When we touch a hot plate unknowingly, then this heat is sensed by a receptor P present in our fingers. The receptor triggers an impulse in neuron R which transmits the message to an organ R which is a part of the central nervous system. Here the impulse is passed on to a neuron S which in turn passes it to a yet another neuron T. The neuron T passes the impulse to a tissue U in our arm. The tissue U then contracts and pulls our hand away from the hot plate. Read the given paragraph and look at the image above. Now, answer the following questions:
1. What is the name of receptor P ?
(i) Thermoreceptor
(ii) Olfactory receptors
(iii) Taste receptors
(iv) None of the above
2. Name the organ R.
(i) Heart
(ii) Spinal cord
(iii) Kidney
(iv) Lungs
3. What is neuron S ?
(i) Motor neuron
(ii) Sensory neurons
(iii) Relay neuron
(iv) None of the above
4. What name is given to the phenomenon in which hand is pulled away quickly from the hot plate ?
(i) Reflex action
(ii) Thermal action
5. Name the effector in this whole process
(i) Muscle (of arm)
(ii) Muscle (of leg)
(iii) Bone of arm
