RBC Exam UPDATED ACTUAL Exam
Questions and CORRECT Answers
What is the first type of cell produced by the developing embryo?
A. Erythrocyte
B. Granulocyte
C. Lymphocyte
D. Thrombocyte - CORRECT ANSWER -A. Erythrocyte
The need for oxygen delivery to developing tissues results in the production of erythrocytes
before other blood cells. Erythropoiesis commences in the yolk sac as early as the fourteenth day
of embryonic development. These primitive red cells produce embryonic hemoglobins that
temporarily serve oxygen needs of the fetus. Myelopoietic and lymphopoietic activities beginw
ehn the liver and spleen become sites of production at 6-9 weeks of gestation; however,
erythropoiesis still predominates. At this time, the red cells produce hemoglobin F, which is the
chief oxygen carrier during fetal life.
What percentage of tissue located in the bone marrow cavities of adults is fat?
A. 10%
B. 25%
C. 50%
D. 75% - CORRECT ANSWER -C. 50%
In the infant, there is an increased demand for blood formation because of the rate of growth. At
birth, all bone marrow cavities are filled with hematopoietic tissue (active red marrow). As the
growth rate slows, there is less need for active marrow. Fatty infiltration of the marrow becomes
noticeable at about 4 years of age as cell production diminishes within the shafts of the long
bones and is filled with yellow inactive tissue. Fat comprises 50% of the total marrow space in
the adult. Except for lymphopoiesis, hematopoiesis is confined to the flat bones and pelvic area
by the age of 25 years.
Which of the following is not characteristic of pluripotent hematopoietic stem cells?
A. Possess self-renewal ability
,B. Produce progenitor cells committed to a single cell lineage
C. Express the stem cell marker CD13
D. Are morphologically unrecognizable - CORRECT ANSWER -C. Express the stem cell
marker CD13
Hematopoietic stem cells can make copies of themselves to maintain the stem cell pool and
possess the ability to generate cells of all lineages (pluripotential). These stem cells give rise to
multipotential myeloid and lymphoid progenitor cells, which ultimately produce progenitor cells
that are restricted to a specific cell lineage. With appropriate cytokine stimulus, the committed
progenitor cells undergo proliferation to recognizable precursors that produce an amplified
number of mature end-stage cells. Stem cells and progenitor cells cannot be morphologically
distinguished (look similar to small lymphocytes) but can be identified phenotypically by
markers such as the stem cell marker CD34. CD34 expression is lost as antigens for a specific
cell lineage are expressed. CD13 is a marker expressed by myeloid precursors.
As an adult, what are the two best areas for obtaining active bone marrow by aspiration?
A. Vertebra, tibia
B. Sternum, vertebra
C. Anteroir iliac crest, tibia
D. Posterior iliac crest, sternum - CORRECT ANSWER -D. Posterior iliac crest, sternum
Unlike the infant, in which all BM is capable of forming blood cells, the active marrow in an
adult is confined to the flat bones of the skeleton such as the sternum and posterior iliac crest.
Although the spinous processes of the vertebrae contain active marrow, these sites are rarely
used for aspiration in adults because of the danger of damage to the spinal cord. Sternal puncture
also presents a possibility of serious damage to underlying structures but may be used because of
easy accessibility or if the aspirate is a dry tap in the iliac crest. To obtain both a BM aspirate and
core biopsy, most marrow specimens are taken from the posterior iliac crest. The anterior iliac
crest may occasionally be used in adults and sometimes the tibia in children less than 2 years of
age.
What is the normal ratio of myeloid to erythroid precursors in bone marrow (M:E ratio)?
A. 1:1
B. 1:3
, C. 4:1
D. 8:1 - CORRECT ANSWER -C. 4:1
The ratio between all granulocytes and their precursors and all nucleated red cell precursors
represent the myeloid-to-erythroid ratio. Myeloid precursors outnumber erythroid precursors by
about 3 or 4 to 1 in the normal BM. Although there are many more RBCs in the peripheral blood
than granulocytes, RBCs have a much longer life span in circulation (120 days) as compared to
granulocytes (about 8 hours). Granulocytes, therefore, require a more continual production than
erythrocytes and are the most numerous marrow precursors. Alteration in the M:E ratio such as
1:1 or 8:1 may indicate erythroid hyperplasia or granulocytic hyperplasia, respectively.
Which of the following does not accurately describe hematopoietic growth factors?
A. Bind to target cell receptors to express activity
B. Action of majority is lineage restricted
C. May promote or suppress cell death
D. Can stimulate or inhibit cell proliferation - CORRECT ANSWER -B. Action of
majority is lineage restricted
A diverse group of growth factors (cytokines) regulate and maintain hematopoiesis in a steady
state. Most are not lineage restricted but can act on more than on cell type and have multiple
functions. IL-3 and colony stimulating factors (GM-CSF) affect multiple cell lines; whereas
erythropoietin action is limited to erythroid cells. Cytokines are glycoproteins that usually
express activity by binding to specific receptors on target cells. The action of growth factors on
hematopoietic progenitor and precursor cells can stimulate or inhibit cell proliferation and
differentiation as well as promote or suppress cell death. Growth factors may act alone or
together to exert a positive or negative influence on hematopoiesis as well as on the function of
mature cells. A determining factor for controlling the rate of cell production is cytokine
stimulation in response to physiological need.
In the third month of gestation, what is the primary site of hematopoiesis?
A. Liver
B. Marrow of long bones
C. Spleen
D. Yolk sac - CORRECT ANSWER -A. Liver
The liver of the fetus assumes responsibility for hematopoiesis about the second month of
gestation. From 3-6 months of fetal development the spleen, thymus, and lymph nodes are also
Questions and CORRECT Answers
What is the first type of cell produced by the developing embryo?
A. Erythrocyte
B. Granulocyte
C. Lymphocyte
D. Thrombocyte - CORRECT ANSWER -A. Erythrocyte
The need for oxygen delivery to developing tissues results in the production of erythrocytes
before other blood cells. Erythropoiesis commences in the yolk sac as early as the fourteenth day
of embryonic development. These primitive red cells produce embryonic hemoglobins that
temporarily serve oxygen needs of the fetus. Myelopoietic and lymphopoietic activities beginw
ehn the liver and spleen become sites of production at 6-9 weeks of gestation; however,
erythropoiesis still predominates. At this time, the red cells produce hemoglobin F, which is the
chief oxygen carrier during fetal life.
What percentage of tissue located in the bone marrow cavities of adults is fat?
A. 10%
B. 25%
C. 50%
D. 75% - CORRECT ANSWER -C. 50%
In the infant, there is an increased demand for blood formation because of the rate of growth. At
birth, all bone marrow cavities are filled with hematopoietic tissue (active red marrow). As the
growth rate slows, there is less need for active marrow. Fatty infiltration of the marrow becomes
noticeable at about 4 years of age as cell production diminishes within the shafts of the long
bones and is filled with yellow inactive tissue. Fat comprises 50% of the total marrow space in
the adult. Except for lymphopoiesis, hematopoiesis is confined to the flat bones and pelvic area
by the age of 25 years.
Which of the following is not characteristic of pluripotent hematopoietic stem cells?
A. Possess self-renewal ability
,B. Produce progenitor cells committed to a single cell lineage
C. Express the stem cell marker CD13
D. Are morphologically unrecognizable - CORRECT ANSWER -C. Express the stem cell
marker CD13
Hematopoietic stem cells can make copies of themselves to maintain the stem cell pool and
possess the ability to generate cells of all lineages (pluripotential). These stem cells give rise to
multipotential myeloid and lymphoid progenitor cells, which ultimately produce progenitor cells
that are restricted to a specific cell lineage. With appropriate cytokine stimulus, the committed
progenitor cells undergo proliferation to recognizable precursors that produce an amplified
number of mature end-stage cells. Stem cells and progenitor cells cannot be morphologically
distinguished (look similar to small lymphocytes) but can be identified phenotypically by
markers such as the stem cell marker CD34. CD34 expression is lost as antigens for a specific
cell lineage are expressed. CD13 is a marker expressed by myeloid precursors.
As an adult, what are the two best areas for obtaining active bone marrow by aspiration?
A. Vertebra, tibia
B. Sternum, vertebra
C. Anteroir iliac crest, tibia
D. Posterior iliac crest, sternum - CORRECT ANSWER -D. Posterior iliac crest, sternum
Unlike the infant, in which all BM is capable of forming blood cells, the active marrow in an
adult is confined to the flat bones of the skeleton such as the sternum and posterior iliac crest.
Although the spinous processes of the vertebrae contain active marrow, these sites are rarely
used for aspiration in adults because of the danger of damage to the spinal cord. Sternal puncture
also presents a possibility of serious damage to underlying structures but may be used because of
easy accessibility or if the aspirate is a dry tap in the iliac crest. To obtain both a BM aspirate and
core biopsy, most marrow specimens are taken from the posterior iliac crest. The anterior iliac
crest may occasionally be used in adults and sometimes the tibia in children less than 2 years of
age.
What is the normal ratio of myeloid to erythroid precursors in bone marrow (M:E ratio)?
A. 1:1
B. 1:3
, C. 4:1
D. 8:1 - CORRECT ANSWER -C. 4:1
The ratio between all granulocytes and their precursors and all nucleated red cell precursors
represent the myeloid-to-erythroid ratio. Myeloid precursors outnumber erythroid precursors by
about 3 or 4 to 1 in the normal BM. Although there are many more RBCs in the peripheral blood
than granulocytes, RBCs have a much longer life span in circulation (120 days) as compared to
granulocytes (about 8 hours). Granulocytes, therefore, require a more continual production than
erythrocytes and are the most numerous marrow precursors. Alteration in the M:E ratio such as
1:1 or 8:1 may indicate erythroid hyperplasia or granulocytic hyperplasia, respectively.
Which of the following does not accurately describe hematopoietic growth factors?
A. Bind to target cell receptors to express activity
B. Action of majority is lineage restricted
C. May promote or suppress cell death
D. Can stimulate or inhibit cell proliferation - CORRECT ANSWER -B. Action of
majority is lineage restricted
A diverse group of growth factors (cytokines) regulate and maintain hematopoiesis in a steady
state. Most are not lineage restricted but can act on more than on cell type and have multiple
functions. IL-3 and colony stimulating factors (GM-CSF) affect multiple cell lines; whereas
erythropoietin action is limited to erythroid cells. Cytokines are glycoproteins that usually
express activity by binding to specific receptors on target cells. The action of growth factors on
hematopoietic progenitor and precursor cells can stimulate or inhibit cell proliferation and
differentiation as well as promote or suppress cell death. Growth factors may act alone or
together to exert a positive or negative influence on hematopoiesis as well as on the function of
mature cells. A determining factor for controlling the rate of cell production is cytokine
stimulation in response to physiological need.
In the third month of gestation, what is the primary site of hematopoiesis?
A. Liver
B. Marrow of long bones
C. Spleen
D. Yolk sac - CORRECT ANSWER -A. Liver
The liver of the fetus assumes responsibility for hematopoiesis about the second month of
gestation. From 3-6 months of fetal development the spleen, thymus, and lymph nodes are also
