocytes