Hematopoiesis Formation and Development
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Questions and Answers

What is the result of mutations in the genes for the hemoglobin protein?

  • Thalassemia trait
  • Hemoglobin deficiency
  • Hemoglobin variants
  • Hemoglobinopathies (correct)

    • What is the normal range of hematocrit value for males?

  • 40-50%
  • 36-46%
  • 45-55%
  • 37-49% (correct)

    • What is the function of Mean Corpuscular Volume (MCV)?

  • To measure the portion of blood composed of erythrocytes
  • To measure the average size or volume of the RBC (correct)
  • To measure the weight of Hb in the average red cell
  • To measure the number of reticulocytes

    • What is the normal lifespan of RBCs?

    <p>100-120 days</p> Signup and view all the answers

    What is the characteristic of reticulocytes?

    <p>No nucleus, reticulum of RNA, and light blue staining</p> Signup and view all the answers

    What is the normal range of MCV?

    <p>70-100 fl</p> Signup and view all the answers

    What is the formula for calculating MCV?

    <p>Hct X 10/RBC Count in microliter</p> Signup and view all the answers

    What does MCH indicate?

    <p>The weight of Hb in the average red cell</p> Signup and view all the answers

    What does MCHC measure?

    <p>The concentration of Hb in the average red cell</p> Signup and view all the answers

    What is the normal value of MCHC?

    <p>32-36%</p> Signup and view all the answers

    Where does hematopoiesis occur in the third stage of intrauterine development?

    <p>Bone marrow</p> Signup and view all the answers

    What is the main component of the hemoglobin molecule?

    <p>Polypeptide chains</p> Signup and view all the answers

    What is anemia defined as?

    <p>A reduction in red blood cell mass or blood hemoglobin concentration</p> Signup and view all the answers

    During childhood, what replaces hematopoietic tissues in the long bones?

    <p>Fatty tissues</p> Signup and view all the answers

    What is the manifestation of anemia attributed to?

    <p>Tissue hypoxia</p> Signup and view all the answers

    How much oxygen binds to 1 gm of Hb?

    <p>1.39 ml O2</p> Signup and view all the answers

    What is the predominant type of hemoglobin in the fetus?

    <p>Hemoglobin F</p> Signup and view all the answers

    What is one of the compensatory mechanisms to increase oxygen delivery?

    <p>Increase in blood flow</p> Signup and view all the answers

    Where is red marrow concentrated in older children and adults?

    <p>Skull, vertebrae, pelvis, ribs, clavicles, sternum, and scapula</p> Signup and view all the answers

    What is the percentage of Hemoglobin A at birth?

    <p>30%</p> Signup and view all the answers

    What happens when the Hb level is less than 7 gm/dL?

    <p>Clinical findings of tachycardia and increased capillary pulsation</p> Signup and view all the answers

    When does the δ chain synthesis begin?

    <p>Late in the third trimester</p> Signup and view all the answers

    What stimulates the differentiation and clonal maturation of erythroid precursors into mature erythrocytes?

    <p>Erythropoietin</p> Signup and view all the answers

    What is the percentage of Hemoglobin F at 6-12 months of age?

    <p>Less than 2%</p> Signup and view all the answers

    What is the main function of vitamin C in iron absorption?

    <p>Converting ferric to ferrous iron</p> Signup and view all the answers

    Where is iron mainly absorbed in the body?

    <p>Duodenum and proximal jejunum</p> Signup and view all the answers

    What increases iron absorption in the body?

    <p>Both A and B</p> Signup and view all the answers

    What is a common manifestation of iron deficiency anemia?

    <p>Pallor</p> Signup and view all the answers

    What diet can decrease iron absorption?

    <p>Rich in phosphorus</p> Signup and view all the answers

    What is a risk factor for iron deficiency anemia in neonates?

    <p>All of the above</p> Signup and view all the answers

    What is a potential cause of chronic blood loss in infants and children?

    <p>All of the above</p> Signup and view all the answers

    What is a potential symptom of iron deficiency anemia?

    <p>All of the above</p> Signup and view all the answers

    What is the daily requirement of iron in mg/day?

    <p>8-15</p> Signup and view all the answers

    Which type of anemia is characterized by MCV of 100fl and MCHC of 32-34?

    <p>Normocytic normochromic</p> Signup and view all the answers

    Which of the following is an example of extracorpuscular defect leading to anemia?

    <p>Immune mechanism</p> Signup and view all the answers

    What is the primary cause of anemia due to inadequate production of RBCs or HB?

    <p>Decrease in the number of RBC precursors in the bone marrow</p> Signup and view all the answers

    Which of the following is an example of a microcytic hypochromic anemia?

    <p>Iron deficiency anemia</p> Signup and view all the answers

    What is the cause of anemia in chronic renal disease?

    <p>Decrease production despite the normal number of RBC precursors</p> Signup and view all the answers

    Which of the following is an example of an intrinsic defect leading to anemia?

    <p>Membrane defect</p> Signup and view all the answers

    What is the cause of anemia in pancytopenia?

    <p>Decrease in the number of RBC precursors in the bone marrow</p> Signup and view all the answers

    Study Notes

    Hematopoiesis

    • Hematopoiesis is the process of production of all types of blood cells, including formation, development, and differentiation of blood cells
    • Prenatally, hematopoiesis occurs in three stages:
      • Yolk sac hematopoiesis (1st 8 weeks)
      • Visceral hematopoiesis (8th week to 6th month)
      • Myeloid hematopoiesis (6th month onwards)

    Hemoglobin

    • Hemoglobin molecule is a tetramer made up of 2 pairs of polypeptide chains
    • Each chain has a heme group
    • Polypeptide chains differ from each other in both the number and sequence of amino acids
    • Synthesis is directed by separate genes

    Types of Hemoglobin in Humans

    • In the embryo (4-8 weeks gestation):
      • Gower 1 (ζ2ε2)
      • Gower 2 (α2ε2)
      • Hemoglobin Portland (ζ2γ2)
    • In the fetus:
      • Hemoglobin F (α2γ2) predominates during fetal life
      • Represents 70% of total Hb at birth
      • Decreases to less than 2% after 6-12 months of age
    • In adults:
      • Hemoglobin A (α2β2)
      • Hemoglobin A2 (α2δ2)

    Genetics

    • Mutations in the genes for the hemoglobin protein result in hemoglobin variants
    • Some mutant forms of hemoglobin cause a group of hereditary diseases termed hemoglobinopathies

    Role in Disease

    • Hemoglobin deficiency can be caused by:
      • Decreased amount of hemoglobin molecules
      • Decreased ability of each molecule to bind oxygen at the same partial pressure of oxygen
    • Hemoglobinopathies may cause both

    Blood Indices

    • Normal RBCs:
      • No nucleus
      • Biconcave discs
      • Center 1/3 pallor
      • Pink cytoplasm (Hb filled)
      • Cell size 7-8 µ
      • 100-120 days life span
    • Reticulocyte (young RBCs):
      • No definite nucleus
      • Reticulum of RNA
      • Deep blue staining
      • Light blue cytoplasm
      • Cell size about 10 µ

    Hematocrit Value (HCT)

    • Portion of 100 blood composed of erythrocytes
    • Normal males: 37-49%
    • Normal females: 36-46%

    Mean Corpuscular Volume (MCV)

    • Reflects the average size or volume of the RBC
    • Expressed in femtoliters (fl)
    • Calculated as: MCV = Volume of packed red cells in 1000 ml blood (Hct X 10) / RBC Count (Red cell count) in million in microliter
    • Normal value: 70-100 fl

    Mean Cell Hemoglobin (MCH)

    • Indicates the weight of Hb in the average red cell

    Mean Cell Hemoglobin Concentration (MCHC)

    • Indicates the concentration of Hb in the average red cell or the ratio of the weight of Hb to the volume in which it is contained
    • Expressed in percent
    • Normal value: 32-36%

    Anemia

    • Defined as a reduction in red blood cell mass or blood hemoglobin concentration either singly or in combination
    • Compensatory mechanisms:
      • Increase in blood flow
      • Increase in red cell mass
      • Increase oxygen unloading

    Classification of Anemia

    • Etiological classification:
      • A- Inadequate production of RBCs or HB
      • B- Anemia due to excessive destruction of RBCs
      • C- Anemia due to excessive blood loss
    • Morphological classification:
      • A- Normocytic normochromic
      • B- Microcytic hypochromic
      • C- Macrocytic normochromic anemia

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    Description

    Learn about the process of hematopoiesis, including the formation, development, and differentiation of blood cells. Explore the stages of hematopoiesis, from the yolk sac to the bone marrow.

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