Chapter 8- Erythrocyte production and Destruction Flashcards

1
Q

RBCs are formally called

A

Erythrocytes

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2
Q

The nucleated precursors in the bone marrow are called

A

erythroblast/ also called normoblasts

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3
Q

The stage of maturation of any blood cell is determined by careful examination of the

A

nucleus and the cytoplasm

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4
Q

qualities of greatest importance in identification of RBCs are the

A

nuclear chromatin pattern (texture, density, homogeneity), nuclear diameter, nucleus: cytoplasm ration, presence or absence of nucleoli, and cytoplasmic color

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5
Q

N:C

A

nuclear: cytoplasm

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6
Q

N:C

A

used to identify and stage red blood cell and white blood cell precursors.

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7
Q

the identifiable precursors of mature RBCs, in order from youngest to oldest

A

Pronormoblast, basophilic normoblast, polychromatic normoblast, orthochromic normoblast, polychromatic erythrocyte or reticulocyte.

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8
Q

days for the BFU-E (burst-forming unit-erythroid) to mature to an RBC

A

18-21 days

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9
Q

the mature erythrocyte has a life span of

A

120 days

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10
Q

two (2) functionally identifiable progenitors

A

BFU-E ( burst-forming units-erythroid)
CFU_E ( colony- forming unit- erythroid)
both committed to to the erythroid cell line.

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11
Q

Function of Erythrocyte

A

to carry oxygen from the lung to the tissues, where the oxygen is released. accomplished by attachment of oxygen to hemoglobin

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12
Q

process encompassing replication, to increase cell numbers and development from immature to mature cell stages

A

normoblastic proliferation

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13
Q

the earliest morphologically recognizable erythrocyte precursor

A

pronormoblasts

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14
Q

single pronormoblast

A

can usually result to 8-32 mature RBCs

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15
Q

commonly used stain in hematology

A

romanowsky stain, such as Wright-giemsa

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16
Q

Nucleus (pronormoblast)

A

Takes up much of the cell (N:C ratio of 8:1)

  • round to oval
  • containing 1-2 nucleoli
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17
Q

Cytoplasm(pronormoblast)

A

the cytoplasm is dark blue because of the concentration of ribosomes

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18
Q

Division(pronormoblast)

A

the pronormoblast undergoes mitosis and gives rise to two daughter pronormoblast.

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19
Q

Location (pronormoblast)

A

pronormoblast is present only in the bone marrow in healthy states.

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20
Q

Cellular activity (pronormoblast)

A

pronormoblast begins to accumulate the components necessary for hemoglobin production

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21
Q

length of time in this stage

A

this stage last slightly more than 24 hours

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22
Q

nucleus (Basophilic)

A

The chromatin begins to condense, revealing
clumps along the periphery of the nuclear membrane and a
few in the interior

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23
Q

Cytoplasm (Basophilic)

A

When stained, the cytoplasm may be a deeper,
richer blue than in the pronormoblast—hence the name
basophilic for this stage

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24
Q

Division (Basophilic)

A

The basophilic normoblast undergoes mitosis, giving rise to two daughter cells.

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25
Q

Location (Basophilic)

A

The basophilic normoblast is present only in

the bone marrow in healthy states

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26
Q

Cellular Activity (Basophilic)

A

Detectable hemoglobin synthesis occurs, but the many cytoplasmic organelles, including ribosomes
and a substantial amount of messenger ribonucleic acid (RNA;
chiefly for hemoglobin production), completely mask the
minute amount of hemoglobin pigmentation.

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27
Q

Length of time (Basophilic)

A

This stage lasts slightly

more than 24 hours

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28
Q

nucleus (polychormatic)

A

The chromatin pattern varies during this stage
of development, showing some openness early in the stage but
becoming condensed by the end.

29
Q

Cytoplasm (polychormatic)

A

This is the first stage in which the pink color

associated with stained hemoglobin can be seen

30
Q

Division (polychormatic)

A

This is the last stage in which the cell is capable
of undergoing mitosis, although likely only early in the stage.
The polychromatic normoblast goes through mitosis, producing daughter cells that mature and develop into orthochromic
normoblasts

31
Q

Location (polychormatic)

A

The polychromatic normoblast is present only in the bone marrow in healthy states

32
Q

Cellular Activity (polychormatic)

A

Hemoglobin synthesis increases, and the

accumulation begins to be visible in the color of the cytoplasm.

33
Q

Length of Time in This Stage. (polychormatic)

A

This stage lasts approximately 30 hours.

34
Q

Nucleus ( Orthochromic)

A

The nucleus is completely condensed (i.e., pyknotic) or nearly so. As a result, the N:C ratio is low or
approximately 1:2

35
Q

Cytoplasm ( Orthochromic)

A

The increase in the salmon-pink color of the cytoplasm reflects nearly complete hemoglobin production.

36
Q

Division ( Orthochromic)

A

The orthochromic normoblast is not capable of division due to the condensation of the chromatin

37
Q

Location ( Orthochromic)

A

The orthochromic normoblast is present only in the bone marrow in healthy states.

38
Q

Cellular Activity ( Orthochromic)

A

Hemoglobin production continues on the remaining ribosomes using messenger RNA produced earlier.

39
Q

Length of Time in This Stage ( Orthochromic)

A

This stage lasts approximately 48 hours.

40
Q

Nucleus (Reticulocyte)

A

when a cell loses its

nucleus, regardless of cytoplasmic appearance, it is a polychromatic erythroc

41
Q

Cytoplasm (Reticulocyte)

A

The cytoplasm can be compared with that of
the late orthochromic normoblast in that the predominant
color is that of hemoglobin.

42
Q

Division (Reticulocyte)

A

Lacking a nucleus, the polychromatic erythrocyte cannot divide.

43
Q

Location (Reticulocyte)

A

The polychromatic erythrocyte resides in the bone marrow for 1 day or longer and then moves into the
peripheral blood for about 1 day before reaching maturity.

44
Q

Cellular Activity (Reticulocyte)

A

The polychromatic erythrocyte completes production of hemoglobin from residual messenger
RNA using the remaining ribosomes.

45
Q

Length of Time in This Stage (Reticulocyte)

A

The cell typically

remains a polychromatic erythrocyte for about 3 days. 2 in bone marrow and 1 in peripheral blood

46
Q

Nucleus (erythrocytes)

A

No nucleus is present in mature RBCs.

47
Q

Cytoplasm (erythrocytes)

A

The mature circulating erythrocyte is a biconcave disc measuring 7 to 8 mm in diameter, with a thickness
of about 1.5 to 2.5 mm.

48
Q

Division (erythrocytes)

A

The erythrocyte cannot divide

49
Q

Location and Length of Time in This Stage. (erythrocytes)

A

Mature
RBCs remain active in the circulation for approximately 120
days.

50
Q

Cellular Activity (erythrocytes)

A

The mature erythrocyte delivers oxygen

to tissues, releases it, and returns to the lung to be reoxygenated.

51
Q

term describing the dynamics of RBC production and destruction

A

Erythrokinetics

52
Q

name given to the collection of all stages of erythrocytes throughout the body

A

Erythron

53
Q

Hypoxia

A

low oxygen levels in your tissues

54
Q

EPO (erythropoietin)

A

the primary hormone that stimulates the production of erythrocytes, is able to rescue the CFU-E from apoptosis, shorten the
time between mitoses of precursors, release reticulocytes from the
marrow early, and reduce the number of mitoses of precursors

55
Q

EPO

A
  • thermostable
  • nondialyzable
  • glycoprotein hormone with molecular weight of 34kD
56
Q

Apoptosis

A

is the mechanism by which an appropriate normal production level of cells is controlled.

57
Q

Which of the following is an erythrocyte progenitor?

a. Pronormoblast
b. Reticulocyte
c. CFU-E
d. Orthochromic normoblas

A

C

58
Q
  1. Which of the following is the most mature normoblast?
    a. Orthochromic normoblast
    b. Basophilic normoblast
    c. Pronormoblast
    d. Polychromatic normoblast
A

A

59
Q

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 normoblas

A

D

60
Q

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
progenitor

A

B

61
Q

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

62
Q

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

63
Q

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

64
Q

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

65
Q

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

A

A

66
Q

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

67
Q

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

68
Q

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