Question

Give reason:

1. Valves are important in human heart. Give reason.

2. During rainy season wooden door generally swells up – Give reason.

3. Para sympathetic neural signals affects the working of the heart. Give reason.

4. Grapes placed in salt solution shrink. Give reason.

5. Why WBC’s are known as phagocytes?

Answer 1

1. The valves will prevent the back flow of blood.

2. It is due to imbibition. It is a type of diffusion in which a solid absorbs water and gets swelled up.

3. It reduce both heart rate and cardiac output.

4. It is due to exosmosis.

5. WBC produce antibodies during bacterial and viral infection and engulf the germs.