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प्रश्न
Explain the structure and function of human blood.
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:
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It transports nutrients and oxygen to the different parts of the body.
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It also carries waste materials (from the different parts of the body) to be removed by the excretory organs.
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Chemical messengers like hormones are transported by the blood.
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Protects the body from disease-carrying germs.
- Helps to maintain a constant body temperature.
संबंधित प्रश्न
When a doctor is recording your pulse, he is pressing on your wrist exactly on a
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 reason for the following:
The walls of the left ventricle are thicker than the walls of all other chambers.
Given diagram shows a simple diagram of the circulation of blood in a mamma showing the
main blood vessels, the heart, lungs and body tissues. The blood vessel, labelled 6, contains
deoxygenated blood and the valve leading to it has three semi-lunar pockets.
(a) Name the blood vessels and organs marked by numbers 1 to 8.
(b) What is meant by the term ‘double circulation’ of blood in mammals?
(c) what is diastole?
[There is an “error” in the diagram. According to the usual practice the pulmonary (lung)
circulation is shown upward and the systemic downward, but here it is reversed].
Multiple choice questions. Tick ( ✓ ) the correct choice:
The four blood groups in humans are
State the Location: Bicuspid value
Analogy
Lungs: Respiratory system:: _______: Circulatory system.
In which of the following process blood neutrophils play an important role?
Which of the following is the main site of erythropoiesis in adults?
Name the following:
The structure that holds the heart valves in position.
