Erythropoiesis: RBC Production

Question 1

Where are RBCs produced?

Answer 1

In the bone marrow

Question 2

What is the RBC stages of development?

Answer 2

Stem cell –> Rubriblast –> Prorubricyte –> Rubricyte –> Metarubricyte –> Polychromatophil –> Mature RBC

Question 3

How long does the maturation process take?

Answer 3

3-4 days

Question 4

What is RBC production stimulated by??

Answer 4

Decreased arterial partial pressure of oxygen (PO2), which leads to tissue hypoxia in the kidneys.

Question 5

What hormone stimulates RBC production and what organ releases it?

Answer 5

Erythropoietin, released by the kidney

Question 6

What happens if there are increased levels of erythropoietin?

Answer 6

Hemoglobin synthesis starts earlier and cell divisions may be skipped, resulting in larger (immature) RBCs (shift red cells)

Question 7

What happens if RBC production is decreased, or more destruction occurs?

Answer 7

Anemia

Question 8

What can slow down RBC production?

Answer 8

Increases in renal oxygen tension

Question 9

What is the approximate RBC circulating lifespan in cats and dogs?

Answer 9

~100 days in dogs
~85-90 days in cats

Question 10

Approximately when is the entire blood supply of RBCs replaced?

Answer 10

About every 30 days

Question 11

What are the primary functions of RBCs?

Answer 11

1. Accumulate oxygen from lungs
2. Transport and release oxygen
3. Replace released oxygen with waste gas
4. Transport CO2 to lungs

Question 12

What is blood plasma composed of?

Answer 12

90% water
10% dissolved substances

Question 13

What are RBCs composed of?

Answer 13

65% water
5% organelles, enzymes, salt
30% hemoglobin

Question 14

What are common RBC morphology features?

Answer 14

• Rouleaux, stacking
• Anisocytosis, size variation
• Poikilocytosis, shape variation

Question 15

What are the 5 categories of RBC morphology changes?

Answer 15

1. Regenerative changes
2. Immune-mediated damage
3. Oxidative injury
4. Membrane/metabolic disorder
5. Mechanical fragmentation

Question 16

What does the Regenerative Change sub-group contain?

Answer 16

Cells which have appeared due to anemia, generally includes immature cells:
1. Polychromatic RBC
2. Reticulocytes
3. Shift RBC
4. nRBC
5. Howell-Jolly body
6. Basophilic stippling
7. Anisocytosis

Question 17

What does the Immune-Mediated Damage sub-group contain?

Answer 17

Contains RBCs that are being targeted by the immune system:
1. Ghost cell
2. Spherocyte
3. Agglutination

Question 18

What does the Oxidative Injury sub-group contain?

Answer 18

Occurs when hemoglobin is oxidized and denatured due to disease or drugs:
1. Erythrocyte Refractile Bodies (ER Bodies)
2. Heinz body
3. Eccentrocyte

Question 19

What does the Metabolic/Membrane Disorder sub-group contain?

Answer 19

Due to environmental disorder:
1. Echinocytes
2. Crenated cell
3. Burr cell
4. Acanthocyte
5. Blister cell
6. Keratocyte
7. Sickle cell
8. Hypochromasia
9. Elliptocyte (Ovalocyte)
10. Leptocyte
- Leptocyte: Torocyte
- Leptocyte: Stomatocyte
- Leptocyte: Target Cell (Codocyte)
- Leptocyte: Bar cell (Knizocyte)

Question 20

What does the Mechanical Fragmentation sub-group contain?

Answer 20

Results from mechanical damage:
1. Schistocytes (Schizocytes)
2. Dacryocyte

Question 21

What are the 3 most common RBC parasites in dogs?

Answer 21

1. The Hemotropic mycoplasma; Mycoplasma hemocanis
2. Babesia canis
3. Babesia gibsoni

Question 22

What are the 3 most common RBC parasites in cats?

Answer 22

1. The Hemotropic mycoplasma; Mycoplasma hemofelis
2. Candidatus mycoplasma sp.
3. Cytauxzoon felis

Question 23

3 RBC tests?

Answer 23

1. Coomb’s Test
2. Erythrocyte Sedimentation Rate
3. Autoagglutination

Question 24

What does the Coomb’s Test test for?

Answer 24

For Immune-mediated hemolytic anemia

Question 25

What does the Autoagglutination test for?

Answer 25

Immune-mediated hemolytic anemia