As blood cells mature in the marrow, which change in the nucleus is typical?

Chromatin condenses and nucleoli disappear

Chromatin becomes finer and more open

The nucleus-to-cytoplasm ratio increases

Nucleoli become larger and more numerous

In a healthy adult, active red marrow is found mainly in the:

Pelvis, sternum, vertebrae and ribs

Small bones of the hands and feet

Plerixafor is given before apheresis to release hematopoietic stem cells from the marrow into the blood. Which receptor does it block?

The thrombopoietin receptor (c-Mpl)

The main cytokine that drives eosinophil production in the marrow is:

Granulocyte colony-stimulating factor

Macrophage colony-stimulating factor

A 4-month-old has had skin abscesses and pneumonia since birth. Every count shows an absolute neutrophil count of 0.1 × 10^9/L (lower limit for age about 1.0 × 10^9/L) with normal red cells and platelets. The marrow has normal numbers of myeloblasts and promyelocytes but almost no myelocytes, metamyelocytes, bands or neutrophils. These findings are best described as:

Maturation arrest at the promyelocyte stage

Peripheral destruction of mature neutrophils

Normal marrow with neutrophils held in tissues

Failure of the stem cell in all lineages

Hematopoiesis and cell maturation

13 DOH Abu Dhabi (HAAD) lab licensing practice questions on Hematopoiesis and cell maturation, part of Hematology. The first 13 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
As blood cells mature in the marrow, which change in the nucleus is typical?
1. AChromatin becomes finer and more open
2. BThe nucleus-to-cytoplasm ratio increases
3. CNucleoli become larger and more numerous
4. DChromatin condenses and nucleoli disappear
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Answer: D · Chromatin condenses and nucleoli disappear
In general, maturing blood cells become smaller, their chromatin becomes coarser and more condensed, and their nucleoli disappear. The nucleus-to-cytoplasm ratio falls and the cytoplasm becomes less blue as ribosomes are lost, so blasts show fine, open chromatin with visible nucleoli. Megakaryocytes are the exception, growing larger as they mature. These general rules help place an unfamiliar cell in its lineage and stage.
- A: Fine, open chromatin is a feature of immature cells such as blasts.
- B: The nucleus-to-cytoplasm ratio falls as cells mature.
- C: Visible nucleoli belong to immature cells and disappear with maturation.
Question 2 · Easy
In a healthy adult, active red marrow is found mainly in the:
1. ASmall bones of the hands and feet
2. BPelvis, sternum, vertebrae and ribs
3. CShafts of the long bones
4. DLiver and spleen
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Answer: B · Pelvis, sternum, vertebrae and ribs
At birth nearly all marrow is red, but during childhood the shafts of the long bones fill with fat and become yellow marrow. By adulthood, active red marrow is limited mainly to the flat bones of the axial skeleton (pelvis, sternum, vertebrae, ribs and skull) and the upper ends of the femur and humerus. This is why adult marrow biopsies are taken from the posterior iliac crest, with the sternum used for aspiration only. Yellow marrow can turn red again when demand rises, as in chronic hemolysis.
- A: The small bones of the hands and feet lose their active marrow early in childhood.
- C: The shafts of the long bones change to fatty yellow marrow during childhood.
- D: The liver and spleen make blood only in the fetus or in extramedullary hematopoiesis.
Question 3 · Medium
Plerixafor is given before apheresis to release hematopoietic stem cells from the marrow into the blood. Which receptor does it block?
1. AThe G-CSF receptor
2. BThe thrombopoietin receptor (c-Mpl)
3. CCXCR4, the receptor for CXCL12
4. DThe erythropoietin receptor
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Answer: C · CXCR4, the receptor for CXCL12
Stem cells are held in their marrow niche partly by the chemokine CXCL12 (stromal cell-derived factor-1), which binds the CXCR4 receptor on the stem cell. Plerixafor blocks CXCR4, so stem cells are released into the blood within hours and can be collected by apheresis. It is often combined with G-CSF, which mobilizes stem cells by a different route. Mobilization is monitored by counting CD34-positive cells in the blood by flow cytometry.
- A: G-CSF is itself given to mobilize stem cells; plerixafor does not block its receptor.
- B: Plerixafor does not act on c-Mpl; TPO receptor agonists such as romiplostim stimulate it.
- D: The erythropoietin receptor is on erythroid progenitors and does not hold stem cells in the niche.
Question 4 · Easy
The main cytokine that drives eosinophil production in the marrow is:
1. AInterleukin-5
2. BGranulocyte colony-stimulating factor
3. CMacrophage colony-stimulating factor
4. DInterleukin-7
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Answer: A · Interleukin-5
Interleukin-5, made mainly by Th2 helper T cells, stimulates the growth, maturation and survival of eosinophils. This is why eosinophil counts rise in allergic disease and helminth infection, which are Th2 responses. Antibodies that block IL-5 or its receptor are used to lower eosinophils in severe eosinophilic asthma. IL-3 and GM-CSF also support eosinophils, but less specifically.
- B: G-CSF drives neutrophil production.
- C: M-CSF drives monocyte and macrophage production.
- D: IL-7 supports the development of B and T lymphocytes.
Question 5 · Hard
A 4-month-old has had skin abscesses and pneumonia since birth. Every count shows an absolute neutrophil count of 0.1 × 10^9/L (lower limit for age about 1.0 × 10^9/L) with normal red cells and platelets. The marrow has normal numbers of myeloblasts and promyelocytes but almost no myelocytes, metamyelocytes, bands or neutrophils. These findings are best described as:
1. APeripheral destruction of mature neutrophils
2. BMaturation arrest at the promyelocyte stage
3. CNormal marrow with neutrophils held in tissues
4. DFailure of the stem cell in all lineages
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Answer: B · Maturation arrest at the promyelocyte stage
The early stages are present but the later ones are missing, so neutrophil production stops at the promyelocyte stage: a maturation arrest. This is the classic marrow picture of severe congenital neutropenia, most often caused by ELANE mutations, which presents in infancy with serious bacterial infections. When neutrophils are destroyed in the blood, the marrow instead shows all stages, often with increased later forms. Stem cell failure would also reduce red cell and platelet precursors.
- A: Peripheral destruction gives a marrow with all stages present, often increased.
- C: Neutrophils held in tissues would not remove the later stages from the marrow.
- D: Stem cell failure would also lower red cells and platelets and empty the marrow of early forms.
Question 6 · Easy
Most of a neutrophil's primary (azurophilic) granules are made during which maturation stage?
1. AMyelocyte
2. BMyeloblast
3. CMetamyelocyte
4. DPromyelocyte
Answer and explanation in LearnFree account
Question 7 · Medium
In the classic model of hematopoiesis, megakaryocytes share their closest committed progenitor with which cells?
1. AB lymphocytes
2. BErythroid precursors
3. CMonocytes
4. DT lymphocytes
Answer and explanation in LearnFree account
Question 8 · Easy
Which sequence shows neutrophil maturation in the correct order?
1. APromyelocyte, myeloblast, myelocyte, metamyelocyte, band
2. BMyeloblast, promyelocyte, myelocyte, metamyelocyte, band
3. CMyeloblast, promyelocyte, metamyelocyte, myelocyte, band
4. DMyeloblast, myelocyte, promyelocyte, metamyelocyte, band
Answer and explanation in LearnFree account
Question 9 · Medium
On a Wright-stained marrow film, the deep blue cytoplasm of a basophilic normoblast is due to:
1. ALarge amounts of hemoglobin
2. BMany ribosomes making globin
3. CStored iron in the cytoplasm
4. DNumerous primary granules
Answer and explanation in LearnFree account
Question 10 · Easy
Where are the first blood cells of the embryo formed, in about the third week after conception?
1. AThe spleen
2. BThe bone marrow
3. CThe fetal liver
4. DThe yolk sac
Answer and explanation in LearnFree account
Question 11 · Medium
Erythropoietin raises red cell output mainly by:
1. AKeeping erythroid progenitors from dying by apoptosis
2. BTurning myeloid progenitors into erythroid cells
3. CMaking mature red cells survive longer in the blood
4. DReleasing stored red cells from the spleen
Answer and explanation in LearnFree account
Question 12 · Easy
Which erythroid precursor loses its nucleus to become a reticulocyte?
1. APolychromatic normoblast
2. BBasophilic normoblast
3. COrthochromic normoblast
4. DPronormoblast
Answer and explanation in LearnFree account
Question 13 · Easy
Where do T lymphocytes, which arise from marrow progenitors, complete their maturation?
1. ABone marrow
2. BLymph nodes
3. CSpleen
4. DThymus
Answer and explanation in LearnFree account

Hematopoiesis and cell maturation

As blood cells mature in the marrow, which change in the nucleus is typical?

In a healthy adult, active red marrow is found mainly in the:

Plerixafor is given before apheresis to release hematopoietic stem cells from the marrow into the blood. Which receptor does it block?

The main cytokine that drives eosinophil production in the marrow is:

Most of a neutrophil's primary (azurophilic) granules are made during which maturation stage?

In the classic model of hematopoiesis, megakaryocytes share their closest committed progenitor with which cells?

Which sequence shows neutrophil maturation in the correct order?

On a Wright-stained marrow film, the deep blue cytoplasm of a basophilic normoblast is due to:

Where are the first blood cells of the embryo formed, in about the third week after conception?

Erythropoietin raises red cell output mainly by:

Which erythroid precursor loses its nucleus to become a reticulocyte?

Where do T lymphocytes, which arise from marrow progenitors, complete their maturation?