Blood is a complex fluid composed of plasma and cellular elements. Plasma is 90% water and contains proteins, nutrients, gases, and waste products. Blood performs two major functions: transport of oxygen, nutrients, waste, and more throughout the body; and defense of the body. Red blood cells contain hemoglobin and transport oxygen and carbon dioxide. They are produced through erythropoiesis in the bone marrow and liver under regulation of erythropoietin hormone.

1. Physiology of Circulating Body
Fluid: Blood
 Blood- Complex fluid of cellular
elements and actual fluid
-Plasma(55%), cellular elements(45%)
Cells free fluid after clotting - serum
Plasma:
Slightly alkaline, yellowish
90%water, 10% dry matter
9 parts organic matter
cholesterol, TG, phospholipids,
fat, protein, hormone etc)
and mineral (ionized form)

3. Physiology of Circulating Body
Fluid: Blood
 Blood performs two major
functions:
1.Transport
 Oxygen and carbon dioxide
 Food molecules (glucose,
lipids, amino acids)
 Ions ( Na+, Ca2+, HCO3
−)
 Wastes (e.g., urea)
 Hormones
 Heat
2. Defense of the body

4. What’s in plasma?
Water
Nutrients
Plasma proteins- 6-8g/dl
-albumins- 4-5 g/dl
-α and β globulin-2-3gm/dl
-γ globulin (antibodies)
-fibrinogen -0.3gm/dl
Origin: all except γglobulins are formed in the liver
γ globulin in B Lymphocytes (bone marrow, lymph node)
Gases; wastes
Physiology of Circulating Body
Fluid: Blood (Plasma)

5. Physiology of Circulating Body
Fluid: Blood
Functions of Plasma protein
 Osmotic pressure (25mmHg)
= maintain plasma volume
 Viscosity
Contribute half viscosity of blood
Depends on molecular shape
Fibrinogen contribute more
 Buffer function
C terminal buffer acid and NH3
alkali
Plasma

6. Functions of Plasma protein
 Protein reserve
during starvation and depletion
 Antibodies
Gamma globulin
 Clotting
Coagulation of blood
 Transport
Hormone and other small
molecules Globulin and albumin
 Cellular components of blood
Red Blood cells
Transport Hb
Significance of biconcave shape
-Swell before burst (hypotonic sol)
-Suited for squeezing
-Large surface area to volume
ratio- efficiency of O2 transfer

7. Physiology of Circulating Body
Fluid: Blood
 Size
Mean diameter- 7.5µm
Maxm thickness 2.5µm and 0.5 to 0.8 µm
 Normal count
♂: 5.2 Million/cu mm of blood
♀: 4.7 Million/ cu mm
High altitude
 Other characteristics
Mean corpuscular volume (MCV) = 90 cu microns
Mean corpuscular hemoglobin (MCH) = 30pg

8. Physiology of Circulating Body
Fluid: Blood
 Function (of RBC)
-Hemoglobin transport
-Oxygen transport
-Carbon dioxide transport
-Buffer system
No nucleus, no mitochondria,
no Ribosome, non insulin
dependent glucose transport
Life span 120 days

9. Haemoglobin
 Gives red blood cells their
colour
-Can carry up to 4 molecules
of O2
-Associates and dissociates
with O2
-Contains iron

10. Erythropoiesis = RBC
production
Granulopoiesis =
granular WBC Production
Hemopoietic Tissues =
responsible for production
of new blood cells
Physiology of Circulating Body
Fluid: Blood
 Production of RBC
Embryonic life- yolk sac
Liver spleen, lymph node
Bone marrow of all
bones (5 yr)
Hemopoiesis = formation
of blood cells,
Fig. Relative rates of RBC production

11. Physiology of Circulating Body
Fluid: Blood
2 Types:
- Myeloid Tissue (Red Bone
Marrow) = responsible for
production of most blood cell
- Lymphatic Tissue (Thymus,
etc.) = for formation of T-
lymphocytes, proliferation of
lymphocytes
Theories of Hemopoiesis
Monophyletic Theory:
All blood cells arise from a
single common stem cell
Diphyletic Theory:
Lymphocytes &
monocytes derived from
one stem cell (lymphoblast)
, granular leukocytes and
RBCs from another stem
cell (myeloblast)
Polyphyletic Theory:

12. Genesis of RBC ( Erythropoiesis)

13. Circulating Body Fluid: Blood
Erythropoiesis

14. Stages of Erythropoiesis
Proerythroblast
large cells (20-30µm) ,
large spherical nucleus,
prominent nucleoli,
basophilic cytoplasm
Basophilic Erythroblast
still large (15-20 µm), nucleus
round and proportionately
smaller, basophilic cytoplasm,
chromatin more condensed
Erythropoiesis
Principal processes involved
in differentiation of RBC:
- Reduction in size
- Condensation and eventual
loss of nuclear material and
organelles
- Acquisition of Hb via
protein synthesis
- Loss of proliferation
capabilities

15. Polychromatophilic erythroblast
• 12-15 µm in diameter, cytoplasm with diffuse
Basophilic (blue ; ribosomes) and acidophilic (pink; Hb)
staining , nucleus spherical and proportionately smaller
with chromatin more condensed
Orthchromatic erythroblast
• 8-10 micrometers, nucleus small and dark-staining
(condensed heterochromatin), cytoplasm pinkish
blue to pink
Circulating Body Fluid: Blood
Erythropoiesis

16. Reticulocyte
• 8-10 µm , no nucleus (extrusion has occurred), more
acidophilic cytoplasm but still some basophilic due to
ribosomes
• Diapedesis
Mature erythrocytes
• cytoplasm stains completely acidophilic
differentiation & maturation by 3 days
Circulating Body Fluid: Blood
Erythropoiesis

17. Circulating Body Fluid: Blood
Regulation of Red blood
cell Production
Tissue oxygenation
Anemia, High altitude ,
Cardiac failure , pulmonary
disease, low blood volume :
RBC production
Erythropoietin
Formation of RBC
(+ erythroblastic stages)
Vit B12 Folic acid
maturation of RBC
Androgen
+ Erythropoietin production
& Potentiates the action of
EPO, direct stimulation on
erthropoeisis
Estrogen
= - erthropoeisis
Thyroxine, cortisol, GH
= + erthropoeisis

18. Circulating Body Fluid: Blood
Erythropoietin
165 aa Glycoprotein, half life
5hrs; Source- 85% kidneys, liver
Mechanism of action:
number of erythropoietin
sensitive committed stem cell
in bone marrow : production
of proerythroblast and
proliferation and development
of other stage
EPO= DNA cleavage
followed by apoptosis site
of inactivation- Liver

19. Regulation of Erythropoietin

20. Physiology of Circulating Body
Fluid: Blood
• Formation of hemoglobin