Lec 1 Hematopoesis

Question 1

What is the equation for MCV?

Answer 1

MCV = hematocrit / erythrocyte count (RBC x 10^6)

Question 2

What is MCV?

Answer 2

mean corpuscular volume = average size of RBC

Question 3

What is the equation for MCH?

Answer 3

MCH = hemoglobin / erythrocyte count (RBC x 10^6)

Question 4

What is MCH?

Answer 4

mean corpuscular hemoglobin = average amount of hemoglobin per cell

Question 5

What is life span of RBCs?

Answer 5

4 months

Question 6

What are the components of plasma?

Answer 6

proteins, immunoglobulins [antibodies], clotting factors, anti-coagulants

Question 7

What are the components of the buffy coat?

Answer 7

platelets and white blood cells

Question 8

What is normal hematocrit %?

Answer 8

40-50%

Question 9

What is the difference plasma and serum?

Answer 9

serum does not contain clotting factors

Question 10

How do you measure hematocrit?

Answer 10

multiple # of RBCs x mean corpuscular volume

Question 11

What is an equation for MCV?

Answer 11

hematocrit / erythrocyte count (RBC x 10^6)

Question 12

What is an equation for mean corpuscular hemoglobin?

Answer 12

hemoglobin / erythrocyte count (RBC x 10^6)

Question 13

What does the worse anisocytosis mean?

Answer 13

variation in RBC size

Question 14

When might leukocyte count be falsely elevated?

Answer 14

in presence of clumped/aggregated platlets, nucleated RBCs, or non-lysed RBCs

Question 15

When might platelet count be falsely low?

Answer 15

when platelets are clumped by agglutinins [pseudothrombocytopenia]

Question 16

What is normal reticulocyte %?

Answer 16

1%

Question 17

What dye can you use to stain reticulocytes?

Answer 17

methylene blue = stains residual RNA present in young RBCs

Question 18

What is the corrected reticulocyte count?

Answer 18

multiple retic count x observed hematocrit / normal hematocrit

normal = 45%

Question 19

What is the absolute reticulocyte count?

Answer 19

actual number of reticulocytes in given volume of blood

retic count x total RBC count

Question 20

What does low retic count suggest?

Answer 20

problem with bone marrow production of RBCs

Question 21

What does normal/high retic count suggest in anemia?

Answer 21

cause of anemia related to destruction of RBCs after they leave the bone marrow

Question 22

What is myelopoiesis?

Answer 22

development of cells of myeloid lineage [RBCs, platelets, neutrophils, monocytes, eosinophils, basophils]

Question 23

What is erythropoiesis?

Answer 23

development of RBCs

Question 24

What is megakaryopoiesis?

Answer 24

development of megakaryocytes and platelets

Question 25

What is lymphopoiesis?

Answer 25

development of cells of lymphoid lineage --> B and T cells

Question 26

Where does lymphopoiesis occur in adult?

Answer 26

spleen lymph nodes thymus gut-associated lymphoid tissue

Question 27

What is sequential location of hematopoiesis in fetal development? [hint: 5 locations]

Answer 27

- yolk sac - aorta-gonad mesonephros region - liver - spleen - bone marrow

Question 28

Wat is definitive hematopoiesis? Where does it begin?

Answer 28

forming nucleated RBCs which synthesize fetal hemoglobin begins in liver

Question 29

After birth where does hematopoiesis occur?

Answer 29

only in bone marrow

Question 30

Can you see stem cells in the bone marrow?

Answer 30

not morphologically identifiable | one in 10^6 nucleated marrow cells is a stem cell

Question 31

What is the order of cell development to form differentiated RBC?

Answer 31

stem cell --> multi-lineage progenitor --> uni-lineage progenitor --> identifiable precursor --> circulating mature cell

Question 32

How do hematopoietic cells differ from other cells in body?

Answer 32

- short life span - multiple cell ypes - cells widely distributed throughout body - hematopoiesis can occur quickly in emergencies - cells must be replaced daily

Question 33

How can you identify hematopoietic stem cells?

Answer 33

cell surface antigen CD34

Question 34

How can you identify progenitor cells?

Answer 34

not morphologically identifiable can use in vitro assay cell surface antiges CD34

Question 35

How can you identify precursor cells?

Answer 35

morphologically identifiable

Question 36

What is normal distribution myeloid to erythroid precursor ratio in bone marrow?

Answer 36

normally 3 to 3.5:1 | myeloid --> become granulocytes, monocytes, neutrophils

Question 37

What is the action of stromal cells in the bone marrow?

Answer 37

create cellular matrix | produce cytokines and hematopoietic growth factors [HGFs]

Question 38

What makes of the bone marrow extracellular matrix? Function?

Answer 38

fibronectin, proteoglycans, collagen bring cytokines/growth factors and progenitor cells together

Question 39

Where is erythropoietin produced?

Answer 39

kidney act on bone marrow erythroid cells

Question 40

Where is thrombopoietin produced?

Answer 40

liver acts on megakaryocytes in bone marrow = platelet precuroors

Question 41

What is action of plerixafor?

Answer 41

inhibits interaction between stromal derived factor 1 [SDF-1] and its receptor chemokine receptor 4 [CXCR4] --> release of hematopoietic stem cells from the bone marrow into peripheral blood