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प्रश्न
A person walks across a room in barefeet and puts his foot on a drawing pin lying on the floor. He lets out a cry. Explain what happens in his nervous system in bringing about this response.
उत्तर
It is an example of a reflex action. The stimulus in this example is pain which is felt by the foot on touching the drawing pin. This pain is sensed by a receptor in the foot. The receptor triggers an impulse to a sensory neuron which transmits the message to the spinal cord. Here, the impulse is passed on to a relay neuron which, in turn, passes it to a motor neuron. The motor neuron passes the impulse to a muscle in the foot. The muscle, then, contracts and pulls the foot away from the drawing pin.
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संबंधित प्रश्न
The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions:
1) Name the phenomenon that is depicted in the diagram. Define the phenomenon.
2) Give the technical term for the point of contact between the two nerve cells.
3) Name the parts numbered 1, 2 and 3.
4) How does the arrangement of neurons in the spinal cord differ from that of the brain?
5) Mention two ways by which the spinal cord is protected in our body.
If we happen to touch a hot object unknowingly, we immediately pull back our hand. What is this type of action known as?
Give the functions of medulla.
Explain the difference between of the following pair of terms :
receptor and effector
Multiple choice question. Tick (✓) the correct choice:
Reflex actions occur under the control of
- brain
- medulla oblongata
- spinal cord
- cerebrum
State whether the following is simple reflex, conditioned reflex or neither of the two.
Contraction of eye pupil
Two hungry boys (A and B) enter a restaurant and find a table decorated as follows:
Boy B starts salivating but not A. Explain the reason for this difference.
Mention, if the following statement is True or False
Reflex action is a unit of nervous action
Which of the following is an example of unconditioned reflex?
Which of the following is not an involuntary action?
