BLOOD
Composition & Function
Of Blood
What is Blood ?
Blood
• Blood is a liquid connective tissue
• Its volume is 5-6 Litres (i.e 8% of body weight
or 80 ml/kg body weight)
• Viscosity ranging from 4-5 times of water
• It is slightly alkaline, with a pH of ~ 7.4
• Its color varies from bright red to dark red
Hematocrit
• 45 % of the Total blood Volume containing
Packed Cell Volume is Haematocrit.
• It is also defined as ratio of total blood cells to
plasma.
Composition of Blood
Cellular Components
• Erythrocytes or Red Blood Corpuscles (RBCs)
Normal Count – 5 million/uL
• Leucocytes or White Blood Corpuscles (WBCs)
Normal Count – 4,000-11,000 / uL
• Platelets or Thrombocytes
Normal Count – 1.5 – 4 lakhs/uL
Plasma
• Pale yellow fluid made up of 91% water, 9% other
• 9% includes (8% Organic molecules, 1% inorganic
molecules)
Organic Molecules includes - Plasma Proteins
– Albumin- 55%
– Globulins- 38%
1. α- globulin
2. β- globulin
3. γ- globulin
– Fibrinogen- 7%
– Some amount of Prothrombin
Non Protein Nitrogenous substances-
Urea, creatinine, uric acid, bilirubin
• Nutrients: glucose, amino acids, lipids,
cholesterol
• Inorganic molecules-
Na+, K+, Ca++, Mg++, H+, Cl-, HCO3-, PO4--, SO4--
• Gases: O2 , CO2 , N2
Functions of Blood
Major functions of Blood
• Transport of:
– Gases, nutrients, waste products
• Regulation of temperature
• Protection against foreign substances
