BLOOD – Red Blood Corpuscles or R.B.C.

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Red Blood Corpuscles

Ques. 1 What is Blood?
Ans. Blood is an opaque, rather viscid fluid, of a bright red or scarlet colour when it flows from arteries, of a dark red or purple colour when it flows the veins. It is salty to taste and alkaline in reaction, the pH of arterial blood ranging from 7.39 to 7.44. Its specific gravity is 1.055 to 1.066 and its temperature is generally about 37C.
Blood may be defined as a specialized connective tissue in which there is liquid intercellular substance known as plasma & formed elements, the red blood cells, the white blood cells & the platelets suspended in the plasma.

It is the fluid which acts as common nutritive medium by conveying food materials and oxygen to all tissues of body. It receives waste products of metabolic activities of tissues and carries them away to excretory organs, such as lungs and kidneys, by which they are eliminated.

Ques. 2 What are the Chief functions of blood?
Ans. The Chief functions of blood are :-
i. Drainage of waste products – It carries the waste products of cellular activity and brings them to the organ of excretion, viz. kidney, lungs, intestine etc.
ii. Maintenance of water balance – Blood maintains the normal water contents of the tissue.
iii. Maintenance of acid-base equilibrium – By its efficient buffering power and with the help of kindny, skin and lungs it helps to maintain a constant reaction of the body.
iv. Maintenance of ion belance between the cells and the surrounding fluid.
v. It acts as a vehicle through which the hormones, the vitamins and other essential chemicals are brought to their places of activity.
vi. Regulation of body temperature – The constant circulation serves to maintain the uniform temperature (in conjunction with the skin) at the different parts of the body.
vii. Defensive action – It acts as a great defensive mechanism in two ways viz. (i) the white cells due to their phagocytic properties engulf bacteria and foreign particles; (ii) it develops antibodies which combat toxic agents.
viii. By the property of coagulation it guards against haemorrhage.
ix. Regulation of blood pressure, by changes in volume and viscosity (haematocrit value) of blood.
x. Osmotic pressure – It maintains a steady osmotic pressure in the tissues and fluids of the body assisted by kidneys and skin.
xi. Transport of respiratory gases – It carries O2 from the lungs to the tissues and CO2 from the tissues to the lungs.
xii. Transport of nutrition – It carries digested food material absorbed from the intestine to the tissue cells for utilization. It also carries nutritive material from one place of the body to the other.

Ques. 3 What are the formed elements of blood?
Ans. There are three varieties of cellular elements in blood viz. red blood corpuscles, white blood corpuscles & platelets, which are collectively known as formed elements.
a) Reation – alkaline.
b) Total count (per cu. Mm) of R.B.C. : Men – 4.5 to 6.5 million; women – 3.5 to 5.5 million ; infants – 4.0 to 5.5 million ; children – 3.5 to 5.0 million – W.B.C.: Adults – 4000 to 11000 ; infants – 6000 to 20000 ; children – 5000 to 15000. Platelets : 1,50,000 - 5,00,000.
c) Specific Gravity 1.055 to 1.066.
d) Total volume about 4 to 5 litres.

Ques. 4 What is the Origin of Plasma Proteins?
Ans. The Origin of Plasma Proteins is : -
i. In the embryo, the primitive plasma and the plasma proteins are produced either by secretion or actual solution of the mesenchymal cells.
ii. The albumin, fraction is the first to be formed and the other varieties appear later.
iii. In the adults all the four fractions are produced by the liver. Fibrinogen, prothrombin and albumin are manufactured only in the liver.
iv. serum globulin are formed in the body probably (a) from the disintegrated blood cells, (b) from the reticulo-endothelial system, (c) from the tissue cells in general, (d) from lymphoid nodules.
v. The W.B.C. always undergo disintegration and certain amount of proteins are also discharged into the blood.

Ques. 5 What is the Composition of Blood?
Ans. Blood is highly complex fluid which is composed of two parts – a liquid, called the plasma & different types of cells which remain suspended in plasma. The cells are called blood corpuscles. The plasma constitutes about 55% and the cells about 45% of total volume of human blood. The general composition of the whole blood is as follows :
I. Cells – (i) White blood corpuscles or leucocytes (W.B.C.). (ii) Platelets or thrombocytes. (iii) Red blood corpuscles or erythrocytes (R.C.).
II. Plasma – (i) Solids (8 to 9%) (ii) Gases (nitrogen, oxygen, carbon dioxide etc.) (iii) Water (91 to 92%).
(A) Inorganic constituents (0.9%) –potassium, calcium, phosphorus, iron, copper, Sodium, magnesium etc.
(B) Organic constituents –
a) Fats: Neutral fat, phospholipid, cholesterol, cholesterides etc.
b) Carbohydrate. Glucose etc.
c) Other substances. Internal secretions, antibodies and various enzymes (amylases, proteases, lipases, phosphatases etc.).
d) Colouring matter. The yellow colour of plasma is due to small amount of bilirubin, carotene and xanthophyllin.
e) Proteins (7.5%). Serum globulin, fibrinogen, prothrombin etc.
f) Non-protein nitrogenous substances (NPN). Urea, uric acid, xanthine, hypexanthine, creatine, creatinine, ammonia, amino acides etc.

Ques. 6 What is Serum?
Ans. Blood serum is the clear liquid that separates from blood when it is allowed to clot completely, and is therefore blood plasma from which the fibrinogen has been removed during clotting (or it is plasma minus fibrinogen)
In normal individuals, average plasma proteins is about 7.0% It is made up of following varieties :
a) Serum globulin (1.3 to 2.5%) ;
b) Fibrinogen (0.2 to 0.4%). In addition to this about 0.1% of other proteins, such as
c) Prothrombin, seromucoid,
d) Serum albumin (4.7 to 5.7% ; etc.

Ques. 7 What is Plasma? What are the plasma proteins?
Ans. Blood plasma is a straw-coloured fluid, slightly alkaline in reaction i.e. the fluid portion of blood; which contains protein and the protein part of plasma is known as plasma protein.

Ques. 8 What does Plasma Protein finally gets converted into?
Ans. The plasma protein finally converts into tissue protein. The protein of the cells may be divided into 3 categories, viz.
a) Labile reserve protein which can be readily turned out into the blood stream to maintain the plasma protein concentration.
b) Fixed cell protein which is indispensible for cell life or activity;
c) Dispensable reserve protein which can be called upon for energy and other purposes in starvation ;

Ques. 9 Describe the composition of the blood plasma (plasma protein) and mention the function of its important constituents.
Ans. Composition:
a) Globulines – 2 to 3.5 gm/100 ml. Potassium – 3 to 5 meq./ 1. Phospholipid phosphorus -4 to 10 mg/ 100 ml.
b) Inorganic phosphorus – 2.5 to 5mg/ 100 ml.
c) Osmolality – 285 to 295 m OSm/kg. Non-proteinnitrogen (NPN) – 20 to 30 mg/100 ml. Magnesium – 2 to 3 mg/100 ml.
d) Lipids (total) – 400 to 800 mg/ 100 ml. Lactic acid – 5 to 10 mg/ 100 ml.
e) Ketone bodies – 0.7 to 1.5 mg/ 100 ml. Iron (male) – 70 to 180 mg/ 100 ml. Iron (female) – 50 to 150 mg/ 100 ml.
f) Glucose – 50 to 90 mg/ 100 ml.
g) Creatinine – 0.7 to 1.5 mg / 100 ml.
h) Cholesterol – 150 to 250 mg/ 100 ml. Calcium (total) – 9 to 11 mg/ 100 ml.
i) Bilirubin (total) – 0.5 to 1 mg / 100 ml. Bicarbonate – 21 to 27 mEq/ litre. Ascorbic acid – 0.4 to 1 mg/100 ml. Ammonium – 40 to 80mg / 100 ml. Pyruvic acid (fasting) – 35 to 80 mo1 / 1.Sodium – 132 to 14 meq/ 1.
j) Triglyceride (fasting) – 40 to 140 mg /100 ml.
k) Urea – 15 to 40 mg/ 100 ml.
l) Uric acid – 2 to 7 mg / 100 ml.
m) Total protein – 6 to 8 gm/ 100 ml.
n) Albumin – 3 to 5 gm/ 100 ml.

Ques. 10 What are the functions of plasma proteins?
Ans. Functions of plasma proteins :
a) They act as buffer substances ; and (i) help to preserve the reaction of the blood ; and (ii) aid in the transport of CO2
b) A complex of albumin and globulin takes part in immune reaction and helps in the defence processes of the body.
c) It has proved that the plasma proteins have involved in the body general metabolic pool of amino-acide.
d) The plasma proteins serve as a store-house of proteins from which the tissue can draw during starvation or inadequate protein diet.
e) Protein regulates the sedimentation rate. If fibrinogen and globulin concentration is high, the sedimentation rate is increased. It has got clinical importance.
f) Plasma protein helps in the transport of a number of materials such as lipids, drugs & metals, many of which appear to travel in the blood associated with one or more specific proteins.
g) Fibrinogen and prothrombin are essential for coagulation of blood – Fibrinogen is converted into fibrin when blood is shed and thus help in clotting of blood.
h) They exert and osmotic pressure of about 25 mm. of Hg. It is due to this osmotic pressure that they – (i) retain fluid in the capillaries, and so help to maintain blood volume ; (ii) regulate interchanges between the blood and the tissue spaces ; and (iii) influence filtration of plasma in glomeruli of the kidney.
i) The leucocytes prepare substances from the plasma proteins, called trephines, which are necessary for the nourishment of tissue cells grown in culture.

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