Activity 3.2 Let us understand further, To understand the role of blood and its components. Class 9
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Activity 3.2 Let us understand further, To understand the role of blood and its components. Class 9
Activity 3.2 Let us understand further
Aim: To understand the role of blood and its components in different body responses such as injury, infection, and exercise.
Observation:
Table: Your experiences, observations and questions from daily life
| Experiences | Observations | Questions |
| When you get a small cut on your skin | Red blood oozes out from the cut. A clot is formed after some time. | What causes blood to clot? |
| When you get a skin infection | The area turns red and perhaps slightly swollen. You may have a fever. | What causes redness swelling at the site of infection |
| When you exercise or run | You breathe faster. Your face may turn red. | Why does the breathing rate increase and face turn red during exercise. |
- A small cut on the skin results in red blood oozing out, followed by clot formation after some time. This indicates the presence of clotting agents in blood.
- A skin infection causes redness and swelling at the affected area, sometimes accompanied by fever. This indicates the body's immune response.
- During exercise or running, the breathing rate increases and the face turns red due to increased blood flow.
Explanation:
The everyday experiences mentioned above are related to blood and its components:
- The red colour of blood is due to haemoglobin, an iron-rich protein in the Red Blood Cells (RBCs). RBCs live for about 4 months and are replaced regularly.
- Platelets help in blood clotting at the site of injury, preventing excessive blood loss.
- During exercise or running, muscles need more oxygen, so breathing becomes faster and blood flow increases (face appears red).
- White Blood Cells (WBCs) collect at infected areas, causing inflammation (redness and swelling) and possible puls formation and fever at the infected area.
Conclusion: This activity demonstrates how blood functions as a connective tissue, with its various components - WBCs, RBCs and platelets- performing specific and coordinated functions in the body.