Chapter 4

1. Projection of calcified bone extending from cortical bone into the marrow space; provides support for marrow cells
4. The region at the interface between the non-lymphoid red pulp and the lymphoid white-pulp of the spleen (Two words)
6. Protein produced by many cell types; it modulates the function of other cell types
9. Cell involved in resorption and remodeling of calcified bone
12. Formation and development of white blood cells
14. Formation and maturation of erythrocytes in the bone marrow
16. A parenchymatous tissue of the spleen that consists of loose plates or cords infiltrated with red blood cells (Two words)
17. Flat cells that line the cavities of the blood and lymphatic vessels, heart, and other related body cavities
18. Production and development of blood cells normally occurring in the bone marrow
19. Yolk sac phase of hematopoiesis
22. Cell whose cytoplasm is largely replaced with a single fat vacuole
23. An abdominal organ involved in the production and removal of blood cells in most vertebrates and forming part of the immune system
26. A phagocytic cell which forms the lining of the sinusoids of the liver and is involved in the breakdown of red blood cells
27. The site of the second phase of fetal hematopoiesis
28. Extensive splenic damage secondary to infarction; often seen in older children and adults with sickle cell anemia

2. A soft fatty substance in the cavities of bones, in which blood cells are produced (Two words)
3. A family of polypeptide products (proteins) produced by many cell types that are involved in lymphocyte recruitment, lymphocyte proliferation, and cellular responses in immunology
5. Removal of the spleen
7. Cell involved in formation of calcified bone
8. The development of megakaryocytes
10. Disorder characterized by enlargement of the spleen and pancytopenia in the presence of a hyperactive bone marrow
11. A parenchymatous tissue of the spleen that consists of compact masses of lymphatic cells (Two words)
13. Hormone secreted by the kidney that regulates erythrocyte production by stimulating the stem cells of the bone marrow to mature into erythrocytes
15. Abnormal enlargement of the spleen
20. A lymphoid organ situated in the neck of vertebrates that produces T cells for the immune system
21. Bone marrow not involved in the production of blood cells
23. Cellular element of the hematopoietic microenvironment in the red portion of bone marrow
24. A colorless fluid containing white blood cells, which bathes the tissues and drains through the lymphatic system into the bloodstream
25. Bone marrow characterized by meshes of the reticular network that contain the developmental stages of red blood cells, white blood cells, and megakaryocytes