CBSE Quick Revision Notes (Class-11 Biology)
CHAPTER-18 BODY FLUIDS AND CIRCULATION
Body fluids are the medium of transport of nutrients, oxygen and other important substance in
the body.
Body Fluids
Intracellular Fluid Extracellular Fluid
(Fluid of of each cell) (Blood, Lymph, Cerebrospinal
fluid etc.)
Blood is the most commonly used body fluid in most of the higher organisms. Lymph also
transports certain substances like protein and fats.
Blood
Blood is a mobile connective tissue composed of a fluid, plasma and the cells, the blood
corpuscles. It forms about 30-35% of the extracellular fluid. It is slightly alkaline fluid
having pH7.4.
Plasma is straw coloured viscous fluid that constitutes 55% of blood volume. It consists of
90-92% water, 6-8% protein (fibrinogens, albumins and globulins), glucose, amino acids
and small amount of minerals like Na+, Ca++, Cl- etc.
Erythrocytes, leucocytes and platelets are collectively called formed elements.
Erythrocytes are most abundant cells in human body. Total blood count of RBCs is 5-5.5
million, which is slightly less in females due to menstruation. It is formed in bone marrow.
Nucleus is absent in mammalian RBCs having biconcave in shape.
Every 100 ml of blood contain 12-16 gm. of haemoglobin. They have life span of 120 days.
They are destroyed in spleen( graveyard of RBCs)
Leucocytes or WBCs are colourless due to absence of haemoglobin. 6000-8000 of WBCs are
present in each ml. of blood.
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, WBC
Granulocycts Agranulocyctes
Lymphocytes
Eosinophils
Basophils Monocyctes
Neutrophils
Neutrophils are most abundant and basophils are least abundant WBCs. Monocytes and
neutrophils are phagocytic cells which destroy foreign organisms.
Basophils secrete histamine, serotonin and heparin that involve in inflammatory reactions.
Eosinophils resist infection and allergic reactions. B and T lymphocytes are responsible for
immune response of the body.
Thrombocytes or platelets are cell fragments produced from megakaryocytes in bone marrow.
150000-350000 platelets are present in each ml of blood. Platelets are involved in clotting
or coagulation of blood in case of injuries.
Blood Groups – blood of human beings differ in certain aspects although it appear same in all
individuals. Two main types of grouping are ABO and Rh.
ABO grouping is based on presence or absence of two surface antigens RBC, antigen A and
antigen B. The plasma of an individual also contains two antibodies produced in response of
antigens.
• During blood transfusion, blood of donor has to be matched with blood of recipients to
avoid clumping of RBCs.
• Group ‘O’ blood can be donated to any individual with any blood group, so it is called
universal donor.
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CHAPTER-18 BODY FLUIDS AND CIRCULATION
Body fluids are the medium of transport of nutrients, oxygen and other important substance in
the body.
Body Fluids
Intracellular Fluid Extracellular Fluid
(Fluid of of each cell) (Blood, Lymph, Cerebrospinal
fluid etc.)
Blood is the most commonly used body fluid in most of the higher organisms. Lymph also
transports certain substances like protein and fats.
Blood
Blood is a mobile connective tissue composed of a fluid, plasma and the cells, the blood
corpuscles. It forms about 30-35% of the extracellular fluid. It is slightly alkaline fluid
having pH7.4.
Plasma is straw coloured viscous fluid that constitutes 55% of blood volume. It consists of
90-92% water, 6-8% protein (fibrinogens, albumins and globulins), glucose, amino acids
and small amount of minerals like Na+, Ca++, Cl- etc.
Erythrocytes, leucocytes and platelets are collectively called formed elements.
Erythrocytes are most abundant cells in human body. Total blood count of RBCs is 5-5.5
million, which is slightly less in females due to menstruation. It is formed in bone marrow.
Nucleus is absent in mammalian RBCs having biconcave in shape.
Every 100 ml of blood contain 12-16 gm. of haemoglobin. They have life span of 120 days.
They are destroyed in spleen( graveyard of RBCs)
Leucocytes or WBCs are colourless due to absence of haemoglobin. 6000-8000 of WBCs are
present in each ml. of blood.
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, WBC
Granulocycts Agranulocyctes
Lymphocytes
Eosinophils
Basophils Monocyctes
Neutrophils
Neutrophils are most abundant and basophils are least abundant WBCs. Monocytes and
neutrophils are phagocytic cells which destroy foreign organisms.
Basophils secrete histamine, serotonin and heparin that involve in inflammatory reactions.
Eosinophils resist infection and allergic reactions. B and T lymphocytes are responsible for
immune response of the body.
Thrombocytes or platelets are cell fragments produced from megakaryocytes in bone marrow.
150000-350000 platelets are present in each ml of blood. Platelets are involved in clotting
or coagulation of blood in case of injuries.
Blood Groups – blood of human beings differ in certain aspects although it appear same in all
individuals. Two main types of grouping are ABO and Rh.
ABO grouping is based on presence or absence of two surface antigens RBC, antigen A and
antigen B. The plasma of an individual also contains two antibodies produced in response of
antigens.
• During blood transfusion, blood of donor has to be matched with blood of recipients to
avoid clumping of RBCs.
• Group ‘O’ blood can be donated to any individual with any blood group, so it is called
universal donor.
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