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प्रश्न
What will you do if someone pricks your hand with a needle? Elucidate the pathway of response with a neat labelled diagram.
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उत्तर
Reflex action and its pathway
The pathway taken by nerve impulses to accomplish reflex action is called the reflex arc.
- When the hand is pricked by a needle, the stimulus is the prick (touch) pain, which is sensed by a receptor called touch or pain receptors in the skin in our hand. This stimulus in tum triggers an impulse in a sensory neuron.
- The sensory neuron transmits or conveys the message to the spinal cord.
- The spinal cord interprets the stimulus and the impulse is passed on to the relay neuron, which in tum transmits it to a motor neuron.
- Motor neurons carry commands from the spinal cord to our arms.
- The muscle in our arm contracts and we withdraw our hand immediately from the needle prick. The muscle is the effector organ that has responded to the prick (pain).
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संबंधित प्रश्न
With the help of a neat and labelled diagram, describe reflex arc.
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.
Fill in the following blanks with suitable words :
Our.............system allows us to react to our surroundings. Information from receptors passes along...........neurons to our brain. Our brain sends impulses along..........neurons to our muscles.
Fill in the following blank with suitable word :
A neuron which carries an impulse to the brain is called a ........... neuron.
Explain the following term :
Conditioned reflex
State whether the following is
Sneezing
State whether the following is simple reflex, conditioned reflex or neither of the two.
Blushing
Give Reason:
The hand automatically shows the direction to turn a cycle without thinking.
Complete the following sentence with appropriate Word
The control of reflex action is through:
The reflex arc which is made up of one sensory and one motor neuron is ______
