PHSYIOLOGY BLOOD UNIT 1

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