Question

Describe the nature of the generator potential and explain its relationship to stimulus intensity and to frequency of action potential production.

Short answer

The generator potential, or receptor potential, is the local change in membrane potential of a sensory receptor in response to a stimulus. It is a graded response dependent on stimulus intensity, where stronger stimuli generate larger generator potentials. When the generator potential reaches the threshold potential, it initiates an action potential in the neuron. Therefore, the frequency of action potential production is directly related to stimulus intensity, as stronger stimuli result in more action potentials.

Step-by-step solution

Define Generator Potential

Generator potential, also known as receptor potential, is the local change in the membrane potential of a sensory receptor in response to a stimulus. It is a graded response, meaning its amplitude is proportional to the strength of the stimulus. If the stimulus is strong enough and the generator potential reaches the threshold potential, this can trigger the production of an action potential in the neuron.

Define Stimulus Intensity

Stimulus intensity refers to the strength or magnitude of a stimulus. In the context of sensory receptors and neurons, it can be thought of as how strong the sensation or signal is that the receptor or neuron is responding to.

Describe Factors that Influence Generator Potentials

There are various factors that can influence the magnitude of a generator potential, including stimulus intensity, duration of the stimulus, and the specific type of sensory receptor involved. The stronger the stimulus, the greater the generator potential, which determines whether or not an action potential will be initiated.

Define Action Potential

An action potential, also known as a nerve impulse, is an electrical signal that travels along the membrane of a neuron. It involves a rapid, temporary change in the membrane potential from a resting state to a more positive state, and back to the resting state. The production of action potentials allows for communication and signal transmission within the nervous system.

Relationship between Generator Potential, Stimulus Intensity, and Action Potential Frequency

The generator potential, having the capacity to initiate an action potential, serves as the link between stimulus intensity and action potential frequency. When the stimulus intensity is high, it produces a stronger generator potential which, if it crosses the threshold potential, will generate an action potential. The number of action potentials generated in response to a given stimulus (action potential frequency) is directly related to the strength of the stimulus and the size of the generator potential it generates. In summary, the generator potential is a graded response to a stimulus, with its magnitude proportional to the stimulus intensity. When the generator potential reaches the threshold potential, it can initiate an action potential in the neuron. The frequency of action potential production is directly related to the stimulus intensity, as stronger stimuli generate larger generator potentials and correspondingly more action potentials.