Lecture 2

Question 1

In adults, where does hematopoiesis predominately occur?

Answer 1

Bone marrow

Question 2

What are the 3 lineages of hematopoiesis?

Answer 2

Myeloid lineage

Erythroid lineage

Lymphoid lineage

Question 3

1. Which lineage is represented by the RED box?
2. Which lineage is represented by the BLUE box?

Answer 3

1. Lymphoid lineage
2. Myeloid lineage

Question 4

Where does hematopoiesis take place in older animals?

Answer 4

Still in the bone marrow, but more towards the ends of the long bones

Question 5

Bone marrow histology changes with age. Which of the following cellularities is related to a younger animal and which is related to an older animal?

1. Hypocellular?
2. Hypercellular?

Answer 5

1. Hypocellular = older animal
2. Hypercellular = younger animal

Question 6

1. More specifically, where within the bone trabeculae does hematopoiesis occur in mammals?
2. In avians?

Answer 6

1. Hematopoietic spaces
2. Venous sinuses

Question 7

Explain the pathway of blood cells from the hematopoietic space of the bone into circulation.

Answer 7

Hematopoietic space –> venous sinus –> central vein –> circulation

Question 8

Which type of cells are integral to healthy bone marrow and responsible for keeping immature blood cells from entering circulation?

Answer 8

Reticular (adventitial) cells

Question 9

What type of division do stem cells undergo?

Answer 9

Asymetric division

Question 10

A multipotential stem cell can divide into which two types of cells?

Answer 10

Lymphoid stem cell

OR

Myeloid stem cell

Question 11

Before becoming a erythrocyte, a myeloid stem cell differentiates into which 2 cell types?

Answer 11

BFU-E (blast-forming unit erythroid)

&

CFU-E (colony-forming unit erythroid)

Question 12

About what percentage of old RBCs are destroyed each day in a healthy animal?

Answer 12

1 %

Question 13

1. In which organ is erythropoietin produced in the ADULT?
2. Which cells of that organ are involved in the production?
3. In which organ is erythropoietin produced in the FETUS?

Answer 13

1. Adult = kidney
2. Peritubular interstitial cells
3. Fetus = liver

Question 14

What stimulates the kidneys to produce erythropoietin in an adult animal?

Answer 14

Hypoxia

Question 15

On which cells does erythropoietin have the greatest effect?

Answer 15

BFU-E

&

CFU-E

Question 16

What are 3 factors that promote erythropoiesis? (there are 7 total)

Answer 16

1. Erythropoietin
2. SCF (stem cell factor)
3. IL-3, IL-9, IL-11
4. G-CSF, GM-CSF
5. Thyroxine
6. Growth hormone
7. Androgens

Question 17

What are the 4 factors that inhibit erythropoiesis?

Answer 17

TNF-alpha

IL-6

TGF-beta

Estrogen

Question 18

What is the first cell in erythropoiesis to be identified as a RBC precursor?

Answer 18

Rubroblast

Question 19

1 rubrioblast produces how many RBCs?

Answer 19

16

Question 20

As hemoglobin synthesis increases, DNA synthesis ____.

Answer 20

As hemoglobin synthesis increases, DNA synthesis decreases.

Question 21

List, in order, the cell types involved in the differentiation process of a rubriblast to a mature erythrocyte.

Answer 21

Rubriblast

Prorubricyte

Rubricyte (early, middle, late)

Metarubricyte

Reticulocyte

Erythrocyte

Question 22

At which cell type within hematopoiesis does hemoglobin synthesis begin?

Answer 22

Early rubricyte

Question 23

At which cell type within hematopoiesis does hemoglobin synthesis stop?

Answer 23

Late rubricyte

Question 24

At which cell stage in hematopoiesis is the nucleus extruded from the cell?

Answer 24

Metarubricyte

Question 25

At which cell stage in hematopoiesis is the cell released from the bone marrow?

Answer 25

Reticulocyte

Question 26

From the metarubricyte, which cell type takes up the extruded nucleus?

Answer 26

Macrophage

Question 27

What are the 2 main functions of the erythrocyte?

Answer 27

1. Transport O2 2. Transport CO2

Question 28

Name 2 changes that occur to erythrocytes as they age.

Answer 28

1. Enzyme content changes 2. Cell membrane structure/surface markers change

Question 29

What is extravasular hemolysis?

Answer 29

When macrophages remove RBCs from circulation within the spleen, liver, or bone marrow

Question 30

True or False: 1. Cats have a closed splenic circulation. 2. Cats are more efficient at RBC removal. 3. Cats have a rather large RBC reserve pool.

Answer 30

1. TRUE 2. FALSE - cats are LESS efficient at RBC removal 3. FALSE - cats LACK large RBC reserve pools