DAY TWENTY ONE
Body Fluids
and Circulation
Learning & Revision for the Day
u Blood u Human Circulatory System
u Lymph u Double Circulation
u Circulatory System u Disorders of Circulatory System
Blood
Blood is the most common body fluid connective tissue, which transports nutrients, oxygen,
essential substances and collects harmful substances for excretion from tissues. Blood is
a special connective tissue containing a fluid matrix, plasma and the formed elements.
(i) Plasma is a straw coloured, viscous fluid constituting about 55% of blood. It
contains fibrinogen, globulins, albumins, small amount of minerals like Na + ,Ca2+ ,
Mg2+ , HCO3− ,Cl−, glucose, amino acids, lipids, etc., and factors for coagulation.
(ii) Formed elements in blood are erythrocytes, leucocytes and platelets, which are
about 45% of blood.
l
Erythrocytes or Red Blood Cells (RBCs) are the most abundant elements. RBCs are
devoid of nucleus (nucleated in animals like frog) and biconcave in shape. RBCs are
formed in red bone marrow. A healthy person has 12-16 g of haemoglobin in every
100 mL of blood. RBCs have an average life span of 120 days, after which they are
destroyed in the spleen.
l
Leucocytes or White Blood Cells (WBCs) are nucleated and less in number of (average
6000-8000/mm3 of blood).
Leucocytes are mainly of two types :
Leucocytes
Granulocytes Agranulocytes
Neutrophils Eosinophils Basophils Lymphocytes Monocytes
(Phagocytic) (Resist infections) (Inflammatory (Phagocytic)
reactions)
B-lymphocytes T-lymphocytes
(Immune responses) (Immune responses)
, Platelets or thrombocytes are cell fragments produced by l
Thrombins are formed from prothrombin. An enzyme,
megakaryocytes (special cells in bone marrow). Blood thrombokinase is required for this reaction.
contains about 1,500,00-3,500,00 platelets mm.−3 Platelets are l
Coagulation of blood occurs by a series of linked enzyme
involved in clotting of blood. reactions (cascade process) involving a number of factors
present in plasma. Calcium ions also play an important
Blood Groups role in clotting.
Two types of blood grouping are widely used all over the l
The pathways or mechanisms of blood clotting are of two
world in humans. A ABO blood group is based on the types, i.e. extrinsic pathway and intrinsic pathway.
presence or absence of two surface antigens on the RBCs, i.e. It can be summarised as follows :
A and B. The plasma also contains two natural antibodies.
Extrinsic Pathway Intrinsic Pathway
Blood Groups and Donor Compatibility
Damage to tissue Damage to the
Antigen on Antibodies in outside the vessel blood vessel
Blood Donor’s Group
RBCs Plasma Plasma factors IV, V, VII, X Platelet cofactor form
A A Anti-B A, O Plasma factor IV, V, IX, X, XI, XII
Tissue Platelet thromboplastin
B B Anti-A B, O
thromboplastin (platelet factor 3)
AB A, B Nil AB, A, B, O
Inactive
O Nil Anti-A, B O Ca2+ and factor X Ca2+ and
proteins proteins
Person with blood group AB is called, universal recipient
Active factor X + Factor V
while person with blood group O is called universal donor.
Vitamin-K
Rh Group Prothrombinase
l
Rh group is based on Rh-antigen similar to that present in Inactivates heparin
rhesus monkey, it is also observed on the surface of RBCs
Prothrombin Thrombin
of about 80% of humans. Such persons are called Rh Ca2+
positive (Rh + ) and those, in whom antigen is lacking are Fibrinogen Fibrin
called Rh negative (Rh – ). Factor XII
l
Rh group should be matched before transfusion. An Rh – Serum Blood clot
person, if exposed to Rh + blood, will form specific
antibodies against the Rh antigens. Lymph
– + The fluid collected in the spaces between the cells of
l
The Rh blood of a pregnant mother does not mix with Rh l
antigens of the foetus in the first pregnancy as two bloods tissues is called lymph or interstitial fluid or tissue fluid.
will be separated by the placenta. However, during delivery l
Lymph contains water and same mineral contents as in
of the first child maternal blood may be exposed with the plasma. The network of vessels called lymphatic system
Rh + blood of the foetus. In such cases, the mother starts collects this fluid and drains it back to the major veins.
preparing antibodies against Rh antigen in her blood. l
Lymph is a colourless fluid containing special
l
In case of further pregnancies, the Rh antibodies of mother lymphocytes responsible for the immune responses of
(Rh − ) can leak into the blood of the foetus (Rh + ) and destroy the body.
the foetal RBCs. l
Functions of lymph are as follows
l
This could be fatal to the foetus and the condition is called ■Exchange of nutrients, gases, hormones, etc., occur
erythroblastosis foetalis. This can be avoided by through it.
administering anti-Rh antibodies to the mother ■It is responsible for the immune responses of the body.
immediately after the delivery of first child. ■Fats are absorbed through lymph in the lacteals present
in the intestinal villi.
Coagulation of Blood
l
In an injured or cut site, a clot or coagulation is formed Circulatory System
mainly of a network of threads called fibrins. Dead and
In higher and multicellular organisms, there is no direct
damaged formed elements of blood are trapped in fibrins.
supply of useful materials and removal of wastes from the
l
Fibrins are formed by the conversion of inactive fibrinogens body cells so, they need a transport system called circulatory
in the plasma by the enzyme thrombin. system. The circulatory system are generally of two types
Body Fluids
and Circulation
Learning & Revision for the Day
u Blood u Human Circulatory System
u Lymph u Double Circulation
u Circulatory System u Disorders of Circulatory System
Blood
Blood is the most common body fluid connective tissue, which transports nutrients, oxygen,
essential substances and collects harmful substances for excretion from tissues. Blood is
a special connective tissue containing a fluid matrix, plasma and the formed elements.
(i) Plasma is a straw coloured, viscous fluid constituting about 55% of blood. It
contains fibrinogen, globulins, albumins, small amount of minerals like Na + ,Ca2+ ,
Mg2+ , HCO3− ,Cl−, glucose, amino acids, lipids, etc., and factors for coagulation.
(ii) Formed elements in blood are erythrocytes, leucocytes and platelets, which are
about 45% of blood.
l
Erythrocytes or Red Blood Cells (RBCs) are the most abundant elements. RBCs are
devoid of nucleus (nucleated in animals like frog) and biconcave in shape. RBCs are
formed in red bone marrow. A healthy person has 12-16 g of haemoglobin in every
100 mL of blood. RBCs have an average life span of 120 days, after which they are
destroyed in the spleen.
l
Leucocytes or White Blood Cells (WBCs) are nucleated and less in number of (average
6000-8000/mm3 of blood).
Leucocytes are mainly of two types :
Leucocytes
Granulocytes Agranulocytes
Neutrophils Eosinophils Basophils Lymphocytes Monocytes
(Phagocytic) (Resist infections) (Inflammatory (Phagocytic)
reactions)
B-lymphocytes T-lymphocytes
(Immune responses) (Immune responses)
, Platelets or thrombocytes are cell fragments produced by l
Thrombins are formed from prothrombin. An enzyme,
megakaryocytes (special cells in bone marrow). Blood thrombokinase is required for this reaction.
contains about 1,500,00-3,500,00 platelets mm.−3 Platelets are l
Coagulation of blood occurs by a series of linked enzyme
involved in clotting of blood. reactions (cascade process) involving a number of factors
present in plasma. Calcium ions also play an important
Blood Groups role in clotting.
Two types of blood grouping are widely used all over the l
The pathways or mechanisms of blood clotting are of two
world in humans. A ABO blood group is based on the types, i.e. extrinsic pathway and intrinsic pathway.
presence or absence of two surface antigens on the RBCs, i.e. It can be summarised as follows :
A and B. The plasma also contains two natural antibodies.
Extrinsic Pathway Intrinsic Pathway
Blood Groups and Donor Compatibility
Damage to tissue Damage to the
Antigen on Antibodies in outside the vessel blood vessel
Blood Donor’s Group
RBCs Plasma Plasma factors IV, V, VII, X Platelet cofactor form
A A Anti-B A, O Plasma factor IV, V, IX, X, XI, XII
Tissue Platelet thromboplastin
B B Anti-A B, O
thromboplastin (platelet factor 3)
AB A, B Nil AB, A, B, O
Inactive
O Nil Anti-A, B O Ca2+ and factor X Ca2+ and
proteins proteins
Person with blood group AB is called, universal recipient
Active factor X + Factor V
while person with blood group O is called universal donor.
Vitamin-K
Rh Group Prothrombinase
l
Rh group is based on Rh-antigen similar to that present in Inactivates heparin
rhesus monkey, it is also observed on the surface of RBCs
Prothrombin Thrombin
of about 80% of humans. Such persons are called Rh Ca2+
positive (Rh + ) and those, in whom antigen is lacking are Fibrinogen Fibrin
called Rh negative (Rh – ). Factor XII
l
Rh group should be matched before transfusion. An Rh – Serum Blood clot
person, if exposed to Rh + blood, will form specific
antibodies against the Rh antigens. Lymph
– + The fluid collected in the spaces between the cells of
l
The Rh blood of a pregnant mother does not mix with Rh l
antigens of the foetus in the first pregnancy as two bloods tissues is called lymph or interstitial fluid or tissue fluid.
will be separated by the placenta. However, during delivery l
Lymph contains water and same mineral contents as in
of the first child maternal blood may be exposed with the plasma. The network of vessels called lymphatic system
Rh + blood of the foetus. In such cases, the mother starts collects this fluid and drains it back to the major veins.
preparing antibodies against Rh antigen in her blood. l
Lymph is a colourless fluid containing special
l
In case of further pregnancies, the Rh antibodies of mother lymphocytes responsible for the immune responses of
(Rh − ) can leak into the blood of the foetus (Rh + ) and destroy the body.
the foetal RBCs. l
Functions of lymph are as follows
l
This could be fatal to the foetus and the condition is called ■Exchange of nutrients, gases, hormones, etc., occur
erythroblastosis foetalis. This can be avoided by through it.
administering anti-Rh antibodies to the mother ■It is responsible for the immune responses of the body.
immediately after the delivery of first child. ■Fats are absorbed through lymph in the lacteals present
in the intestinal villi.
Coagulation of Blood
l
In an injured or cut site, a clot or coagulation is formed Circulatory System
mainly of a network of threads called fibrins. Dead and
In higher and multicellular organisms, there is no direct
damaged formed elements of blood are trapped in fibrins.
supply of useful materials and removal of wastes from the
l
Fibrins are formed by the conversion of inactive fibrinogens body cells so, they need a transport system called circulatory
in the plasma by the enzyme thrombin. system. The circulatory system are generally of two types
