Question

What does blood consist of?
A. 60% plasma, 40% corpuscles
B. 40% plasma, 60% corpuscles
C. 25% plasma, 75% corpuscles
D. 90% plasma, 10% corpuscles

Answer 1

Blood provides cells with nutrients, oxygen and other essential substances. It also removes waste or harmful substances like carbon dioxide, urea, etc. Blood contains mainly three types of corpuscles – RBC, WBC, platelets.

Complete answer:
Human blood consists of 60% plasma and 40% blood corpuscles. Plasma is the liquid part of the blood. It is straw, viscous coloured fluid. 90% - 92% of plasma consists of water and proteins contribute 6% - 8%. Fibrinogen, globulins and albumins are the major proteins. It also contains small amounts of minerals like $N{a^ + }$ , $C{a^{ + + }}$ , $M{g^{ + + }}$ , $HC{O_3}^ -$ , $C{l^ - }$ , etc. Glucose, amino acids, lipids, etc. are also present. Erythrocytes (RBCs), leucocytes (WBCs) and platelets are commonly called blood corpuscles. RBCs are the most abundant of all corpuscles. A healthy human adult man has 5 million to 5.5 million of RBCs mm-3 of blood. They are devoid of the nucleus and are biconcave in nature. They contain an iron-containing protein known as haemoglobin which serves as a carrier for oxygen. WBCs are the fighter cells of our body. They are colourless due to the lack of haemoglobin. There are 6000 – 8000 WBCs per mm3 of blood. They are categorised into granulocytes and agranulocytes. Granulocytes are further divided into neutrophils, basophils and eosinophils. Similarly, agranulocytes are further divided into monocytes and lymphocytes. Two types of lymphocytes are present – B lymphocytes and T lymphocytes. Platelets are also called thrombocytes. Blood normally contains 1,50,000 – 3,50,000 platelets per mm3. They help in the coagulation of blood.

Hence, the correct answer is option (A).

Note: Humans have a closed circulatory system which means blood is pumped by the heart and is circulated through a closed network of blood vessels. There are three main blood vessels present in our body.
-Artery: They carry oxygenated blood from the heart and distribute it to all cells in our body. The pulmonary artery is the only exception.
-Vein: They carry deoxygenated blood from all the cells in our body to the heart. The pulmonary vein is the only exception.
-Capillary: These are thin, single-layered blood vessels where the exchange of gases and nutrients takes place.