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प्रश्न
When we touch a hot plate unknowingly, then this heat is sensed by a receptor P present in our fingers. The receptor triggers and impulse in neuron Q 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.
(a) What is the name of (i) receptor P (ii) neuron Q, and (iii) organ R?
(b) What is (i) neuron S, and (ii) neuron T?
(c) Name the tissue U.
(d) What name is given to the phenomenon in which hand is pulled away quickly from the hot plate?
(e) Name the effector in this whole process.
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उत्तर
(a) (i) P is a thermoreceptor.
(ii) Q is a sensory neuron.
(iii) R is the spinal cord.
(b) (i) S is a relay neuron. The impulse from the spinal cord is passed on to a relay neuron.
(ii) T is a motor neuron. From the relay neuron, the impulse is passed on to a motor neuron.
(c) U is a muscle.
(d) Reflex action is the phenomenon in which the hand is pulled away quickly from a hot plate. It is performed automatically by an individual.
(e) The effector organ is the muscle of the arm.
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संबंधित प्रश्न
How are involuntary actions and reflex actions different from each other?
Which part of the eye contains cells which are sensitive to light?
What is meant by receptors and effectors? Give two examples of each.
Explain the difference between of the following pair of terms :
receptor and effector
Which of the following statements are true?
(i) sudden action in response to something in the environment is called reflex action
(ii) sensory neurons carry electrical signals from spinal cord to muscles in a reflex action
(iii) motor neurons carry signals from receptors to spinal cord in a reflex action
(iv) the pathway of transmitting signals from a receptor to a muscle is a reflex action
P is a cell (or group of cells) in the human body which is sensitive to a particular type of stimulus and conveys the messages to CNS through nerves Q. On the other hand, R is a part of the human body which can respond to a stimulus according to the instructions sent from the CNS through nerves S.
(a) What is P? Name five organs which contain cells (or group of cells) like P.
(b) Name the nerves Q.
(c) What is R? Give two examples of R.
(d) Name nerves S.
(e) How do messages travel through the nerves Q and S?
Your are driving your bicycle at a fast speed. Suddenly, a small boy comes in front of your cycle and, without wasting any time in thinking, you immediately apply the brakes and accident is avoided. What name is given to such an action?
With the help of suitable example, describe reflex action.
Differentiate between natural reflex and conditioned reflex. Give examples to illustrate your answer.
State whether the following is simple reflex, conditioned reflex or neither of the two.
Contraction of eye pupil
List in tabular form two differences between reflex action and walking.
What is a reflex action?
Reflex action is controlled by the
Explain the following term :
Conditioned reflex
Mention, if the following statement is True or False
Reflex action involves brain
Complete the following sentence with appropriate Word
A reflex arc in man is best described as movement of stimuli from:
Give an example for conditioned reflexes.
Reflex arc allows the rapid response of the body to a stimulus.
Which one of the following is not a simple reflex?
