1Department of Biochemistry, CCS HAU, Hisar, Haryana, India 2Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India 3Nutritional Biotechnology, National Agri-Food Biotechnology Institute, Mohali, India *Corresponding author: yadavhariom@gmail.com

1. Jayanti Tokkas1, Shalini Jain2 and Hariom Yadav3*
1Department of Biochemistry, CCS HAU, Hisar, Haryana, India
2Department of Biochemistry, Postgraduate Institute of Medical Education and
Research, Chandigarh, India
3Nutritional Biotechnology, National Agri-Food Biotechnology Institute, Mohali, India
*Corresponding author: yadavhariom@gmail.com

2. BLOOD
 Connective tissue in fluid form
 Fluid of life – carries oxygen from lungs to all parts
of body and carbon-di-oxide from all parts of the body
to the lungs
 Fluid of growth – carries nutritive substances from
the digestive system and hormones from endocrine
gland to all the tissues.
 Fluid of health – protects the body against diseases
and get rid of unwanted substances by
transporting them into excretory organs like kidney.

3. Physical Characteristics of Blood
• Thicker than water
• 8 % of total body weight
• Blood volume
» 70 mL/kg of body weight
» 5 - 6 liters in males
» 4 - 5 liters in females
• Temperature - 100.40F
• pH - 7.35 to 7.45

4. Blood Functions
1. Respiratory
 Transport O2 from lungs to tissues
 Transport CO2 from tissues to lungs
2. Nutrition
 Transport “food” from gut to tissues
3. Excretory
 Transport waste from tissues to kidney (urea,
uric acid)
4. Protective
 White blood cells , antibodies, antitoxins.

5. Blood Functions
5. Regulatory
regulate body temperature
 regulate pH through buffers
 coolant properties of water
 vasodilatation of surface vessels dump heat
 regulate water content of cells by interactions with dissolved
ions and proteins
6. Body Temperature
 Water- high heat capacity, thermal conductivity, heat of
vaporization
 Typical heat generation is 3000 kcal/day

6. Blood composition
 Suspension of cells in plasma (carrier fluid)
45% Cells
55% Plasma
 Cells
Red cells (erythrocytes) 99%
5x106/mL
White cells (leukocytes)
7x103/mL < 1%
Platelets (thrombocytes)
3x105/mL

7. Blood composition

8. Blood Plasma
• Straw colored clear liquid
• Contains 90% water
• 7% plasma proteins
created in liver
confined to bloodstream
albumin
maintain blood osmotic pressure
immunoglobulins
antibodies bind to foreign
substances called antigens
form antigen-antibody complexes
fibrinogen
for clotting
• 2% other substances
Nutrients, electrolytes, gases, hormones, waste products

9. Functions of plasma proteins
1. Coagulation of blood – Fibrinogen to fibrin
2. Defense mechanism of blood – Immunoglobulins
3. Transport mechanism – α Albumin, β globulin transport
hormones, gases, enzymes, etc.
4. Maintenance of osmotic pressure in blood
5. Acid-base balance
6. Provides viscosity to blood
7. Provides suspension stability of RBC
8. Reserve proteins

10. Formed Elements of Blood
• Red blood cells (R.B.C.)
• White blood cells (W.B.C.)
 granular leukocytes
 neutrophils
 eosinophils
 basophils
 agranular leukocytes
 lymphocytes - T cells, B cells, natural killer cells
(N.K.C)
 monocytes
• Platelets (special cell fragments)

11. Functions of RBC
1. Transport oxygen from lungs to the tissues
(oxyhemoglobin).
2. Transport carbon-di-oxide from tissues to lungs
(carboxyhemoglobin)
3. Hemoglobin acts as a buffer and regulates the
hydrogen ion concentration (acid base balance)
4. Carry the blood group antigens and Rh factor

12. Functions of neutrophils
1. First line of defence against invading micro-
organisms.
2. Powerful and effective killer machine – contains
enzymes like protease, elastase, metalloproteinase,
NADPH oxidase; antibody like substances called
defensins.
Defensins – antimicrobial peptides active against bacteria and fungi.
3.Secrete Platelet Aggregation Factor (PAF) –
accelerates the aggregation of platelet during injury
to the blood vessels

13. Functions of eosinophils
Secrete lethal substances at the time of exposure to
foreign proteins/parasites
1. Eosinophill peroxidase – detroy worms, bacteria
and tumor cells.
2. Major basic protein – damage parasites
3. Eosinophill cationic protein (ECP)- destroys
helminths.
4. Eosinophill derived neurotoxin – destroys nerve
fibres (myelinated nerve fibres)

14. Functions of basophils
Basophill granules release some important substances like –
1. Histamine – Acute hypersensitivity reaction- vascular changes,
increase capillary permeability
2. Heparin – prevents intravascular blood clotting
3. Hyaluronic acid – necessary for deposition of ground
substances in basement membrane
4. Proteases – exaggerate inflammation
• Basophill have IgE receptor – hypersensitivity reaction

15. Functions of Platelets
1.Blood clotting
2.Clot retraction
3.Defence mechanism
4.Homeostasis
5.Repair and rupture of blood vessel

16. Gas transport
• Continuous interchange of CO2 and O2
between lungs and tissues.
• Oxygen –
• major e- acceptor
• indispensable for ATP production.
• CO2
• major by product of energy metabolism

17. pH maintenance
• Oxygen release helps to maintain pH in tissues
• Lungs:
– HHb + O2 = HbO2 + H+
• Tissues:
– CO2 forms proton and bicarbonate
– Proton is bound to Hb, when O2 is released
– Bicarbonate leaves RBC
• Cl- / HCO3- interchange - Hamburger effect

18. Hb
• Higher ability of Hb to release O2 but lower
ability to bind O2 - Right shift
• Useful at site of O2 release (tissues)
• higher temperature
• higher 2,3 BPG level
• lower pH (Bohr effect)

19. CO2 transport
1. Bicarbonate formation within RBC and Cl
interchange
2. CO2 dissolved in blood plasma
3. Carbaminohemoglobin formation