Through the process of hemopoiesis, the formed elements of blood are continually produced, replacing the relatively short-lived erythrocytes, leukocytes, and platelets. Hemopoiesis begins in the red bone marrow, with hemopoietic stem cells that differentiate into myeloid and lymphoid lineages. Myeloid stem cells give rise to most of the formed elements. Lymphoid stem cells give rise only to the various lymphocytes designated as B and T cells, and NK cells. Hemopoietic growth factors, including erythropoietin, thrombopoietin, colony-stimulating factors, and interleukins, promote the proliferation and differentiation of formed elements.
bone marrow biopsy
diagnostic test of a sample of red bone marrow
bone marrow transplant
treatment in which a donor’s healthy bone marrow with its stem cells replaces diseased or damaged bone marrow of a patient
colony-stimulating factors (CSFs)
glycoproteins that trigger the proliferation and differentiation of myeloblasts into granular leukocytes (basophils, neutrophils, and eosinophils)
cytokines
class of proteins that act as autocrine or paracrine signaling molecules; in the cardiovascular system, they stimulate the proliferation of progenitor cells and help to stimulate both nonspecific and specific resistance to disease
erythropoietin (EPO)
glycoprotein that triggers the bone marrow to produce RBCs; secreted by the kidney in response to low oxygen levels
hemocytoblast
hemopoietic stem cell that gives rise to the formed elements of blood
hemopoiesis
production of the formed elements of blood
hemopoietic growth factors
chemical signals including erythropoietin, thrombopoietin, colony-stimulating factors, and interleukins that regulate the differentiation and proliferation of particular blood progenitor cells
hemopoietic stem cell
type of pluripotent stem cell that gives rise to the formed elements of blood (hemocytoblast)
interleukins
signaling molecules that may function in hemopoiesis, inflammation, and specific immune responses
lymphoid stem cells
type of hemopoietic stem cells that gives rise to lymphocytes, including various T cells, B cells, and NK cells, all of which function in immunity
myeloid stem cells
type of hemopoietic stem cell that gives rise to some formed elements, including erythrocytes, megakaryocytes that produce platelets, and a myeloblast lineage that gives rise to monocytes and three forms of granular leukocytes (neutrophils, eosinophils, and basophils)
pluripotent stem cell
stem cell that derives from totipotent stem cells and is capable of differentiating into many, but not all, cell types
totipotent stem cell
embryonic stem cell that is capable of differentiating into any and all cells of the body; enabling the full development of an organism
thrombopoietin
hormone secreted by the liver and kidneys that prompts the development of megakaryocytes into thrombocytes (platelets)
Watch this video to see doctors discuss the dangers of blood doping in sports. What are the some potential side effects of blood doping?
Side effects can include heart disease, stroke, pulmonary embolism, and virus transmission.
1. Which of the formed elements arise from myeloid stem cells?
A) B cells
B) natural killer cells
C) platelets
D) all of the above
C
2. Which of the following statements about erythropoietin is true?
A) It facilitates the proliferation and differentiation of the erythrocyte lineage.
B) It is a hormone produced by the thyroid gland.
C) It is a hemopoietic growth factor that prompts lymphoid stem cells to leave the bone marrow.
D) Both a and b are true.
A
3. Interleukins are associated primarily with which of the following?
A) production of various lymphocytes
B) immune responses
C) inflammation
D) all of the above
D
1. Myelofibrosis is a disorder in which inflammation and scar tissue formation in the bone marrow impair hemopoiesis. One sign is an enlarged spleen. Why?
When disease impairs the ability of the bone marrow to participate in hemopoiesis, extramedullary hemopoiesis begins in the patient’s liver and spleen. This causes the spleen to enlarge.
2. Would you expect a patient with a form of cancer called acute myelogenous leukemia to experience impaired production of erythrocytes, or impaired production of lymphocytes? Explain your choice.
The adjective myelogenous suggests a condition originating from (generated by) myeloid cells. Acute myelogenous leukemia impairs the production of erythrocytes and other mature formed elements of the myeloid stem cell lineage. Lymphocytes arise from the lymphoid stem cell line.