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