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1. blood
Composition and functions of
blood and hematopoiesis.

2. Lecture 1 objectives
• Definition of blood
• Physical properties of blood
• Functions of Blood
• Components of blood : plasma & cells
• Plasma
• Types of Plasma Proteins
• Functions of Plasma Proteins
• Formation of cellular elements of
blood

3. Components of the Circulatory System
Heart = Pump
Blood vessel = Passageways
Blood = Transport Medium

5. Blood
Blood is a connective tissue with fluid matrix present
inside the cardiovascular system and plays an important
role in homeostasis.

6. Blood = connective tissue
Extracellular matrix:
Plasma (55%)
It is clear yellowish
fluid
specialized cells (45%)
(= cellular elements)
*- erythrocytes (red
blood cells)
*- leukocytes (white
blood cells)
*- thrombocytes
(platelets)

7. Physical properties of blood:
(1) Colour: red
due to presence of hemoglobin in RBCs. But the venous blood is
bluish in colour due to increased amount of reduced hemoglobin.
(2) pH:
7.4 (7.35-7.45) the venous blood is slightly acidic as it contains
more Co2 and metabolites from tissues
(3) Specific gravity (S.G.): (1.052-1.061)
It is the ratio between weight of certain volume of blood to the
weight of equal volume of distilled water.
S.G. of plasma = 1.030 & S.G. of RBCs = 1.090.

8. (4) Viscosity: about 5 times as water
-It determines the velocity of blood flow as its increase in
polycythemia (increase the red blood cells) lead to slow
circulation and increase resistance to blood flow with
increase in blood pressure and increase the load on the
heart which may cause heart failure.
5) Osmotic pressure: 5100-5500 mmHg
- It is due to presence of electrolytes, sugars, waste products (as urea).
- Plasma proteins have only 28 mmHg (called plasma colloid osmotic
pressure) but it is more important as it cannot pass the capillary
membrane.

9. Functions of Blood
Transport:
 Nutrients
 O2 & CO2
 Waste Products
 Hormones
Heat
 Electrolytes
Defense:
 Foreign organisms:
WBCs attack the
organism by
phagocytosis or
antibodies formation.
 Clotting process:
Prevent blood
loss from injured
vessels
Maintains Homeostasis
Regulation:
 water content
 pH
Metabolism
Body temperature
 Arterial bl. pressure

10. Plasma
Composition:
1- Water about 90%
2- Organic constituents:
• Plasma proteins 7.1-7.4%
• Nutrients, hormones, waste
products & enzymes 2%
3- Inorganic constituents 0.9%
NaCl, NaHCO3, KCl, CaCl2
Volume: 5% of body wt.
3.5 liter in adult 70 kgm

11. Albumin Globulin Fibrinogen Prothrombin
- Value 3.5-5 gm% 2.3-3.5 gm% 200-400mg % 10-15 mg %
- M.W 70.000 150.000 340.000 69.000
Synthesis Liver Liver
 1, 2, 1,
B2 types
lymphocytes
  type
Liver Liver
- Main
function
-Transporter
-Osmotic
pres.
regulation
- Carrier
-Defensive
function
-Viscosity
-Bl. Clotting
(factor I)
Act as clotting
factor II
Plasma Proteins

12. * Functions of plasma proteins
1) Blood clotting (haemostasis)
Fibrinogen, prothrombin and some clotting factors are plasma
proteins required for clot formation.
2) Defense (immunity)
by gamma globulin,  5 types of immunoglobulins (IgM, IgA, IgG, IgE, IgD)
to attack bacteria & virus.
3) Transport function
most of minerals and hormones are combined to plasma proteins
preventing its loss in urine.
4) Regulation of body fluids
as plasma proteins have osmotic pressure of 28 mmHg  shift of fluids from
tissue space to plasma  regulation of blood volume, tissue fluid and prevent
edema.
(albumin is responsible for this function as it has highest concentration and lowest
molecular weight)

13. * Functions of plasma proteins
5) Regulation of plasma viscosity
which regulate the peripheral resistance of blood flow 
regulation of diastolic blood pressure.
6) Control of capillary permeability
as the pores of capillary wall are partially blocked by plasma proteins
7) Buffer functions
plasma proteins are present as proteinic acid to buffer alkali and as Na proteinate
to buffer acids.
8) Nutritional functions
plasma proteins can be used by the tissues in prolonged starvation.
9) CO2 carriage
10) Specific functions

14. Differences between plasma and serum:
Plasma Serum
- Obtained by centrifugation
of blood sample after
adding of anticoagulant.
- Obtained by centrifugation of
clotted bl. sample
- Contains plasma proteins
and clotting factors
- Contains plasma proteins but
no clotting factors I, II, V &
VIII (consumed in bl. clotting)
- Clot on standing - Not clot on standing
- Normal serotonin level - Serotonin from broken
platelets with blood
coagulation

15. Blood volume
about 5 litres (3 L. plasma & 2 L RBCs) = 8% of body weight.
less in females
*- 7% of the blood in the heart
*- 18% in pulmonary system
*- 55% in veins
*- 15% in arteries
*- 5% in capillaries
Distribution

16. Variations in blood volume
Blood volume increases in :
1-Physiological causes
-Pregnancy -High altitude -Muscular exercise
2-Pathological conditions:
- Over transfusion of blood or I.V fluids - Polycythaemia
Blood volume decreases in:
- Dehydration: ( plasma) . - Haemorrhage: ( blood volume).

17. Formation of cellular elements of
blood
• Upto 5 yrs: all bone marrow
• Upto 20 yrs: bone marrow of membranous
+ ends of long bones
• After 20 yrs: bone marrow of membranous
bone

18. • Hematopoeisis: mechanism of blood cells
formation & stages of development
• Include:
• Erythropoiesis: formation of RBCs
• Leukopoiesis: formation of WBCs
• Thrormbopoiesis: formation of platelets.

19. • In adults the cellular elements are produced in the
bone marrow.
• •Some WBCs are produced in the lymphatic tissue
and bone marrow.
• •Blood cells need certain nutrients to form
properly.
• •Examples include…..
• —Iron
• —Folic acid
• —Vitamin B12

20. • •All blood cells formed come
• from a hematopoietic stem cell.
• •These cells can become any
• blood cell.

21. Hematopoiesis

22. Erythropoiesis: Formation of RBCs
• This development takes about 7 days and
involves three to four mitotic cell divisions,
so that each stem cell gives rise to 8 or 16
cells.