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Thursday, August 2, 2012


What is blood? Give the composition properties and function.

Ans; Blood is specialized fluid connective tissue in which there is liquid intercellular substance, plasma and formed elements (RBC,WBC,platelets ) suspended in the plasma which circulate in close system of blood vessels, it thick red and slightly alkaline.

          Composition of blood;
A.    Cellular substance: 45% (41%-46%)
1.      Erythrocytes or RBC
2.      Leucocytes    or WBC
3.      Thrombocytes or platelets
B.     Plasma :55% (55%-58%)
1.      Liquid substance –(91-92)%
2.      Solid substance   (8-9)%

*Inorganic substance;
                                 Sodium, potassium, calcium, iron, Zink , Magnesium,  phosphorus,                                                                                                                                    
                                 Copper etc.

*Organic substance; 7.5%
                                a. Protein : serum albumin, serum globulin, Fibrinogen, prothombin

                                b. Non protein:  Urea, Uric acid, xanthenes, Hypo xanthenes,                      
                                                            amino acid, creatine.
                           c. Fats;     Nutral fat, phospholipids,  cholesterol, cholesterides,
                                d. Carbohydrate: glucose, sucrose etc.
                                e. Other substance : internal secretion, anti-body, and other                    
                                                                     various enzymes .
                               f. Coloring matters: yellow colors of plasma is due to small             
                                                                   amount of  bilirubin

 Properties of Blood :
                                                       1.Blood volume : 5-6 liters.
                                                       2.Normal reaction : Slightly alkaline.PH 7.36 to 7.45
3.      Viscosity : 4.5 times more viscous then water.

4.      Taste : Salty.

5.      colour : Red.
Function of Blood:
1.      It transports respiratory gasses and nutrients, ( RBC)
2.      It acts as vehicles: Hormones, enzymes, vitamins, and other chemical are brought their places of activity through blood stream.
3.      It regulates body temperature.
4.      It regulates water and electrolytic balance.
5.      It maintains acid base balance.
6.      Defensive function :
a)      WBC is phagocyte properties engulf bacteria
b)      It develops antibody which combat toxic agent   
                                             7.  Excretory function: The metabolic end products and other                 
                                                   east products are carried by blood to the organ exertion      
                                                    with kidney .
                                            8.  Regulation of blood pressure : It regulates blood pressur
                                                     by changing volume and viscosity of blood.
                                             9.  It maintains colloidal osmotic pressure – By the action of   
                                                    plasma proteins .
                                            10. Prevent hemorrhage:  By the process of coagulation it   
                                                    prevent hemorrhage.

                                                                      Md. Jakir hossain
                                                               BHMS ( Dhaka Univesity)
                                                               MOB:  01936438687.
                                                               Web :

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