Biology
The diagram shows a reflex arc. Study it and answer the following questions.
- Name the parts numbered a to d.
- Using the letters of alphabet shown in the diagram, indicate the direction in which the impulse enters and leaves part c. X to Y or Y to X?
- What is reflex action?
- With the help of a flow chart, show a simple reflex action.
![The diagram shows a reflex arc. Study it and answer the following questions. 1. Name the parts numbered a to d. 2. Using the letters of alphabet shown in the diagram, indicate the direction in which the impulse enters and leaves part c. X to Y or Y to X? 3. What is reflex action? 4. With the help of a flow chart, show a simple reflex action. Nervous System in Humans, Living Science Biology Ratna Sagar Solutions ICSE Class 8.](https://cdn1.knowledgeboat.com/img/rb8/reflex-arc-diagram-living-science-biology-solutions-icse-class-8-631x395.jpg)
Answer
- The parts numbered a to d are:
a → sensory neurons
b → motor neurons
c → association neurons
d → cell body of motor neurons - The impulse enters through X and leaves through Y.
- An automatic, spontaneous and mechanical response to a stimulus; controlled by the spinal cord without the involvement of the brain is called a reflex action.
- Below flow chart shows a simple reflex action of immediate withdrawal of hand on touching a hot object:
![The diagram shows a reflex arc. With the help of a flow chart, show a simple reflex action. Nervous System in Humans, Living Science Biology Ratna Sagar Solutions ICSE Class 8.](https://cdn1.knowledgeboat.com/img/rb8/reflex-arc-pathway-living-science-biology-solutions-icse-class-8-395x883.png)