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Introduction to Blood and Hematopoiesis
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Which of the following is not true of the spleen in normal individuals?
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A. It serves as a filter for the blood.
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B. It is an important source of immunoglobulins.
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C. It is enlarged in many conditions associated with acute or chronic activation of the immune system.
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D. It is an important source of formed blood elements.
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E. It is a rare site of primary tumor development.
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In normal humans, the spleen is primarily a lymphoid and macrophage organ and contains a paucity of hematopoietic and progenitor and precursor cells. (The answer is D.)
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Which of the following is not true of lymph nodes?
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A. They filter the lymph.
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B. They contain mainly B cells and few T cells.
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C. They may become painfully enlarged in acute immune reactions.
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D. They are a source of immunoglobulins.
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E. They contain numerous antigen-presenting cells.
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Lymph nodes contain B lymphocytes concentrated within follicles called germinal centers. Between these germinal centers and within the central part of the node the predominant cells are T lymphocytes. (The answer is B.)
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Which of the following is not true of the bone marrow?
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A. It serves as the major source of formed blood elements after birth.
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B. In patients who are suspected of having metastatic carcinoma, examination of the marrow may be useful in establishing a tissue diagnosis.
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C. It is often examined to determine the cause of pancytopenia.
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D. It is the primary site of hematopoiesis during embryonic development.
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E. It contains fat cells that may negatively regulate hematopoiesis.
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F. It contains a niche that nurtures stem cells.
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During embryonic development, the primary sites of hematopoiesis are the yolk sac, the mesonephros, and the liver. (The answer is D.)
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Which of the following is not true of hematopoietic growth factors?
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A. Thrombopoietin production increases in response to thrombocytopenia.
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B. Erythropoietin production increases in response to blood loss.
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