hematopoiesis.pdf

Functions of Blood Respiratory Nutritional Excretory Buffering Action Maintenance of constant body temperature Transportation of hormones and other endocrine secretions that regulate cell function Body defense mechanism Red Blood Cells Platelets Basic Hematology Terminology H...

Functions of Blood Respiratory Nutritional Excretory Buffering Action Maintenance of constant body temperature Transportation of hormones and other endocrine secretions that regulate cell function Body defense mechanism Red Blood Cells Platelets Basic Hematology Terminology HEMATOPOIESIS Objectives: Explain the origin of blood cells Name at least three growth factors Name the cells in developmental order that will mature into erythrocytes, plasma cells, and the five leukocyte types.  Hematopoiesis Process of blood cell production, differentiation, and development. HEMATOPOIESIS Formation , development and specialization of all functional blood cells that are released from the bone marrow to the circulation Hematopoiesis Theory A. Monophyletic Theory - suggests that all blood cells are derived from a single progenitor stem cell called pluripotential stem cell B. Polyphyletic Theory - suggests that each blood cell lineages is derived from its own unique stem cell Stem Cell They are capable of self-renewal They give rise to differentiated progeny They are capable to reconstitute the hematopoietic system of a lethally irradiated host  Types of Human Stem Cells 1. Totipotential stem Cells - present in the first few hours after an ovum is fertilized - most versatile type of stem cell 2. Pluripotential stem cells - present several days after fertilization 3. Multipotential stem cells - derived from pluripotent stem cells  Mesoblastic / Hepatic Medullary / Myeloid Megaloblastic Start 19 to 20 days gestation 4th to 5th week of 5th month of gestation gestation End 8th – 12th week of 1 – 2 weeks after birth Lifetime gestation Site of hematopoiesis Yolk sac Liver Bone Marrow Hemoglobin Gower I, II, Portland Hgb F Hgb A1, A2, F Hematopoietic Tissue A. Bone Marrow - primary site of hematopoiesis at birth and throughout life - normal adult bone marrow has approximately equal amounts of red and yellow marrow Types of Marrow Red Marrow a. Haematopoietically active marrow b. In adults, it can be found in the : sternum, skull, scapulae, vertebrae, ribs, pelvic bone, proximal ends of the long bones Yellow Marrow a. Haematopoietically inactive marrow b. composed of adipocyte or fat cells Liver - main site of hematopoiesis during the hepatic phase - main site of production of Thrombopoietin -protein synthesis and degradation, coagulation factor synthesis, carbohydrate and lipid metabolism, drug and toxin clearance, iron recycling and storage, and hemoglobin degradation Spleen - largest lymphoid organ Functions: Filters the circulating blood (350mL) Stores 1/3 of platelet Methods : Pitting Culling Lymph nodes Functions: Play a role in the formation of new lymphocytes from the germinal centers Involved in the processing of specific immunoglobulins Filter particulate matter, debris and bacteria entering the lymph node via the lymph Thymus - maturation site of T-lymphocyte Cytokines and Growth Factors a group of specific glycoproteins that regulates the proliferation, differentiation, and maturation of hematopoietic precursor cells responsible for the stimulation or inhibition of production, differentiation, and trafficking of mature blood cells and their precursor Interleukins 1. They are proteins that exhibit multiple biologic activities, such as the regulation of autoimmune and inflammatory reactions and hematopoiesis. 2. They have synergistic interactions with other cytokines and growth factors. 3. They are part of interacting systems with amplification potential. 4. They are effective at very low concentrations. Examination of Maturing Blood Cells