No, the amplitude of an action potential is constant and does not vary with the strength of the stimulus. Instead, the frequency of action potentials fired by a neuron can increase with a stronger stimulus.
The relative refractory period is the phase of the cardiac action potential during which a stronger-than-usual stimulus is required to elicit another action potential. It occurs immediately following the absolute refractory period and allows for the heart muscle to be able to respond to a second, stronger stimulus after the initial action potential.
The simplest behavior where a stimulus provokes an atomic response is a reflex. This is an involuntary, automatic response to a stimulus without conscious thought. For example, when your hand touches a hot surface, your reflex action is to pull your hand away immediately.
Increased stimulation frequency can lead to a phenomenon called summation, where individual action potentials merge together or "sum" to produce a larger response. This allows for greater depolarization of the membrane potential, leading to more frequent firing of action potentials. As the stimulation frequency increases, the membrane may not return to its resting potential before receiving the next stimulus, resulting in a higher number of action potentials being generated.
In absolute refractory period, none of channels are reconfigured, so that second active potential cannot be generated no matter how large the stimulus current is applied to the neuron. In contrast, in relative refractory period, some but not all of channels are reconfigured, another action potential can be generated but only by a greater stimulus current thatn that originally needed.
The stimulus is the sudden loud sound, while the response is the action of jumping. This reaction is known as the startle response, which is a primitive survival instinct triggered by unexpected loud noises.
action potential
A stronger stimulus is communicated to the next cell in the neural pathway by increasing the frequency of action potentials generated by the neuron. A stronger stimulus will trigger action potentials to occur more frequently, which results in a higher frequency of signals being transmitted to the next cell.
The FREQUENCY of action potentials that are conducted into the central nervous system serves as the code for the strength of the stimulus. This frequency code is needed because the amplitude of action potentials is constatnt (all or none). Acting through changes in action potential frequency, tonic receptors thus provide information about the relative intensity of a stimulus.
The all-or-none principle states that the properties of an action potential, such as amplitude and duration, are independent of the intensity of the stimulus that triggers it. This means that once a threshold stimulus is reached, the action potential will fire at maximal strength regardless of the strength of the initial stimulus.
Yes. ....Up to a point. There is a threshold the stimulus must surpass before creating a CAP (compound action potential). Anything below this threshold is called subthreshold. Once the stimulus is strong enough cause a CAP it is a stimulus threshold. At this point the CAP will continue to increase as the intensity of the stimulus increases (now termed suprathreshold) until a maximal stimulus causes a maximum response. Any stimulus stronger than the maximal stimulus is called a supramaximal and does not result in any larger a CAP than the maximum response caused by the maximal stimulus. source: http://www.unmc.edu/physiology/Mann/mann12.html
Increasing the stimulus voltage above the threshold value results in recruiting more nerve fibers to generate action potentials. This leads to a greater number of action potentials being generated simultaneously along the nerve, resulting in a larger compound action potential amplitude being recorded.
No, it doesn't become "larger" - the peak potential is always the same - it is a digital signal. Stronger stimulus will cause the nerve cell to fire more often - therefore stimulus strength is translated as action potential frequency.
If a cell were depolarized twice the normal amount needed to produce an action potential, it would still only produce a single action potential. The all-or-none principle states that once the threshold for an action potential is reached, the neuron will fire with a fixed amplitude and duration regardless of the strength of the stimulus.
Yes, this is due to the all or nothing law that neurons follow: "an excitable membrane either responds to a stimulus with a maximal action potential that spreads nondecrementally throughout the membrane, or it does not respond with an action potential at all." "
stimulus
Reaction
Supranormal Period (SNP) is the period during which a slightly smaller than normal stimulus can elicit a propagated response, although the amplitude of the action potential is reduced compared to normal. I'm not sure either as of to how the mechanism of this allows a stimulus lower than threshold can elicit this response.