Advertisements
Advertisements
Question
What is the role of the brain in reflex action?
Advertisements
Solution
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.
RELATED QUESTIONS
How do we detect the smell of an agarbatti (incense stick)?
Which part of the eye contains cells which are sensitive to light?
What is meant by receptors and effectors? Give two examples of each.
Give the functions of medulla.
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.
One of the following controls the peristaltic movements of alimentary canal. This one is :
(a) cerebrum
(b) cerebellum
(c) pons
(d) medulla
Your are driving your bicycle at a fast speed. Suddenly, a small boy comes in front of your cycle and, without wasting any time in thinking, you immediately apply the brakes and accident is avoided. What name is given to such an action?
Complete the following statement by choosing the correct alternative from the choice given in bracker:
Reflex action is controlled by
(i) brain (ii) spinal cord
(iii) autonomic (iii) peripheral nervous system
State whether the following is simple reflex, conditioned reflex or neither of the two:
Lifting up a book: …………………..
List in tabular form two differences between reflex action and walking.
What is a reflex action?
State whether the following is
Constriction of pupil
What type of reflex is the following?
Solving mathematical sums
Complete the following sentence with appropriate Word
The control of reflex action is through:
Complete the following sentence with appropriate Word
Which of the following is not a natural reflex action?
Differentiate between Voluntary and involuntary actions.
Categorise the following under stimulus and response.
Pain in the eye if something falls into it.
State whether the following is simple reflex, conditioned reflex or neither of the two.
Sneezing
The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the following questions.
 |
- 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.
