Hematopoiesis Overview Quiz

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Questions and Answers

What are the first blood cells formed during the mesoblastic phase of hematopoiesis?

Eosinophilic stem cells

Pluripotential stem cells

Fetal erythroblasts

Primitive erythroblasts (correct)

Which statement best describes the polyphyletic theory of hematopoiesis?

Each blood lineage comes from a unique stem cell. (correct)

The theory is based on the function of the fetal liver.

All blood cells are derived from a single progenitor stem cell.

Blood cells can arise from both yolk sac and bone marrow simultaneously.

During which phase of hematopoiesis is fetal hemoglobin (Hb F) predominantly produced?

Intramedullary phase

Postnatal phase

Hepatic phase (correct)

Mesoblastic phase

At what point in development does hematopoiesis start in the bone marrow cavity?

Before the 5th month of fetal development Signup and view all the answers

Which of the following is a classical marker for hematopoietic stem cells?

CD 34 Signup and view all the answers

Which organ is considered the first fully developed organ in the fetus and a major site of T cell production?

Thymus Signup and view all the answers

Which type of hematopoiesis occurs intravascularly within developing blood vessels?

Mesoblastic hematopoiesis Signup and view all the answers

What is the primary function of primitive erythroblasts during early embryogenesis?

To generate hemoglobin for oxygen transport Signup and view all the answers

Which of the following locations are primary sites for hematopoiesis in adults?

Bone marrow Signup and view all the answers

At what age does the process of retrogression in bone marrow typically occur?

5 to 7 years Signup and view all the answers

What type of marrow is characterized as hematopoietically inactive and contains adipocytes?

Yellow marrow Signup and view all the answers

Which organs are considered primary lymphoid organs where T and B lymphocytes originate?

Bone marrow and thymus Signup and view all the answers

In adults, what proportion of bone marrow is red versus yellow?

50% red, 50% yellow Signup and view all the answers

What is a major function of secondary lymphoid organs like the spleen and lymph nodes?

Trapping and concentrating foreign substances Signup and view all the answers

Which statement accurately reflects the role of yellow marrow during increased physiological demand?

It can revert back to active red marrow. Signup and view all the answers

Which phase of hematopoiesis is characterized by the transition from mesoblastic to hepatic production of blood cells?

Hepatic phase Signup and view all the answers

In adults, which type of bone marrow primarily contributes to hematopoiesis?

Red marrow Signup and view all the answers

At what developmental stage do T and B lymphocytes begin to differentiate in primary lymphoid organs?

Fetal stage Signup and view all the answers

Which statement accurately describes the role of stem cells during hematopoiesis?

They can give rise to multiple blood cell lineages. Signup and view all the answers

Which organ plays a crucial role in the immune response by facilitating the maturation of lymphocytes?

Spleen Signup and view all the answers

What is the primary advantage of a bone marrow biopsy compared to a bone marrow aspirate?

It preserves the architecture of the bone marrow. Signup and view all the answers

What does a myeloid-to-erythroid (M:E) ratio of 10:1 typically indicate?

Presence of leukemia. Signup and view all the answers

In which condition is extramedullary hematopoiesis most likely to occur?

Aplastic anemia. Signup and view all the answers

What constitutes the erythron within the context of erythropoiesis?

The total mass of circulating RBCs and their precursors in the bloodstream. Signup and view all the answers

How long should bone marrow smears be retained for examination?

10 years. Signup and view all the answers

Study Notes

Sample Question

A laboratory student consistently makes wedge-technique blood films that are too long and thin
Correcting the issue would include moving the drop of blood closer to the center of the slide
Increasing the acute angle of the pusher slide

Hematopoiesis

Hematopoiesis is the process of blood cell formation
CD34 is a classical marker for hematopoietic stem cells
Hematopoiesis begins around the 19th day of embryonic development after fertilization

Polyphyletic Theory: Suggests each blood cell lineage originates from a unique stem cell
Monophyletic Theory: Suggests all blood cells originate from a single pluripotential stem cell (PSC)
The most widely accepted theory amongst hematologists is the monophyletic theory

Three Phases of Hematopoiesis

Mesoblastic/Megaloblastic:
- Chief site: Yolk Sac
- First blood cells: Primitive Erythroblasts (PE) produced during the first 2 to 8 weeks of life
- PE are important in early embryo-genesis to produce hemoglobin (Gower-1, Gower-2, and Portland) which is essential for the delivery of oxygen to embryonic tissues
- Yolk sac hematopoiesis occurs intravascularly (within developing blood vessels) which differs from later hematopoiesis occurring in the fetal and adult stages.
Hepatic:
- Chief site: Fetal Liver
- Hemoglobin: Hb F (Fetal hemoglobin) is dominant during the phase
- Organs: Thymus (first fully developed organ in the fetus, increases in size during fetal development, major site of T cell production), Kidneys and Spleen (produce B cells)
Intramedullary/Medullary/Myeloid:
- Chief site: Red Bone Marrow
- Hematopoiesis starts in the bone marrow cavity before the 5th month of fetal development.
- Bone marrow becomes the chief site by the end of 24 weeks' gestation

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Description

Test your knowledge on hematopoiesis, the process of blood cell formation. This quiz covers key concepts such as the phases of hematopoiesis, related theories, and markers for stem cells. Dive into the mechanisms behind blood cell production and evaluate your understanding.