1. Physiology of Red Blood Cells (RBCs) Erythrocytes
Structural characteristics
Hemoglobin
Erythropoiesis
Erythrocytes destruction
Anemia
Polycythemia

2. Filled with hemoglobin
Shape and Size of Red Blood Cells.
1 µm
No nucleus (anucleate) or organelles (no mitochondria, no endoplasmic reticulum)
biconcave discs having a mean diameter of about 7.8 micrometers and a thickness of 2.5 micrometers at the thickest point and 1 micrometer or less in the center. The average volume (MCV) of the red blood cell is 90 to 95 cubic micrometers (fL).
7.8
The red blood cell is a “bag” that can be deformed into almost any shape
Life Span of Red Blood Cells is About 120 Days
Filled with hemoglobin
Concentration of Red Blood Cells in the Blood
Men 5,200,000 (±300,000); women, it is 4,700,000 (±300,000)

3. Red Blood Cells
Function
O2 transport
CO2 transport
Buffer

4. RBCs concentrate Hb in their cytoplasm
Quantity of Hemoglobin Hb in the Cells.
RBCs concentrate Hb in their cytoplasm
Each 100 ml of RBCs , the concentration of Hb is about 34g (MCHC)
This is the maximum metabolic limit and normal people always Hb near the maximum value
If hematocrit (Hct) is normal, then Hb is one third of Hct value
Hct =45% then Hb = 15
Each gram of Hb can bind 1,34 ml of O2
So 100 ml of blood carry 20 ml of O2 in man
Women the amount is less.

5. Production of Red Blood Cells
Erythropoiesis

6. Production of RBC
Early few weeks of embryo nucleated RBCs are formed in yolk sac.
Middle trimester mainly in liver & spleen & lymph nodes.
Last months RBCs are formed in bone marrow of all bones
Bone marrow of flat bone continue to produce RBC into adult life
Shaft of long bone stop to produce RBC at puberty while epiphysis continued

7. Production of RBC

8. Genesis of RBC
All blood cell are formed from Pluripotential hematopoietic stem cells  committed cells:
Committed stem cells for RBC
Committed stem cells for WBC
Growth of different stems cells are controlled by different growth factors

9. Stages of Differentiation of Red Blood Cells
The first cell that can be identified as belonging to the red blood cell series is the proerythroblast
The first-generation cells are called basophil erythroblasts, very little hemoglobin
At the satge of reticulocytes, the nucleus condenses to a small size, and its final remnant is absorbed or extruded from the cell. At the same time, the endoplasmic reticulum is also reabsorbed
Reticulocytes pass from bone marrow into blood capillaries by diapedesis
In the blood stream the remaining basophilic material will disappear in 1-2 days and mature erythrocytes will developed

10. Formation of Hemoglobin
Red Blood Cells (cont.)
Formation of Hemoglobin
Fig Formation of hemoglobin
Fig Basic structure of hemoglobin

11. About 300 million molecules of HB in every red cell.
Each molecule of HB carries 4 oxygen O2 molecules.
Normal values:
Females: 14 g/100ml blood
Males: 15 g/100 ml blood
Oxygenated Hemoglobin
Bright Red (systemic)
*Deoxygenated Hemoglobin
dull (venous circulation)

12. Regulation of RBC production
Erythropoiesis is stimulated by erythropoietin hormone produced by the kidney in response to hypoxia (low oxygen in the blood)
Hypoxia caused by:
Low RBC count (Anaemia)
Hemorrhage
High altitude
Prolong heart failure
Lung disease

13. Tissue oxygenation and RBC formation

14. Erythropoietin Glycoprotein 90% from renal cortex 10% liver
Stimulate the growth of early stem cells
Does not affect maturation process
Can be measured in plasma & urine
High levels of erythropoietin
anemia
High altitude
Heart failure
Lung Disease
(Result in polycythemia)

15. maintain pliability of the cell membrane,
Life Span of Red Blood Cells is About 120 Days
RBCs contain cytoplasmic enzymes that are very important for:
metabolizing glucose and forming small amounts of ATP. These enzymes also
maintain pliability of the cell membrane,
(2) maintain membrane transport of ions,
(3) keep the iron of the cells’ hemoglobin in the ferrous form rather than ferric form, and
(4) prevent oxidation of the proteins in the red cells.

16. Destruction of RBCs take place in macrophages of the:
Spleen
Liver
Lymph nodes
urobilinogen

17. Anemias 1. Blood Loss Anemia. 2. Aplastic Anemia.
3. Megaloblastic Anemia.
4. Hemolytic Anemia.
Effects of Anemia on Function of the Circulatory System
Viscosity, resistance and cardiac output
Exercise

18. Polycythemia Secondary Polycythemia.
red cell count commonly rises to 6 to 7 million/mm3, about 30 percent above normal.
physiologic polycythemia
Polycythemia Vera (Erythremia)
Effect of Polycythemia on Function of the Circulatory System
Viscosity,