Question

What are the components of the blood?

Answer 1

Hint: Blood is a mobile connective tissue and it is the only way of transportation of O₂, nutrients, and other essential substances. It also helps to remove the waste and harmful substances from our bodies for the healthy functioning of cells. On average the blood volume is about 5 to 6 liters in an adult male or in a female is about 4 to 5 liters.
Complete answer:
Blood is a connective tissue composed of formed elements and blood plasma. Blood is a slightly alkaline fluid with a pH of 7.4. It constitutes 20- 30% of extracellular fluid.
Functions of blood:
Transportation of gases (O_2, CO₂), Hormones, heat, and wastes.
Regulation of pH, temperature, and water content of cells.
Protection against blood loss with the help of clotting factors.

Components of blood:
Plasma
Formed elements
Plasma: is a non-living intercellular substance that constitutes about 55% part of the blood. It is a pale-yellow viscous fluid. The composition of blood plasma:
90-92% of blood plasma is formed of water.
Plasma constitutes about 6-8% of protein and includes globulin, albumin, and fibrinogen.
It also contains a small number of minerals like Na⁺, Ca⁺⁺, Mg²⁺, HCO₃^-, Cl^- etc.
Plasma without the clotting factor called the serum.
Formed elements: Erythrocytes, leukocytes, and platelets are collectively called formed elements. They constitute 45% of the blood.
Erythrocytes: are also called RBC’s and are the most abundant cells in the human body. Its count in an adult human is about 5-5.5 million RBCs per cubic mm of blood. The life span of RBCs is 120 days.
Leucocytes: are also known as WBCs as they are colorless due to lack of haemoglobin. They are nucleated and their count is less than the RBCs, about 6000-8000 mm³ of blood. The life span of WBCs is generally short. It is of two types:
a). Granulocytes
b). Agranulocytes

Platelets: are also known as the thrombocytes produced from the bone marrow cells. They are colorless and are much smaller than the RBCs and WBCs. Its count in blood is 1,50,000-3,50,000 mm³. Platelets consist of a variety of substances, most of which are involved in clotting factors.

Note:
In blood, neutrophils are the most numerous while monocytes are the largest amongst all types of leukocytes. The blood group was first discovered by the ABO groups in 1990 by Karl Landsteiner. People who live in hilly areas have more RBCs as compared to people living in plain areas.