Erythrocyte Production and Destruction Flashcards

1
Q
  1. Which of the following is an erythrocyte progenitor?
    a. Pronormoblast
    b. Reticulocyte
    c. CFU-E
    d. Orthochromic normoblast
A

c. CFU-E

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2
Q
  1. Which of the following is the most mature normoblast?
    a. Orthochromic normoblast
    b. Basophilic normoblast
    c. Pronormoblast
    d. Polychromatic normoblast
A

a. Orthochromic normoblast

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3
Q
  1. What erythroid precursor can be described as follows: the
    cell is of medium size compared with other normoblasts,
    with an N:C ratio of nearly 1:1. The nuclear chromatin is
    condensed and chunky throughout the nucleus. No nucleoli are seen. The cytoplasm is a muddy, blue-pink
    color.
    a. Reticulocyte
    b. Pronormoblast
    c. Orthochromic normoblast
    d. Polychromatic normoblast
A

d. Polychromatic normoblast

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4
Q
  1. Which of the following is not related to the effects of erythropoietin?
    a. The number of divisions of a normoblast
    b. The formation of pores in sinusoidal endothelial cells
    for marrow egress
    c. The time between mitoses of normoblasts
    d. The production of antiapoptotic molecules by erythroid
    progenitors
A

b. The formation of pores in sinusoidal endothelial cells
for marrow egress

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5
Q
  1. Hypoxia stimulates RBC production by:
    a. Inducing more pluripotent stem cells into the erythroid
    lineage
    b. Stimulating EPO production by the kidney
    c. Increasing the number of RBC mitoses
    d. Stimulating the production of fibronectin by macrophages of the bone marrow
A

b. Stimulating EPO production by the kidney

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6
Q
  1. In the bone marrow, RBC precursors are located:
    a. In the center of the hematopoietic cords
    b. Adjacent to megakaryocytes along the adventitial cell
    lining
    c. Surrounding fat cells in apoptotic islands
    d. Surrounding macrophages in erythroid islands
A

d. Surrounding macrophages in erythroid islands

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7
Q
  1. Which of the following determines the timing of egress of
    RBCs from the bone marrow?
    a. Maturing normoblasts slowly lose receptors for adhesive molecules that bind them to stromal cells.
    b. Stromal cells decrease production of adhesive molecules over time as RBCs mature.
    c. Endothelial cells of the venous sinus form pores at
    specified intervals of time, allowing egress of free cells.
    d. Periodic apoptosis of pronormoblasts in the marrow
    cords occurs.
A

a. Maturing normoblasts slowly lose receptors for adhesive molecules that bind them to stromal cells.

Egress : action of leaving; exiting

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8
Q
  1. What single feature of normal RBCs is most responsible for
    limiting their life span?
    a. Loss of mitochondria
    b. Increased flexibility of the cell membrane
    c. Reduction of hemoglobin iron
    d. Loss of the nucleus
A

d. Loss of the nucleus

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9
Q
  1. Intravascular or fragmentation hemolysis is the result of
    trauma to RBCs while in the circulation.
    a. True
    b. False
A

a. True

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10
Q
  1. Extravascular hemolysis occurs when:
    a. RBCs are mechanically ruptured
    b. RBCs extravasate from the blood vessels into the tissues
    c. Splenic macrophages ingest senescent cells
    d. Erythrocytes are trapped in blood clots outside the blood vessels
A

c. Splenic macrophages ingest senescent cells

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11
Q
  1. A pronormoblast in its usual location belongs to the RBC
    mass of the body, but not to the erythron.
    a. True
    b. False
A

b. False

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12
Q
  1. A cell has an N:C ratio of 4:1. Which of the following statements would describe it?
    a. The bulk of the cell is composed of cytoplasm.
    b. The bulk of the cell is composed of nucleus.
    c. The proportions of cytoplasm and nucleus are roughly
    equal.
A

b. The bulk of the cell is composed of nucleus.

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