Advertisements
Advertisements
प्रश्न
A person walks across a room in barefeet and puts his foot on a drawing pin lying on the floor. He lets out a cry. Explain what happens in his nervous system in bringing about this response.
Advertisements
उत्तर
It is an example of a reflex action. The stimulus in this example is pain which is felt by the foot on touching the drawing pin. This pain is sensed by a receptor in the foot. The receptor triggers an impulse to a sensory neuron which transmits the message to the spinal cord. Here, the impulse is passed on to a relay neuron which, in turn, passes it to a motor neuron. The motor neuron passes the impulse to a muscle in the foot. The muscle, then, contracts and pulls the foot away from the drawing pin.
APPEARS IN
संबंधित प्रश्न
Name one gustatory receptor and one olfactory receptor present in human beings.
If we happen to touch a hot object unknowingly, we immediately pull back our hand. What is this type of action known as?
Give three examples of reflex actions.
State whether coughing is a voluntary action or reflex action.
Fill in the following blank with suitable word :
A neuron which carries an impulse to the brain is called a ........... neuron.
What is spinal cord? What is its main function?
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?
Define reflex arc. Give the flow chart of a spinal reflex arc.
Give the various functions of brain.
A cell (or group of cells) in a sense organ which is sensitive to a particular type of stimulus is called :
(a) interceptor
(b) effector
(c) receptor
(d) acceptor
what do we refer to in the nervous system when we say:
Natural and conditioned …………………
State whether the following is simple reflex, conditioned reflex or neither of the two.
Contraction of eye pupil
List in tabular form two differences between reflex action and walking.
Reflex action is controlled by the
What type of reflex is the following?
Solving mathematical sums
What type of reflex is the following?
Formation of goose-pimples in cold weather.
Mention, if the following statement is True or False
Reflex action is a unit of nervous action
The reflex arc which is made up of one sensory and one motor neuron is ______
The given diagrammatic representation of reflex action shows knee jerk reflex.
Identify the parts labeled as A to E and select the correct option.
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.
