hematopoiesis

Lesson 2: Hematopoiesis

  1. Define the function of the following cellular components:

  1. Chromatin

    1. DNA

  2. Euchromatin

    1. active DNA

  3. Heterochromatin

    1. inactive DNA

  4. Endoplasmic reticulum

    1. protein modification

  5. Golgi apparatus

    1. modification and packaging for export

  6. Lysosome

    1. digestive organelle

  7. Microfilaments

    1. fine actin filaments involved in muscle contractions

    2. form cytoskeleton, cilia, and flagella

  8. Microtubules

    1. support cell and give shape

    2. intracellular and cellular movement, form centrioles

  9. Mitochondria

    1. provide ATP

    2. ox phos

  10. Nuclear envelope

    1. separate nucleus from other parts of cell

  11. Nucleolus

    1. site of ribosome subunit manufacturing

  12. Nucleus

    1. houses DNA and nucleoli

  13. Plasma membrane

    1. contain contents of cell

  1. Describe the structure of the cell membrane.

    1. lipid bilayer w/ proteins embedded or displayed

  2. Illustrate the stages of the cell cycle.

    1. Identify each phase of mitosis and describe the chromosomal arrangement in each phase.

  1. Define the following terms:

  1. Hematopoiesis

    1. regulated process of production, development, differentiation, and maturation of circulating blood cells

  2. Differentiation

    1. process for providing diverse cell populations needed for specialized function

  3. Commitment

    1. point in which a cell must differentiate into a specific line

  4. Maturation

    1. cell is fully developed and has all characteristics

  1. Define and identify characteristics of hematopoietic stem cells.

    1. Describe a progenitor cell.

      1. between stem cell and precursor cells

      2. limited self renewal, not morphologically identifiable, can form colonies of cells

    2. Explain pluripotent hematopoietic stem cells.

      1. can form any blood cell

  2. Diagram and correctly differentiate cells in the hematopoietic stem cell model.

  3. Define cytokines/growth factors.

    1. cytokines: chemical signals that direct the cell activity thru signaling

    2. growth factors: another name for proliferative cytokines, a type of cytokine

      1. promote cell survival, proliferation, regulate differentiation, not lineage specific

    3. List where cytokines are produced.

      1. bone marrow or hematopoietic microenvironment by stromal cells

      2. erythropoietin in kidneys, transported to marrow

  4. Explain apoptosis.

    1. programmed cell death, cell is signaled to die so it dies

  5. Define the following terms and list the major growth factors/cytokines involved in each:

  1. Erythropoiesis

    1. formation of RBCs in marrow.

      1. progenitor cells (CFU-GEMM) give rise to BFU-e (bust forming units) and form after about 14 days. BFU-E to CFU-E that can give rise to erythrocyte progenitors

    2. erythropoietin is the primary GF

    3. myeloid stem cell → pronormoblast → basophilic normoblast → polychromatophilic normoblast → orthochromic normoblast → polychromatic erythrocyte → erythrocyte

  2. Granulopoiesis

    1. formation of granulocytes (neutrophil, eosinophil, basophil)

    2. derived from CFU-GEMM and CFU-GM

    3. G-CSF promotes granulocyte differentiation

    4. IL-3 is GF

    5. basophil diff:

      1. myeloid → myeloblast → promyelocyte → immature basophil → basophil

    6. eosinophil diff:

      1. myeloid → myeloblast → promyelocyte → immature eosinophil → eosinophil

    7. neutrophil diff:

      1. myeloid → myeloblast → promyelocyte → myelocyte → metamyelocyte → band neutrophil → segmented neutrophil

  3. Monopoiesis

    1. formation of monocytes

    2. derived from CFU-GEMM and CFU-GM

    3. M-CSF promotes monocyte differentiation

    4. IL-3 is GF

    5. monocyte diff: 

      1. myeloid → immature monocyte → monocyte → macrophage

  4. Megakaryopoiesis

    1. formation of platelets in marrow

      1. CFU-GEMM → CFU-Mk (megakaryocyte proliferator)

    2. IL-11 and thrombopoietin regulate platelet production

    3. platelet diff

      1. myeloid → megakaryocyte → platelets

  5. Lymphopoiesis

    1. formation of lymphocytes

      1. in marrow, thymus, lymph nodes, spleen

    2. many growth factors (different for different types of T cells/B cells)

    3. B cell diff:

      1. lymphoid → pre-B → b lymphoblast → b cell → plasma cell

    4. T cell diff:

      1. lymphoid → pre T → t lymphoblast → T cell

  1. Discuss the importance of erythropoietin, IL-3, and thrombopoietin in hematopoiesis.

    1. needed for maturation into particular cell types

      1. erythropoietin = RBCs

      2. IL-3 = granulocytes and monocytes

      3. thrombopoietin = platelets (also IL-11)

  2. Explain how growth factors inhibit cellular proliferation.

    1. NOT GROWTH FACTORS JUST INHIBITORY CYTOKINES I HATE THIS USE OF TERMINOLOGY

    2. decrease stimulating GF production

    3. increase inhibitory factors

  3. Describe the components of the hematopoietic microenvironment and their function.

    1. cellular: made of stromal cells

      1. adipose tissue, endothelial cells, fibroblasts, T cells, macrophages

      2. produce growth factors and components of ECM

    2. ECM:

      1. made of collagen, glycoproteins, and glycosaminoglycans

      2. provides structural support, plays a role in progenitor cells to stroma binding, helps cell-cell interactions, binds and localizes cytokines