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प्रश्न
Explain the structure and function of human blood.
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उत्तर
Blood is a fluid connective tissue that flows in blood vessels. It is composed of two components-plasma and blood cells.
Plasma is a yellowish colour fluid, made up of water (~90%) and some dissolved nutrients, proteins, hormones, and waste products.
Blood consists of three types of blood cells. These are
- Red Blood Cells: They contain a red pigment called hemoglobin, which transports oxygen to all body cells.
- White Blood Cells: They fight against germs that enter the body. Thus, they protect the body from diseases.
- Platelets: When we get injured, bleeding stops after some time. This happens because of the activity of platelets, which help in the clotting of blood.
Functions of blood:
- It transports nutrients and oxygen to the different parts of the body.
- It also carries waste materials (from the different parts of the body) to be removed by the excretory organs.
- Chemical messengers like hormones are transported by the blood.
- Protects the body from disease-carrying germs.
- Helps to maintain a constant body temperature.
संबंधित प्रश्न
Why is blood needed by all the parts of a body?
What is meant by human circulatory system? Name the organs of the circulatory system in humans.
Name the following:
The artery which carries deoxygenated blood.
Name the following:
The phase of the cardiac cycle in which the auricles contract.
Match the items in Column ‘A’ with those in column ‘B’ Rewrite the correct matching pairs.
| Column A | Column B | ||
| (a) | SA Node | (i) | Plasma |
| (b) | Defective haemoglobin in RBC | (ii) | Serum |
| (c) | Muscle fibres located in heart | (iii) | Pacemaker |
| (d) | The liquid squeezed out of blood during clotting | (iv) | Sickle cell anaemia |
| (e) | Never tires, keep on contracting and relaxing | (v) | Purkinje fibres |
| (f) | Cardiac cycle | (vi) | Cardiac muscle |
| (g) | Liquid part of the blood without corpuscles | (vii) | 0·85 sec |
Give any three differences between an artery and a vein
During surgical operations or during accidents, the patient may be given blood from outside to save his life. What is the technical name of this process? Briefly explain the precautions to be taken in this process.
Name the systems that carry out the different functions of the body.
The lymphatic system consists of which of the following?
______ is an agranulocyte.
