1. (a) What is blood?
– Blood may be defined as-
(i) An opaque slightly, alkaline, salty taste, reddish coloured viscous conducting connective tissue fluid which is flowing through heart and blood vessels is called blood.
(ii) blood is soft specialized fluid connective tissue which is flowing constantly in a definite direction through heart and blood vessels.
(b) Total amount of blood- It means the whole amount of blood is present in the circulation as well as stored in certain organs like spleen, bone marrow, etc. The total amount of blood is present in healthy adult human is about 5 litres.
(c) The total amount of blood is expressed as- (i) In relation to body weight- it is 90 ml per kg of body weight.
(ii) In relation to body surface- it is 3.3 liters/ sq. meter body surface.
(d) Name of the instrument which is used to determine the total count of R.B.C. and W.B.C. is haemocytometer.
2. a) Why your blood looks red?
– The colour of the blood looks red due to presence of colouring pigment within the R.B.C. known as haemoglobin.
b) Mention the normal pH of human blood.
-The normal pH of blood varies between 7.3 and 7.4 (average pH of human blood).
3.a) What is haemoglobin?
– Haemoglobin is the red pigment of blood present in R.B.C.
b) Chemistry of haemoglobin.
– Haemoglobin is a choromoprotein (conjugated protein). It consists of 4% haem, a non protein iron containing pigment and 96% globin, a simple protein. Haem, the iron containing part is made up of iron (Fe++) and porphyrine. Hence haem also known as metalloporphyrin.
c) Normal amount of haemoglobin- (i) in adult male- 14.5 gm/ 100 ml and (ii) in female- 13.0 gm./ 100 ml. of blood.
d) Functions of haemoglobin:
i) Haemoglobin helps in transport of O2 and CO2 in the blood.
ii) It acts as buffer and thus maintains acid base balance.
iii) It forms different pigments such as bilirubin, billiverdin, etc.
e) Name of Instrument: The instrument by which the amount of haemoglobin is determined is known as haemoglobinometer.
4. Why blood is called connective tissue?
-Blood is known as connective tissue due to following reasons-
(i) connective tissue is made up of less number of cells and more amount of intercellular substances. Similarly blood also made up of less number (45%) of cells and more amount (55%) of plasma (intercellular substances).
(ii) similar to connective tissue the blood cells (R.B.C. and W.B.C. and platelets) remain apart from each other (suspended) within the plasma.
(iii) connective tissue connects different parts of the body, similarly blood by its circulation connects different parts of the body.
(iv) Connective tissue generally originates from mesoderm, blood also originates from mesoderm.
5.a) What are the types of haemoglobin found in the human body?
In man at least two varieties of haemoglobin are found such as -(i) Adult haemoglobin (HbA)-It is found in the R.B.C. of adult human blood. (ii) Foetal haemoglobin (HbF) – It is found in the R.B.C. of foetal blood. HbF has greater affinity for oxygen and releases CO2 more readily.
b) What is myoglobin?
-It is the respiratory pigment (like haemoglobin) of the muscle. like haemoglobin myoglobin is also protein in nature.
6.a) What is plasma?
– Plasma is the liquid part of the blood in which blood cells remain suspended. It contains the organic and inorganic substances.
b) Functions of plasma.
– (i) The fibrinogen and prothrombin are two plasma proteins which help in blood coagulation.
(ii) Albumin and globulin of plasma maintain viscosity and colloidal osmotic pressure of blood.
(iii) Acts as buffer and maintains the acid-base balance.
(iv) Acts as protein reservoir.
(v) Plasma helps in transport of various substances present in the blood.
7. What is total count (T.C.) of R.B.C.?
– The total number or total count (TC) of red cells present in the blood-
(i) In male- 5 million per cubic millimeter and
(ii) In female- 4.5 million per cubic millimeter.
8. What is the origin of R.B.C.?
a) In foetal life- The red blood cells are formed from spleen, thymus, liver at first and then from bone marrow.
b) After birth- The site of formation of R.B.C., after birth is mainly from red bone marrow.
c) Life span of R.B.C.- Normally the life span of R.B.C. is about 120 days.
8. Discuss some important functions of red blood cells.
(i) Transport of gases- Carriage of oxygen (as oxyhaemoglobin) and carbondioxide (as carbamino-haemoglobin) in the blood due to the presence of haemoglobin.
(ii) Maintenance of blood groups- The blood group substance (agglutinogens) are attached with the surface membrane of the red blood cells, thus they are responsible for blood group reactions.
(iii) Storage- Red cells store about two-third of total blood protein as chromoprotein (haemoglobin).
(iv) Formation of pigments- Haemoglobin in the red cell are responsible to produce bile pigments like bilirubin and biliverdin.
(v) Maintenance of acid-base balance- Haemoglobin acts as buffer and thus maintains acid base balance.
(vi) Maintains ion balance- By the special permeability of the cell membrane, the red cells maintain ionic (+ve & -ve) balance.