hematopoeisis

• What are the primary functions of blood?

  Respiratory, nutritional, excretory, buffering action, maintenance of constant body temperature, transportation of hormones, and body defense mechanism
• How does blood contribute to the maintenance of body temperature?

  By regulating heat distribution throughout the body
• What are the two main types of blood cells mentioned?


  Red blood cells and platelets
• What is hematopoiesis?


  • Process of blood cell production
  • Differentiation and development of blood cells
  • Occurs in the bone marrow
• What is the significance of growth factors in hematopoiesis?

  They regulate the proliferation and differentiation of blood cells
• What are the two theories of hematopoiesis?

  Monophyletic Theory and Polyphyletic Theory
• What does the Monophyletic Theory suggest about blood cells?

  All blood cells are derived from a single progenitor stem cell
• What does the Polyphyletic Theory propose about blood cell lineages?

  Each blood cell lineage is derived from its own unique stem cell
• What are the characteristics of stem cells?

  They are capable of self-renewal, give rise to differentiated progeny, and can reconstitute the hematopoietic system
• What are the types of human stem cells?

  1. Totipotential stem cells

  • Present shortly after fertilization
  • Most versatile type

  1. Pluripotential stem cells

  • Present several days after fertilization

  1. Multipotential stem cells

  • Derived from pluripotent stem cells
• What is the primary site of hematopoiesis at birth and throughout life?

  Bone marrow
• What is the difference between red marrow and yellow marrow?

  Red marrow is hematopoietically active, while yellow marrow is inactive and composed of fat cells
• What is the main function of the liver in hematopoiesis?

  Main site of hematopoiesis during the hepatic phase and production of thrombopoietin
• What are the functions of the spleen?

  Filters circulating blood and stores 1/3 of platelets
• What are the functions of lymph nodes?

  • Formation of new lymphocytes from germinal centers
  • Processing of specific immunoglobulins
  • Filtering particulate matter, debris, and bacteria from lymph
• What is the maturation site of T-lymphocytes?

  Thymus
• What are cytokines and growth factors?

  • Specific glycoproteins that regulate hematopoietic precursor cells
  • Stimulate or inhibit production, differentiation, and trafficking of blood cells
• What are interleukins and their functions?


  Proteins that regulate autoimmune reactions, inflammatory reactions, and hematopoiesis
• How do interleukins interact with other cytokines and growth factors?

  They have synergistic interactions and are part of systems with amplification potential
• Why are interleukins effective at very low concentrations?

  Because they exhibit multiple biological activities
• What is the significance of examining maturing blood cells?

  • Understanding the development of blood cells
  • Identifying abnormalities in blood cell maturation