RED CELL PRODUCTION AND DESTRUCTION

Question 1

Which of the following is an erythroid progenitor?

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

Answer 1

c

Question 2

Which of the following is the most mature normoblast?
A. Orthochromic normoblast
B. Basophilic normoblast
C. Pronormoblast
D. Polychromatic normoblast

Answer 2

A

Question 3

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.

Answer 3

Polychromatic normoblast

Question 4

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

Answer 4

b

Question 5

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

Answer 5

b

Question 6

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

Answer 6

D

Question 7

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.

Answer 7

a

Question 8

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

Answer 8

D

Question 9

True/False: Intravascular hemolysis is the result of trauma to RBCs while in circulation.

Answer 9

True

Question 10

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

Answer 10

C

Question 11

True/False: A pronormoblast belongs to the RBC mass of the body, but not to the erythron.

Answer 11

False

Question 12

A cell has an N:C ratio of 4:1. Which of the followig 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

Answer 12

B

Question 13

morphologically identifiable erythrocyte

precursors develop from two progenitors, ___________ and _______

Answer 13

burst-forming
unit-erythroid (BFU-E) and colony-forming unit-erythroid
(CFU-E)

Question 14

first morphologically identifiable RBC precursor

Answer 14

pronormoblast

Question 15

18 to 21 days

are required to produce a mature RBC from the BFU-E.. t OR f?

Answer 15

t

Question 16

N:C ratio is 8:1, The nucleus is round to oval, containing one or two nucleoli. The
purple red chromatin is open and contains few, if any, fine clumps, undergoes mitosis, present only in the bone
marrow in healthy states, Globin production begins.

Answer 16

Pronormoblast

Question 17

N:C ratio decreases to
about 6:1.
The chromatin stains deep purple-red. Nucleoli may
be present early in the stage but disappear later. undergoes mitosis, present only in the
bone marrow in healthy states, hemoglobin synthesis occurs, but the many cytoplasmic organelles, including ribosomes and a substantial amount of messenger ribonucleic acid (mRNA;
chiefly for hemoglobin production), completely mask the minute amount of hemoglobin pigmentation.

Answer 17

Basophilic Normoblast (Prorubricyte)

Question 18

N:C ratio is 1:1, This is the last stage in which the cell is capable of
undergoing mitosis

Answer 18

Polychromatic (Polychromatophilic) Normoblast (Rubricyte)

Question 19

The nucleus is completely condensed (i.e., pyknotic), N:C is 1:2, salmon pink colo

Answer 19

Orthochromic Normoblast (Metarubricyte)

Question 20

no nucleus. By the end of the polychromatic erythrocyte
stage, the cell is the same color as a mature RBC, salmon pink. It
remains larger than a mature cell, however. resides in the
bone marrow for about 1 to 2 days and then moves into the
peripheral blood for about 1 day before reaching maturity.

Answer 20

Polychromatic (Polychromatophilic) Erythrocyte

or Reticulocyte