Advertisements
Advertisements
प्रश्न
With the help of a neat and labelled diagram, describe reflex arc.
Sketch and label reflex arc
Advertisements
उत्तर
Reflex arc: The pathway of nerve fibers along which the reflex impulse travels is known as a reflex arc. It is always unidirectional from receptor organs to the effector organ, CNS. The reflex arc is the structural and functional unit of reflex action.
Components of simple reflex arc:
The simple reflex arc is formed of five components as given below:
1. Receptor organ:
It is a specialized part of the body called the sense organ that receives the stimulus and converts it into an impulse. e.g. skin, eye, tongue, nose, and ears.
2. Sensory or Afferent neuron:
It carries sensory nerve impulses from the receptor organ to CNS. Its cyton is located in the dorsal root ganglion. Its dendron is long and connected to a receptor, while the axon enters the grey matter of the spinal cord to form a synapse.
3. Associated or Intermediate neuron:
It is present in the grey matter of the spinal cord. It receives a sensory impulse, interprets it, and generates motor impulses.
4. Motor or effector neuron:
Its cyton is present in the ventral horn of grey matter and the axon travels through the ventral root. It conducts motor impulses from the spinal cord to the effector organ.
5. Effector organ:
It is a specialized part of the body that is excited by receiving the motor impulse. It gives a proper response to the stimulus. e.g. Muscles and glands.
APPEARS IN
संबंधित प्रश्न
How are involuntary actions and reflex actions different from each other?
Name the most important part of the human brain.
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.
Give the various functions of brain.
Which of the following are cerebral reflexes?
(i) a person pulls away his hand on touching a hot object
(ii) a person spits out immediately when a fly enters his mouth while talking
(iii) A person walking bare foot lifts his foot at once on stepping on to a nail
(iv) A person's pupil contracts at once in the presence of bright light
(a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (ii) and (iv)
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.
What type of reflex is the following?
Blinking of the eye
Which sensory organ is involved in vertigo (sensation of oneself or objects spinning around)?
Given alongside is a partial diagrammatic representation of a certain phenomenon pertaining to the nervous system.
 |
- Name the parts numbered 1-7.
- Name the phenomenon that the diagram depicts and define it.
- Give the technical term for the point of contact between two nerve cells.
- Name the parts not shown in the diagram that should be included to complete the pathway of the phenomenon.
