GENERAL HISTOLOGY

Detailed explanation-1: -Inside the bone marrow, blood stem cells divide and mature to make new blood cells. During this process, the cells become either lymphocytes (a kind of white blood cell) or other blood-forming cells.

Detailed explanation-2: -B-cells and T-cells are the two main types of lymphocytes. There are primary and secondary organs involved in the complex development of lymphocytes, but in most cases, B-and T-lymphocytes are generated in bone marrow and in the thymus.

Detailed explanation-3: -Normally, hematopoietic stem cells within the bone marrow mature into a common lymphoid progenitor cell, which then becomes either a B-cell or a T cell. To become a B cell, it has to develop into an immature B-cell in the bone marrow and then complete its maturation in the spleen.

Detailed explanation-4: -In most mammals, including humans and mice, B cells develop from stem cells in the hemopoietic tissues themselves (Figure 24-6). Because they are sites where lymphocytes develop from precursor cells, the thymus and hemopoietic tissues are referred to as central (primary) lymphoid organs (see Figure 24-3).