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प्रश्न
What is the role of the brain in reflex action?
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उत्तर
Reflex actions are sudden responses, which do not involve any thinking. For example, when we touch a hot object, we withdraw our hand immediately without thinking as thinking may take time which would be enough to get us burnt. The sensory nerves that detect heat are connected to the nerves that move the muscles of the hand. Such a connection of detecting the signal from the nerves (input) and responding to it quickly (output) is called a reflex arc. The reflex arcs − connections present between the input and output nerves − meet in a bundle in the spinal cord.
Reflex arcs are formed in the spinal cord and the information (input) reaches the brain. The brain is only aware of the signal and the response that has taken place. However, the brain has no role to play in the creation of the response.
संबंधित प्रश्न
How are involuntary actions and reflex actions different from each other?
Which of the following is not a natural reflex action?
A. Knee-jerk
B. Blinking of eyes due to strong light
C. Salivation at the sight of food
D. Sneezing when any irritant enters the nose
Name the function of cerebrum.
Which of the following cannot be considered a receptor?
(a) ear
(b) nose
(c) muscle
(d) eye
One of the following controls the peristaltic movements of alimentary canal. This one is :
(a) cerebrum
(b) cerebellum
(c) pons
(d) medulla
The part of brain which controls the involuntary action such as heart beat, breathing, blood pressure, etc. is :
(a) pons
(b) medulla
(c) cerebrum
(d) cerebellum
Which of the following statements is correct about receptors?
The gustatory receptors of our body are in one of the following organs. This organ is :
a) ear
(b) nose
(c) tongue
(d) skin
Differentiate between the following pair of terms:
Stimulus and impulse
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
State whether the following is
Constriction of pupil
State whether the following is simple reflex, conditioned reflex or neither of the two.
Knitting without looking
State whether the following is
Blinking
State whether the following is
Salivation when food is put in the mouth.
Mention, if the following statement is True or False
A reflex action is a spontaneous response to a stimulus.
Complete the following sentence with appropriate Word
The control of reflex action is through:
A change in the environment that causes an animal to react is called ______.
Differentiate between Voluntary and involuntary actions.
Categorise the following under stimulus and response.
Withdrawal of hand on touching a hot plate
The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the following questions.
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- Name the phenomenon shown in the figure and define the same.
- Identify the parts labelled as 1 and 2. Write one functional difference between these two.
- Name the bony protective covering and the membranous protective covering of the spinal cord.
- Label the guidelines 3 and 4.
- How is the labelled part 3 different from part 4 with respect to its composition (part of neuron)?
- Give the technical term for the point of contact between the two nerve cells.
- Name the fluid filled inside the central canal of spinal cord.
- Name the term used for a small gap between two neurons.
- Give one example of a neurotransmitter.
- Draw a neat diagram of a nerve cell and label the parts: Perikaryon, Node of Ranvier, Myelin sheath and Axon terminals.
