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प्रश्न
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उत्तर
Following are the two examples of reflex actions in our daily life :
(i) Removing hand suddenly when pricked by a thorn.
(ii) Blinking of eyelids on exposure to light.
संबंधित प्रश्न
What is meant by receptors?
Which of the following are cerebral reflexes?
(i) a person pulls away his hand on touching a hot object
(ii) a person spits out immediately when a fly enters his mouth while talking
(iii) A person walking bare foot lifts his foot at once on stepping on to a nail
(iv) A person's pupil contracts at once in the presence of bright light
(a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (ii) and (iv)
Which of the following statements is correct about receptors?
One of the following gives the correct sequence of the components in a reflex arc. This is:
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.
Write down the following activities in the correct order for a simple reflex arc:
(a) impulse travels in the motor fibre
(b) impulse travels in the sensory fibre
(c) effector organ stimulated
(d) impulse crosses the synapse
List in tabular form two differences between reflex action and walking.
State whether the following is
Sneezing
State whether the following is
Constriction of pupil
Given alongside is a partial diagrammatic representation of a certain phenomenon pertaining to the nervous system.
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- Name the parts numbered 1-7.
- Name the phenomenon that the diagram depicts and define it.
- Give the technical term for the point of contact between two nerve cells.
- Name the parts not shown in the diagram that should be included to complete the pathway of the phenomenon.
