Biology Topics: MULTIPLE FACTORS (Blood Group)

Blood

Blood is a fluid connective tissue. The quantity of blood in the humans body is 7% of total weight. This is a dissolution of base whose pH value 7.4, there is an average of 5-6 litres of blood in the human body. Female contains half a litre of blood less in comparison to male.

History

At the beginning of the 20th century an Austrian scientist, Karl Landsteiner, noted that the RBCs of some individuals were agglutinated by the serum from other individuals. He made a note of the patterns of agglutination and showed that blood could be divided into groups. This marked the discovery of the first blood group system, ABO, and earned Landsteiner a Nobel Prize.

Landsteiner explained that the reactions between the RBCs and serum were related to the presence of markers (antigens) on the RBCs and antibodies in the serum. Agglutination occurred when the RBC antigens were bound by the antibodies in the serum. He called the antigens A and B, and depending upon which antigen the RBC expressed, blood either belonged to blood group A or blood group B. A third blood group contained RBCs that reacted as if they lacked the properties of A and B, and this group was later called "O" after the German word "Ohne", which means "without". The following year the fourth blood group, AB, was added to the ABO blood group system. These RBCs expressed both A and B antigens.

In 1910, scientists proved that the RBCs antigens were inherited, and that the A and B antigens were inherited codominantly over O. There was initially some confusion over how a person's blood type was determined, but the puzzle was solved in 1924 by Bernstein's "three allele model".

The ABO blood group antigens are encoded by one genetic locus, the ABO locus, which has three alternative (allelic) forms—A, B, and O. A child receives one of the three alleles from each parent, giving rise to six possible genotypes and four possible blood types (phenotypes).

Blood contains:-

1. Plasma

2. Blood cells/corpuscles

a. Red blood cells carry oxygen b.white blood cells fight infection c.Platelet stop bleeding in injuries

A. Plasma

Water-90%
Protein, salts, glucose-10%
This is the liquid part of blood 55% of the blood plasma.
It's 90% part is water, 7% Proteins, 0.9% salts and 0.1% is glucose, remaining substances are in a very low quantity.

The function of plasma:-

Transportation of digested food, hormones, excretory products etc. From the body take place through the plasma.

SERUM- when fibrinogen and protein is extracted out of plasma the remaining plasma is called 'Serum'.

B. Blood corpuscles

This is the remaining 45% part of the blood, this is divided into three parts-

1. Red blood corpuscles (RBCs)

2. White blood corpuscles (WBCs)

3. Blood platelets

A.Red blood corpuscles (RBCs) or Erythrocytes-

Red blood corpuscles of a mammal is biconcave.
There is no nucleus in it, exception camel and lama.
RBCs formed in Bone marrow (At the embryonic stage it's formation takes place in the liver).
It's life spanis from 90-120 days.
It's distraction takes place in the liver and spleen, therefore, the liver is called Grave of RBCs.
It's contains Haemoglobin [haemo- iron(Fe2+) and globin- protein (combine to O2 and CO2), in which haemo iron containing compound is found and due to this the colour of iron is red.
Globin is a proteinous compound which is extremely capable of combining with oxygen and carbon dioxide.
The Iron compound found in haemoglobin in haemin.
Anaemia disease is caused due to deficiency of haemoglobin.
At the time of sleeping RBCs reduce by 5% and people who are at the height of 4200 meters RBCs increases by 30% in them.

B. White Blood corpuscles (WBCs) or Leucocytes-

White blood corpuscles in shape and constitution this is similar to an amoeba.
It's formation takes place in Bone marrow, Lymph node and sometimes in liver and spleen.
It's life span is 3-5 days.
It's formation of antibodies which protect from disease/infection.
Nucleus present in it WBCs.

C. Blood platelets or Thrombocytes-