Topic 24 - Hematopoiesis: Eythrocyte cell line

Question 1

Where does it occure and originate?

Answer 1

Occurs near vascular sinuses, originating from CFU-E (colony-forming unit erythrocyte).

Question 2

What are the stages and how long time do they take?

Answer 2

require 5-7 days:

• Rubriblast
• Prorubicyte
• Basophillic rubricyte
• Metarubricyte
• Reticulocyte
• Erythron

Question 3

Rubriblast

Answer 3

large cell and nucleus. Decreases in size as it divides. Stains blue.

Question 4

Prorubicyte

Answer 4

rounded, slightly smaller cell, basophilic due to high presence of ribosomes. Nucleoli absent.

Question 5

Basophilic rubricyte

Answer 5

basophilic due to ribosomes, red due to appearance of hemoglobin, nucleus of clumped chromatin.

Question 6

Metarubricyte

Answer 6

pyknotic (condensed) nucleus, increase in hemoglobin causes nucleus to shrink, end of division. The smallest nucleated erythrocyte with picnotic nucleus.

Question 7

Reticulocyte

Answer 7

Minimal remnants of ribosomes. Capable of O2 and CO2 transport. Modulation to become erythrocyte sees ejection of nucleus and removal of ribosomes and ER. Requires 1-2 days of maturation.

Question 8

Erythron

Answer 8

mass of circulating erythrocytes and marrow erythropoietic tissue

Question 9

Erythroblastic islands

Answer 9

group of erythrocytic cells within bone marrow organized around macrophage, most mature erythrocytes are at periphery.

Question 10

Efficacy of erythropoiesis in a dog:
time
development

Answer 10

• 1 million/second
• Development is regulated by hormones and cellular factors (oxygen level), development is accelerated by erythropoietin (released form kidney)

Question 11

Erythrocyte kinetics

Answer 11

• Development of rubriblasts to mature erythrocytes: 5-7 days
• Reticulocytes: normally 1-2 days maturation within the bone marrow
• Regulation of erythrocyte formation: cellular and humoral factors
• erythropoietin: key-molecule produced in the kidney