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Question
What are reflex actions? Give two examples. Explain a reflex arc.
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Solution
Reflex action is a sudden, spontaneous, automatic, involuntary response to the stimulus. It is an involuntary response as it is carried out without any conscious effort by the brain. The path along which the action is carried out is called the reflex arc.
Examples-
- Sudden withdrawal of hand while it comes in contact with a hot object.
- Narrowing of the pupil on exposure to bright light.
Reflex arc - The pathway of the nerve impulses involved during a reflex action constitutes the reflex arc. When there is a stimulus, it is first perceived by receptors present on the skin that send the stimulus in the form of an impulse, from the sensory neuron to the spinal cord. The spinal cord interprets the stimulus and sends the impulse to the motor neurons. The motor neurons in turn stimulate the effectors or muscles to respond to the stimulus.
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RELATED QUESTIONS
Reflex arc is formed by:
Assertion: Reflex Arc works faster than the thinking process of the brain.
Reason: Reflex Arc works in the case of those animals who do not have a thinking process.
Which is the correct sequence of the components of a reflex arc?
Which of the following statements are true?
- Sudden action in response to something in the environment is called reflex action
- Sensory neurons carry signals from spinal cord to muscles
- Motor neurons carry signals from receptors to spinal cord
- The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc
Junction between two neurons is called
Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in the given figure.
From where the following nerves arise.
Auditory nerve
Which one is NOT a reflex action?
Route of reflex arc is ______.
In the given diagram:
- Name the parts labelled A, B, and C.
- Write the functions of A and C.
- Reflex arcs have evolved in animals? Why?
Sensory nerve of a reflex arc carries information from the receptor cells to the ______.
Arrange and rewrite the terms in the group in the correct order to be in a logical sequence beginning with the term that is underlined:
Receptor, Response, Effector, Spinal Cord.
Arrange and rewrite the terms in group in the correct order to be in a logical sequence, beginning with the term that is underlined:
Effector, Receptor, Motor neuron, Sensory neuron.
Name the type of nerve which has the fibres of both sensory and motor neurons.
