MEDRADSC 2X03 Lecture Notes - Lecture 11: Bone Marrow, Stem Cell, Haematopoiesis

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 2X03
• Professor: Sandra Charbonneau

Document Summary

Hematopoietic system structure: stem cell tissues located primarily in red bone marrow of flat bones, spine and proximal femur, humerus (in adult, very small number of stem cells in circulating blood (all the rest in bone) Liver and spleen are normally dormant for hematopoiesis but can be stimulated to produce: liver not normally actively dividing, but could. Precursor cells: form immature cells, erythroblasts - rbc"s, myeloblasts - immature bone marrow cells, megakaryoblasts - large bone marrow cells, monoblasts - gives rise to monocytes ->large leukocyte, lymphoblasts - wbc"s, these multiply and differentiate into mature cells. Located in tonsils, lymph nodes, spleen, thymus: produces lymphocytes, tissues are very radiosensitive, largely due to apoptosis, depleted of cells by small doses. Response of stem cells to radiation: primary effect on bone marrow, reduced number of stem cells, very little repair, very radiosensitive! (d0< 1gy)