Which of the following statements about the response of neurones to stimulus is correct?
- Neurons respond to stimulus of any strength
- Neurons respond to all stimuli applied in rapid succession
- Neurons respond more rapidly during the absolute refraction period
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Intensity of stimulus must reach a threshold value before the neurons can be excited
The correct answer is: D
Explanation
Each neuron has a threshold that must be met before an action potential travels the length of the neurons axon. In other words, the neurons don't just begin to act immediately, there is a threshold value where the intensity of the stimulus must get to in order to yield a response from the neuron. This is why you can consciously pinch your self and not feel anything serious but when it is unconscious, it gives you serious pain.