During the second trimester of pregnancy, where is the predominant site of RBC production?

• Yolk sac

• Bone marrow

• Lymph nodes

• Liver

What function do vitamin B12 and folic acid perform that is critical to hematopoiesis?

• Support porphyrin production

• Serve as cofactors for iron uptake

• Support terminal differentiation of erythroid and myeloid cells

• Support production of thymidine triphosphate

Answer explanation

Cell proliferation requires DNA replication, which requires an adequate supply of thymidine triphosphate. Both vitamin B12 and folate are needed to make thymidine triphosphate.

Ishika, Advait, and Akhil are astronauts preparing for a mission to Mars. They are curious to know, after being placed in an atmosphere with low oxygen, how long does it take for increased numbers of reticulocytes to develop in their bodies?

• 6 hours

• 12 hours

• 3 days

• 7 days

Answer explanation

EPO levels increase after a decreased arterial oxygen level, with the maximum EPO production occurring within 24 hours. It takes 3 days for new reticulocytes to appear in the circulation, and after a total of 5 days from the beginning of hypoxemia, these reticulocytes will be circulating as mature erythrocytes. Because it takes 1 to 2 days for a reticulocyte to become an erythrocyte, the correct answer is 3 days until the person has an increased number of reticulocytes.

What is the first stage of erythropoiesis?

• Erythroblast

• Proerythroblast

• Normoblast

• Reticulocyte

2. Which organ primarily produces the hormone erythropoietin (EPO)?

• Heart

• Liver

• Kidneys

• Lungs

What does the presence of nucleated red blood cells in a sample of bone marrow indicate?

• Healthy erythropoiesis

• Underproduction of red blood cells

• Dehydration

• Release of incompletely developed cells due to excess demand

A 45-year-old patient presents with chronic kidney disease and is experiencing anemia. The physician recommends erythropoietin (EPO) therapy to stimulate erythropoiesis. How does EPO therapy primarily affect erythropoiesis?

• It increases the number of reticulocytes in the bloodstream.

• It reduces the production of white blood cells.

• It enhances the absorption of iron from the gastrointestinal tract.

• It promotes the breakdown of old red blood cells in the spleen.

1. Erythropoiesis primarily occurs in the ________ in adults.

During------------------ stage of erythropoiesis the nucleus is extruded.

The final stage of erythropoiesis is the production of a(n) ________, which is released into the bloodstream