Blood is essential to tissue or plasma for life just like oxygen. All the body cells receive nutrients and oxygen via blood. All the waste and carbon dioxide take away from the cells by the blood. Generally, blood acts as a transporter as it takes the oxygen from the heart to the body cells and goes back to the heart with carbon dioxide to eliminate it from the body cells.
As it is mentioned earlier that blood is also called a tissue. It is so because blood contains the same cells to perform specific functions. Blood is fluid due to the suspension of these cells in it.
There is no replacement of blood or cannot make it artificially. If there is a blood patient or a person who has blood disease (thalassemia) will be on the mercy of blood donors. A man will die within minutes due to the unfavorable environment for the cell’s flow of blood will stop. Every normal body contains 5liter of blood.
Composition of blood
Continuously circulation fluid (blood) has two parts solid and liquid. A liquid part called plasma while solid parts are called red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
Red blood cells
About 45-45% of blood contains red blood cells. RBS carries oxygen and conveys it to the different places in the body. Hemoglobin, a protein has an iron that helps the blood to carry oxygen from one place and transfer it to the other place. When blood carries oxygen it gets darker. The life span of RBS is 4 months. After 4 months bone marrow make new RBCs after degeneration of old ones.
White blood cells
White blood cells also called leukocytes and you can also say them the guard of your body because they protect your body from any disease or microbial attack. No doubt they are just 1% of your blood but are extremely important in the defense system of your body. WBCs also produced in the bone marrow the same as RBCs.
Leukocytes have two groups’ granulocytes and agranulocytes. Granulocytes cells (neutrophils, basophils, and eosinophils) produced granules in blood, and agranulocytes cells (monocytes and lymphocytes) don’t have granules.
Functions of granulocytes and agranulocytes are given in following
Involved in phagocytotic activity
Produce heparin and histamine.
Involved in contravention the effects of histamine
It is involved in the immune system of the body. Some cells of lymphocytes directly attack the bacteria while some produce antibodies in this regard.
Involved in removing the dead cells from the body and kill the microorganisms by transforming themselves in the macrophages.
Platelets (thrombocytes) are not actually called cells but the small parts of megakaryocytes (found in bone marrow). Platelets help in blood clotting after any injury. Thrombocytes adhere to the damaged vessels and make the blood clot within a few minutes.
Plasma is the liquid part of the blood that contains proteins, water, and electrolytes, etc. function of plasma is the transportation of proteins, water, electrolytes, and other nutrients throughout the body and removes the waste from the body. Plasma occupies 90% of the blood. Reference:
Types of blood
Four types of blood are existing in nature.
Blood group A:
This blood group has A antigens at the surface of blood and anti-B antibodies in the plasma.
Blood group B:
This blood group has B antigens at the surface of blood and anti-A antibodies in the plasma
Blood group AB:
This blood group has both A and B antigens at the surface of blood with no antibody
Blood group O:
This blood group has no any antigens but both A and B antibodies in the plasma.
Rh factor decides whether the blood is positive and negative. Rh-negative factor makes the negative blood group while positive Rh factor makes a positive blood group.