Question
4 The initiation of an action potential in a sensory neuron in the body normally
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GPT-4o mini
The initiation of an action potential in a sensory neuron typically occurs in response to a sensory stimulus. Here’s how the process works:
1. **Stimulus Detection**: Sensory receptors in the peripheral nervous system detect a specific type of stimulus (e.g., mechanical, thermal, or chemical). For example, a mechanical stimulus might be pressure applied to the skin.
2. **Generator Potential**: The sensory receptors undergo a change in membrane potential, generating a graded potential. This change occurs when ion channels open in response to the stimulus, allowing ions (like Na⁺) to flow into the cell and depolarize the membrane.
3. **Threshold Potential**: If the depolarization from the generator potential is sufficient to reach the threshold potential (typically around -55 mV), voltage-gated sodium channels in the sensory neuron's axon hillock will open.
4. **Action Potential Generation**: When the threshold is reached, a rapid depolarization occurs as Na⁺ ions rush into the neuron, leading to the rapid rise in membrane potential, which constitutes the action potential.
5. **Propagation**: The action potential then propagates along the axon to the central nervous system, where it is processed and interpreted as a specific sensation.
This process is critical for sensory perception, allowing the body to respond to various stimuli from the environment.
1. **Stimulus Detection**: Sensory receptors in the peripheral nervous system detect a specific type of stimulus (e.g., mechanical, thermal, or chemical). For example, a mechanical stimulus might be pressure applied to the skin.
2. **Generator Potential**: The sensory receptors undergo a change in membrane potential, generating a graded potential. This change occurs when ion channels open in response to the stimulus, allowing ions (like Na⁺) to flow into the cell and depolarize the membrane.
3. **Threshold Potential**: If the depolarization from the generator potential is sufficient to reach the threshold potential (typically around -55 mV), voltage-gated sodium channels in the sensory neuron's axon hillock will open.
4. **Action Potential Generation**: When the threshold is reached, a rapid depolarization occurs as Na⁺ ions rush into the neuron, leading to the rapid rise in membrane potential, which constitutes the action potential.
5. **Propagation**: The action potential then propagates along the axon to the central nervous system, where it is processed and interpreted as a specific sensation.
This process is critical for sensory perception, allowing the body to respond to various stimuli from the environment.