2. Where Does it Happen?
• Occurs in the Red Bone Marrow
• Red Bone Marrow is Found in the flat
bones of the:
1. Pelvis
2. Ribs
3. Sternum
4. Ends of the Femur and Humerus in
adults.
3. How is it controlled?
• Each blood cell type is produced
according to need
• Levels of the hormone Erythropoietin
(EPO) control the rate of RBC production
• EPO is produced by the kidneys
4. How does EPO work?
• We always have a little EPO flowing through us
to ensure constant RBC production
• If Oxygen levels fall, levels of EPO rise and more
RBC’s are produced
• The increase in EPO stimulates the red bone
marrow to produce the new cells
• High levels of oxygen in the blood will lower the
amount of EPO and slow down RBC production
5. The Hematocytoblast
• Common stem cell that gives rise to all the
formed elements of blood
• Located in the red bone marrow
• Forms two types of cells
1. Lymphoid Stem cell- produces all
lymphocytes
2. Myeloid Stem Cell- produces all other
formed elements (RBC’s plasma)
14. Amino
acids
Reused for
protein synthesis
Globin
Red blood cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+ Transferrin
Liver
Key:
in blood
in bile
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Heme
6
5
4
3
2
1
15. Amino
acids
Reused for
protein synthesis
Globin
Red blood cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+ Transferrin
Liver
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in blood
in bile
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Heme Fe3+
7
6
5
4
3
2
1
16. Amino
acids
Reused for
protein synthesis
Globin
Circulation for about
120 days
Red blood cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+ Transferrin
Liver
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in blood
in bile
Erythropoiesis in
red bone marrow
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Heme Fe3+
8
7
6
5
4
3
2
1
17. Amino
acids
Reused for
protein synthesis
Globin
Circulation for about
120 days
Red blood cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+ Transferrin
Liver
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in blood
in bile
Erythropoiesis in
red bone marrow
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Heme
Biliverdin Bilirubin
Fe3+
9
8
7
6
5
4
3
2
1
18. Amino
acids
Reused for
protein synthesis
Globin
Circulation for about
120 days
Bilirubin
Red blood cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+ Transferrin
Liver
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in blood
in bile
Erythropoiesis in
red bone marrow
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Heme
Biliverdin Bilirubin
Fe3+
1
0
9
8
7
6
5
4
3
2
1