BLOOD

Notes prepared by RAMKRISHNA BHATTACHARYA, erstwhile R.M. of Sarabhai Piramal.

BLOOD

n Blood is a specialized fluid connective tissue. (Because the Plasma is more)

n Blood is the transport system of the body.

n Blood forms 8% of the body weight or 1/12 Th of the body weight.

n The adult male contains: - 5-5.5 lit. Of blood.

n The adult female contains: - 4.5- 5 lit. Of blood.

n Color of the blood:-

n Oxygenated- Brilliant red.

n De-oxygenated-Blackish red.

n Temperature of Blood- 38⁰ C.

n pH of Blood is 7.35 – 7.45(Slightly Alkaline)

n Specific Gravity of Blood – 1.05.

n Viscosity of Blood – 5 to 6 times more than water.

n Normal Blood Sugar Level- 80-120mg of Glucose/ 100ml (Adult).

BLOOD COMPONENTS

Composition of blood:-

Blood serum or plasma is a straw colored fluid, slightly alkaline in reaction. The composition of Blood serum or plasma is made up as follows:-

1. Water--- 91%.

2. Protein— 8%.

3. Salts----- 0.9%.

4. Other Trace Elements--0.1%

* Amongst Proteins, the following things are there: - Albumin, Globulin, Prothrombin, and Fibrinogen.

* Amongst Salts, the following things are there: - Sodium Chloride, Sodium Bicarbonate, Salts of Calcium, Phosphorus, Magnesium, and Iron etc

* Amongst Other Trace Elements, there are number of organic materials: Glucose, Fats, Urea, Uric Acid, Creatinin, Cholesterol, and Amino Acids.

ðThe plasma also carries:-

ðGases:- O₂ & CO₂

ðInternal Secretions.

ðEnzymes.

ðAntigens.

Ö Functions of the plasma: -

J Plasma protein is essential for the blood clotting.

J Plasma maintains colloidal osmotic pressure of blood and acids in regulating the distribution of fluid between blood and tissues.

J Plasma maintains viscosity and blood pressure.

J Plasma is concerned with Erythrocyte Sedimentation Rate.

J Plasma acts as buffers.

J Plasma acts as a protein reserve.

J Plasma helps CO₂ carriage by forming carbamino proteins.

J Plasma acts for defence against infection.

Blood has got mainly three components:-

v R.B.C. or Erythrocytes.

v W.B.C. or Leucocytes.

v Platelets or Thrombocytes.

R.B.C. or Erythrocytes. (Carries Haemoglobin.)

Erythro means Red, & cyte means pertaining to cell. There are 5(50lacs) millions of R.B.C.s in each cubic millimeter of blood.

The main functions of Erythrocytes are:-

Ø To transport O₂ & CO₂.

Ø To maintain acid & alkali balance.

Ø To colour the bile, stool, urine.

Ø Generated from red bone marrow.

Ø Helps to maintain the iron balance by the special permeability of the cell membrane.

Ø Helps to maintain the viscosity of the blood.

Ø Life span- 120 days.

Haemoglobin:-

Haemoglobin is a complex protein rich in iron. Its location found in the RBC. There are two parts of Haemoglobin. One part is GLOBIN & the other part is HEAM. Globin is broken down into AMINO ACIDS to be used as protein in the tissues and the iron in the HEAM is removed for use in the formation of future R.B.C.s. It has an affinity for oxygen, and combines with it forming oxy-haemoglobin in the red cells. By means of this function oxygen is carried to the tissues from the lungs.

The amount of Haemoglobin present in normal blood is about 15gm per 100 ml of blood, and this is usually called 100%.

Anything over 90% is considered normal.

In many forms of anaemia the amount of Haemoglobin present in the blood is diminished. In some severe forms it may fall bellow 30%, i.e. 5gm /100ml. As Haemoglobin contains the iron necessary to combine with oxygen, it will readily be understood that these patients present symptoms of deficient oxygen such as breathlessness, often one of the first indications of iron deficiency anaemia.

W.B.C. or Leucocytes.

Leuco means White & cyte means pertaining to cell. There is 5 thousand to 10 thousands of W.B.C.s in each cubic millimeter of blood. It is the smallest cell in the human body. Granulocytes or Polymorphonuclear cells (P.M. N) forms 75% of the total W.B.C.

The main functions Leucocytes of are:-

Ø To kill the invading microorganisms by Phagocytosis.

Ø To develop immunity against diseases.

Ø Formation of fibroblasts.

Ø Secretion of heparin.

Ø Generated from Lymph Nodes, bone marrow.

Ø Life span- 1to 15 days.

Platelets or Thrombocytes.

Thrombo means thrombin which helps in blood co-agulation cyte means pertaining to cell. There are about ¼ to ½ millions (2.5 lacs to 5 lacs) of Thrombocytes in each cubic millimeter of blood.

The main functions of Thrombocytes are:-

Ø To help in blood co-agulation.

Ø Generated from bone marrow.

Ø Life span- 3 to 10 days.

The normal blood count or the number of cells / cubic millimeter of blood is approximately:-

1. Red Blood cells: - 4,500,000 to 5,500,000. Average: - 5,000,000.

2. White blood cells: - 6,000 to 10,000. Average: - 8,000.

White blood cells are made up as follows:-

a) Granulocytes:-

® Neutrophil cells: - 60% to 70%. Average: - 66%.

® Eosinophil cells: - 1% to 2%. Average: - 3 %.

® Basophil cells: - ½ % to 2%.Average: - 1%.

b) Agranulocytes

Lymphocytes: - (Large & Small):- 20 to 30%. Average: - 25%.

Monocytes: - 4% to 8%. Average: - 5%.

Platelets: - 250,000 to 500,000. Average: - 350,000.

Life Span: - 2-3 days

BLOOD GROUPS

In the W.B.C.s of blood there are special types of polysaccharides in the capillaries of W.B.C.s which determines the blood group. They are known as AGGLUTINOGEN OR BLOOD ANTIGEN. There are two types of AGLUTINOGENS. A& B. Similarly there are two types of AGGLUTININ OR BLOOD ANTIBODY again subdivided in two groups α & β.

Blood is divided in four groups according to the presence & absence of AGGLUTINOGEN & AGGLUTININ.

Sl. No.	Blood Group	Agglutinogen	Agglutinin
1.	+A	A	β
2.	+B	B	α
3.	+AB	A&B	Nil
4.	+O	Nil	α & β

Type

Blood Group

Agglutinogen (ANTIGEN)

Agglutinin (ANTIBODY)

Can donate to which group?

From which group can accept?

Universal Donors

O.

________

α & β.

O,A,B,AB.

O.

Universal Acceptors

AB.

A,B.

________

AB.

A,B,AB,O.

Antigen & Antibody Reaction causes ALLERGY.

RHESUS FACTOR OR Rh-factor AND IMPORTANCE.

Scientists Landstainer and Winner in 1940, extracted Blood from a type of Indian Monkey Called Rhesus macacus, and entered this blood to Rabbits and in the serum they created a type of Antibody which was nomenclatured by the said Scientists, as Anti-Rh. This Antibody they entered in white people and their R.B.C.s were converted into lumps.

Afterwards the scientists proved that, in the R.B.C.s of human bodies there is same ANTIGEN like Rhesus macacus. So, according to the name of the Rhesus macacus monkey, that ANTIGEN is called Rh-factor.

The human beings who have this factor, their blood is called Rh±. Now they are subdivided into two groups: - Rh⁺ &Rh^--.

85% people have Rh⁺ factor in their blood.

This factor determines the compatibility of the foetus with MOTHER.

FUNCTIONS OF BLOOD:-

Blood has the following functions:-

v Transportation.

v Coagulation.

v Immunity.

v Protective.

v Regulation of temperature.

Functions of W.B.C.:-

The Granulocytes & Monocytes play a very important role in protecting the body microorganisms. By Phagocytic Action (Phago- I eat), they ingest living bacteria. As many as 10 to 20 microorganisms may be seen in a Granulocyte under microscopic examination. When performing this action they are called phagocytes. They have amoeboid (means amoeba like) movement. (For this movement Vit C is required.). So, they can move freely in and out of the blood vessels and wander about in all parts of the body.

In this way they can:-

Ü Surround any area which is infected or injured.

Ü They can take in living organisms and destroy them (Ingestion).

Ü Remove other materials.

Ü The Phagocytic Action of the W.B.C the inflammation may be completely arrested.

Ü Converted into Fibroblasts in an area of inflammation.

Functions of RBC: -

1. Maintains the acid-base balance.

2. Helps to maintain viscosity of blood.

3. Maintains the ion balance by the special permeability of the cell membrane.

4. Carry O₂ & CO₂.

5. Various pigments (Bilirubin, Biliverdin) are derived from Haemoglobin

6. Secrets Heparin which prevents intravascular clotting.

Functions of Thrombocytes: -

1. Helps in Clotting or Coagulation. (Clotting or Coagulation: - When blood is shed it losses its fluidity in a few minutes and sets into a semisolid jelly.)

When blood is shed, the platelets disintegrate and liberate thromboplastin. Certain amount of thromboplastin is also derived from the damaged cells of the injured tissue. Thromboplastin converts Prothrombin into Thrombin with the help of Calcium ions and Thrombin interacts with Fibrinogen forming Fibrin. This is the Clot.

Summary:-

Normal: -

Prothrombin + Calcium ion + Fibrinogen ¦ Nil

After shedding of Blood: -

1. Thromboplastin + Prothrombin + Calcium ion ¦ Thrombin

2. Thrombin+ Fibrinogen ¦ Fibrin (Clot),

SERUM & Differentiation of SERUM & PLASMA.

1. SERUM is the liquid part of blood which is left after Coagulation.

2. So, SERUM is PLASMA minus the blood clotting proteins.

Sl No	SERUM	PLASMA
1	Serum is the most fluid part of blood.	Plasma is the fluid part of blood.
2	Corpuscles and fibrinogen are not present.	Corpuscles are present.
3	Cannot be coagulated.	Can be coagulated properly.

TC & DC: -

TC: - The total number of WBC present in one Cubic Milliliter of blood is called TC or total count.

DC: - The proportional count of different WBC in 1 Cubic Milliliter of blood is called DC or Differential Count.

Normal DC or Differential Count of Human:-

Sl.No	Leukocyte (WBC)	%
1.	Eosinophil	4
2.	Basophil	1
3.	Neutrophils	65
4.	Monocytes	5
5.	Lymphocytes	25