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प्रश्न
Briefly explain the following terms : Reflex action
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उत्तर
Reflex action:
A reflex action is an involuntary and quick response of the body initiated because of a stimulus. The commands for a reflex action originate from the spinal cord.
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संबंधित प्रश्न
What are the various sense organs in our body?
When you smell a favourite food your mouth begins to water (that is, you secrete saliva). Write down what is the example of the gland which is stimulated to secrete saliva.
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.
Differentiate between natural reflex and conditioned reflex. Give examples to illustrate your answer.
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.
Sudden application of brakes of the cycle on sighting an obstacle in front
Explain the mechanism of reflex action with the help of a suitable diagram.
List in tabular form two differences between reflex action and walking.
Give an example for conditioned reflexes.
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.
