Human Blood

Human Blood

• Blood is a type of fluid connective tissue.
• The quantity of blood in the human’s body is Approximately 7 to 8% of the total weight of adult.
• This is a dissolution of base whose pH value is 7.4.
• There is an average of 5-6 litres of blood in human body.
• Female contains 4 to 5 litres of blood, less in comparison to male. This difference is due of size of body.
• Spleen act as storage organ for blood. It play an important role in the filtration of blood as part of immune system.

Blood consists of two part –

(A) Plasma and (B) Blood corpuscles.

(A) Plasma:

This is the liquid part of blood. 60% of the blood is plasma. Its 90% parts is water, 7% Protein, 0.9% salt and 0.1% is glucose. Remaining substances are in a very low quantity.

Function of Plasma:

Transportation of digested food, hormones, exeretory product etc form one part of the body to another part.

• Serum: When Fibrinogen and protein is extracted out of plasma, the remaining plasma is called serum.

(B) Blood corpuscles:

This is the remaining 40% part of the blood. This is divided into three parts –

1. Red Blood Corpuscles/ Red Blood Cells (RBCs)

2. White Blood Corpuscles/ White Blood Cells (WBCs) and

3. Blood platelets.

1. Red Blood Corpuscles (RBC):

Red Blood Corpuscles (RBC)/ Red Blood Cells of a mammal is biconcave.

• There is no nucleus. Exception – camel and Lama.
  New RBC is formed in Red Bone maroow.
  (At the embryonic stage its formation takes place in liver).
• Its life span is from 20 days to 120 days.
• Its destruction takes place in liver and spleen. Therefore, liver is called grave of RBC.
• It contains hemoglobin, in which haeme is iron containing compound and due to this the colour of blood is red.
• Globin is a proteinous compound. With haeme it is extremely capable of combining with oxygen and carbon dioxide.
• The iron compound found in hemoglobin, as hamatin.
• Normal range of hemoglobin content of an adult man is 17.5 gm/100 ml of blood.
• The main function of RBC is to carry oxygen from the lung to all cells of the body and bring back the carbon dioxide.
• Anaemia disease is caused du the deficiency of hemoglobin.
• At the time of sleeping RBC reduced by 5% and people who are at the height of 4200 meters RBC increases by 30% in them.
• Number of RBC is measured by an instrument called hemocytometer. In adult man its number range from 4 to 5 million per cubic millimeter.

2. White Blood Corpuscles (WBC) or Leucocytes:

Its shape is similar to Amoeba.

• Its formation takes place in Bone marrow, lymph node and sometimes in liver and spleen.
• Its life span is from 13 to 20 days. Normal range is usually between 4,000 to 11,000 per cubic millimeter.
• Nucleus is present in the White Blood Corpuscles.
• Its main function is to protect the body from the disease. The ratio of RBC and WBC is 600 :1.
• About 60 to 70% part of WBC is made up of neutrophile corpuscles which help in engulfing disease causing micro organism and bacteria.
• Lymphocytes are type of Leucocytes formed in bone marrow.
• ‘B’ and ‘T’ lymphocytes protect the body from disease caused by Pathogen.

3. Blood Platelets or Thrombocytes:

It is found only in the blood of human and other mammal.

• There is no nucleus in it.
• Its formation takes place in Bone marrow.
• Its life span is from 8 to 9 days.
• Normal platelet count ranges from 1,50,000 to 4,50,000 per cubic milliliter of blood.
• Its main function is to help inn clotting of blood.
• In dengue fever number of platelets reduced.

Functions of blood:

1. To control the temperature of the body and to protect the body from diseases. Normal temperature of the human body is 98.4°F(37°C).

2. Clotting of blood is known as Coagulation.

3. Transportation of O₂, CO₂, digested food, hormones, excretory material etc.

4. To help in establishing coordination among different body parts.

Clotting of Blood:

Three important reactions during clotting of blood.

1. Thromboplastin + Prothrombin + Calcium = Thrombin.

2. Thrombin + Fibrinogen = Fibrin.

3. Fibrin + Blood Corpuscles = Clot.

• The formation of Prothrombin and Fibrinogen of the blood plasma takes place with help of Vitamin K.
• The compulsory protein for making clots of blood is Fibrinogen.

Blood Group of human:

Blood group was discovered by Landsteiner in 1900. For this, he was awarded with Nobel Prize in the year 1930.

• The main reason behind the difference in blood of human is the glycol protein which is found in Red Blood Corpuscles called antigen.

Antigen are of two types – Antigen A and Antigen B.

• On the basis of presence of Antigen or Glyco Protein, there are four group of blood in human :

(a) That contains Antigen A – Blood Group A.

(b) That contains Antigen B – Blood Group B.

(c) That contains both the Antigens A and B – Blood group AB.

(d) That contains neither of the Antigens – Blood Group O.

An opposite type of protein, is found in blood plasma. This is called antibody. This is also of two types – Antibody ‘a’ and Antibody ‘b’. Therefore, with the four groups of blood division of antibody is as under -

Blood Transfusion:

Antigen ‘A’ and antibody ‘a’, Antigen ‘B’ and antibody ‘b’ cannot live together. In case of so happened these get most sticky, which spoil the blood. This is called agglutination of blood. Therefore in blood transfusion adjustment of Antigen and Antibody should be done carefully so that agglutination of blood do not takes place.

• Blood Group O is called Universal Donor because it does not contain any antigen.
• Blood Group AB is called Universal Receptor because it does not contain any antibody.

Rh factor:

In the year 1940, Landsteiner and Wiener discovered a different type of antigen in the blood. They discovered it in the Rhesus monkey; therefore, it is called Rh-factor. In the blood of that person it is found, their blood is called Rh-positive and in the blood of that person it is not found, is called Rh-negative.

At the time of blood transfusion Rh-factor is also tested Rh+ and Rh– is given Rh-blood only.

If the blood of Rh+ blood group is transferred to a person with Rh-blood group, then due to less quantity for the first time there does not seen any bad effect but if this process is repeated then due to agglutination the person with Rh-blood group dies.

• During transfusion, blood must be compatible not only in blood type but also in Rh factor.

Erythroblastosis Foetalis:

If the father’s blood is Rh+ and the mother’s blood is Rh– then the child to be born dies at the pregnancy or short span of time after the birth. (This happens in the case of the second issue).

The possible blood group of the child on the basis of blood group of mother and father.

Haemolymph: Body fluid of arthropoda is colourless made of plasma and haemocytes.

It does not contain any respiratory pigment. Ex – Cockroach.