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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
Name one gustatory receptor and one olfactory receptor present in human beings.
The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions:
1) Name the phenomenon that is depicted in the diagram. Define the phenomenon.
2) Give the technical term for the point of contact between the two nerve cells.
3) Name the parts numbered 1, 2 and 3.
4) How does the arrangement of neurons in the spinal cord differ from that of the brain?
5) Mention two ways by which the spinal cord is protected in our body.
State one function each of cerebellum and pons.
Name two parts of the body which contain receptors of chemical stimuli.
State whether coughing is a voluntary action or reflex action.
What is the difference between a voluntary and an involuntary action? Which kind of action is digestion? Explain your choice.
When you smell a favourite food your mouth begins to water (that is, you secrete saliva). Write down what is the example of the cells in your nasal passages which perceive the smell?
Which of the following cannot be considered a receptor?
(a) ear
(b) nose
(c) muscle
(d) eye
Which of the following is not an involuntary action?
(a) vomiting
(b) chewing
(c) heart beat
(d) salivation
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:
Sneezing: …………….
State whether the following is simple reflex, conditioned reflex or neither of the two.
Contraction of eye pupil
Two hungry boys (A and B) enter a restaurant and find a table decorated as follows:
Boy B starts salivating but not A. Explain the reason for this difference.
Explain the following term :
Conditioned reflex
State whether the following is
Cleaning
What type of reflex is the following?
Knitting and swimming
The reflex arc which is made up of one sensory and one motor neuron is ______
If after cutting through dorsal root of a spinal nerve of a mammal, the associated receptor in skin was stimulated the animal would ______.
