X Her brotherâs illness forced her to explore feelings that had lied dormant for some time. â â¦. that had lain dormantâ¦ [past perfect of lie (1)]. X I laid down on my bed and went to sleep. â I lay down on my bedâ¦ [simple past of lie (1)]. X Sheâs laying flat on her back, out for the count. â Sheâs lying flat on her backâ¦ [present continuous of lie (1)]. X When she died, she was lain in an ornate wooden coffin. â â¦she was laid in an ornate wooden coffin.
The receptors match only one specific antigen. White blood cells called lymphocytes originate in the bone marrow but migrate to parts of the lymphatic system such as the lymph nodes, spleen, and thymus. There are two main types of lymphatic cells, T cells and B cells.he receptors match only one specific antigen. White blood cells called lymphocytes originate in the bone marrow but migrate to parts of the lymphatic system such as the lymph nodes, spleen, and thymus. There are two main types of lymphatic cells, T cells and B cells.
The immune system is a system of many biological structures and processes within an organism that protects against disease. To function properly, an immune system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue. cells and T cells are the major types of lymphocytes and are derived from hematopoietic stem cells in the bone marrow. B cells are involved in the humoral immune response, whereas T cells are involved in cell-mediated immune response.