Erythropoiesis is the production of RBCs . This ppt contains general and concised information about RBC production in prenatal, neonatal and in young and adult life.

1. Erythropoiesis (RBC production)
M. FARAN YOUSAF
• 2018-DVMN-038
• Group B (b)
• (Other members are 036,037,039,040 )
•
• Presented to : Dr. M. Sulman Ali Taseer

2. Outline:
• Introduction
• Sites of production
• Mechanism of production
• Stages of differentiation
• Regulation of RBC production
• References

3. Introduction:
• Hemopoiesis : Production of Blood (Hemo: Blood , Poiesis : Production)
It includes :
a) Erythropoiesis : Erythrocyte production
b) Leucopoiesis : Leukocyte production
c) Thrombopoiesis : Thrombocyte (platelets) production
etc…

4. Erythropoiesis:
• It is the process of development, differentiation and maturation of
RBCs from primitive stem cells.
• Two theories of blood production are given :
a) Monophyletic : There is a common parent cell of all formed
elements of blood.
b) Polyphyletic : Suggests different group of stem cells gives rise to
different blood cells..

5. Sites for
production:
• In the early weeks of embryonic life, primitive,
nucleated RBCs are produced in the yolk sac
(mesoblastic stage).
• During the middle trimester of gestation, the liver
is the main organ for production of RBCs, but
reasonable numbers are also produced in the
spleen and lymph nodes.(Hepatic stage)
• During the last month or so of gestation and after
birth, RBCs are produced exclusively in the bone
marrow. (Myeloid stage)

6. Sites for RBC
production:
• In Children Active bone marrow is present
throughout the axial skeleton and the long
bones like the tibia and femur etc.
• In adults(after 20 yrs) The accumulation of
fat in the bone marrow makes them inactive
for the production of RBCs (Yellow bone
marrow) and only few bones of axial
skeleton and ends of femur and tibia are
able to produce erythrocytes.

7. Mechanism:
• All blood cells start their lives in bone marrow from pluripotential
hematopoietic stem cell (PHSC)
• PHSC replicates and maintains its small proportion in the bone
marrow.
• PHSC reproduces and forms colony forming units also known as
committed stem cells e.g. CFU-E , CFU-GM
• These colony forming units form mature cells.

9. Stages of
differentiation:
• CFU-E forms a large no. of proerythroblasts.
• Proerythroblasts divide and produce a large no. of RBCs.
• First gen. of these are called basophil erythrocytes
because they dye with basic stains and have a little Hb.
• In the succeeding generations the cells become filled with
hemoglobin to a concentration of about 34 percent, the
nucleus condenses to a small size, and its final remnant
is absorbed or extruded from the cell. The endoplasmic
reticulum is also reabsorbed. The cell at this stage is
called a reticulocyte.
• Reticulocytes move from bone marrow to blood through
diapedesis and after 1-2 days it becomes a mature
erythrocyte.

10. Regulation of
RBC production:
• When tissue oxygenation decreases due to
several factors like Low blood volume,
Anemia, Low hemoglobin, Poor blood flow,
Pulmonary disease etc.
• Erythropoietin subsequently decreases.
• Kidney produces Erythropoietin which
stimulates the production of proerythroblasts
, thus speeding up the RBC production.

12. References:
• Guyton and Hall Textbook of Medical Physiology, 13th Edition
• Physiology of domestic animals-Sajjastad.
• Google
• Slideshare.net

13. Thank You.Any Questions?