Red blood Cell

White Blood Cell

1. It is biconcave and disc shaped.

2. It lacks nucleus in matured condition.

1. It does not have a fixed shape.

2. It has distinct nucleus.

Blood cell

Red Blood Cell

White Blood Cell


No. of cells per ml of blood

4.5 million to 5 million


200,000 to 400,000

Site of production

Bone marrow

Bone marrow

Bone marrow


120 days

About 15 days

About 9 days

Blood transports different types of substances inside the body. It takes oxygen, glucose, nutrients, and hormones to different parts of the body. The blood also transports metabolic wastes and unwanted substances like carbon dioxide, urea and uric acid for removal from the body.
Those blood cells that are biconcave in shape, lack nucleus but contain hemoglobin are erythrocytes. These are also called red blood cells. They are formed in the bone marrow and destroyed in the liver and spleen after 120 days.
Red blood cells have hemoglobin in them. Each hemoglobin contains one iron ion in the 'haem'. The presence of these iron containing haem groups makes red blood cells appears red.
Anaemia is a condition when a person's body has fewer amounts of red blood cells. If a person suffers from iron deficiency, less hemoglobin will be made and this will result in fewer red blood cells.
Three functions of white blood cells are as follows:
  1. Some white blood cells fight against disease causing pathogens.
  2. Some white blood cells kill microorganisms.
  3. Some white blood cells help in removing the destroyed pathogens.
Platelets help in blood clotting. Because of the presence of platelets the soluble plasma protein fibrinogen is converted to insoluble fibrin that traps red blood cells and prevents bleeding.
There are various functions of blood. However, all these functions can be categorized into three main groups. Those three main groups are as follows:
  1. Transportation
  2. Regulation
  3. Protection

In leukaemia, cancerous blood cells form and crowd out the healthy blood cells in the bone marrow.Leukaemia is a condition in which the number of white blood cells(actually unnecessary blood cells) in the blood increases and becomes high. It is also called 'Blood cancer'. Leukaemia results due to the mutation in the gene that controls cell division.

Blood is the red and thick liquid connective tissue present in the human body. Blood is an important liquid connective tissue that circulates in a closed system of blood vessels. It is mainly made up of plasma and blood cells.
Generally following are the four components found in blood: -
  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
Plasma is yellowish transparent liquid. It occupies about 55% of the blood composition. It contains 90% of water, 10% of plasma protein, fat, salt and carbohydrate. The plasma protein contains the albumin, globulin and fibrinogen. Albumin is the most abundant protein in plasma.
The proteins found in plasma have following functions: -
  • To control the flow and the amount of water
  • To help clotting of blood
  • To protect from harmful germs invaded to our body
  • To maintain the blood pH
The fibrinogen and thrombocytes or platelets clots in contact with the air. Therefore, the blood when comes out gets clotted.
Hemoglobin is the substances which contains protein. It is found in the cytoplasm of erythrocytes of the blood in vertebrates. The function of the hemoglobin is to transport oxygen from the lungs to the cells.
Fibrinogen is a plasma protein which helps in clotting of blood by forming insoluble fibrin (a substance that form blood clot).
The three main functions of blood are as follows: -
  • The blood carries oxygen from the lungs to cells and tissues and carbon dioxide from the cells and tissues to the lungs.
  • It transports the food absorbed through intestine to the cells and tissues. It carries useless substances from the cells and tissues to the excretory organs such as liver, skin, kidney, etc.
  • It maintains body temperature and keeps the body warm.
  • It controls the amount of liquid and chemical in the body tissues.
  • It directs white blood cells towards the infected area.
  • Fibrinogen, fibrin and globulin help in clotting of blood in cuts and wounds. They also help quick healing of wounds.
Functions of RBC:
  • It transports oxygen and carbon dioxide between the lungs and all part of the body.
  • The surface of red blood cells absorbs the amino acids and transports them to the cells from the alimentary canal.
Functions of WBC:
  • It protects the body from micro-organisms and provides immunity to the body.
  • They produce antibodies and antitoxins which neutralize bacterial products.
Functions of platelets:
  • They perform an important role of forming clot on the skin in the event of an injury and prevent excess flow of blood from the body.
If a body consists minimum white blood cells (WBC), a person looses immunity power and may suffer from different types of disease. On the other hand, the excess of white blood cell in blood causes leukemia. Leukemia is blood cancer.
Anemia is caused due to the deficiency of RBC or erythrocytes. Due to its deficiency, the blood cannot transport enough oxygen to different body parts and enough energy is not released. Hence, person suffering from anemia becomes tired even in a short walk.
Blood comprises of red blood cell, white blood cell and platelets in the vicinity of plasma. So, in blood except red blood cells, other does not bear a particular colour. Each red blood cell (RBC) consists of hemoglobin containing iron. Because of this iron, the blood possesses red colour.
The two differences between red blood cell and white blood cell are as follows: -

Red blood cells
White blood cells
  1. Red blood cells have biconcave shape and do not bear nucleus.
  2. It is small in size.
  3. They help in transportation of oxygen and food materials.
  1. White blood cells are of different shapes and sizes and consist of nucleus.
  2. It is large in size.
  3. They protect the body from micro-organisms.
  1. Leukocytes: It protects the body from micro-organisms and provides immunity to the body.
  2. Bone marrow: It produces red blood cells.
  3. Fibrinogen: It helps in blood clotting.
Donated blood is treated with sodium citrate. It is because in the donate blood; fibrinogen is removed to avoid the blood clotting. Sodium citrate works as anti-coagulant.