Neuronal Action Potential - Show There are important differences between graded potentials and action potentials of neurons (see Introduction to this lecture). Table 1 lists the main differences between graded potentials and action potentials. As discussed in this lecture and upcoming lectures, most of these differences are due to the fact that graded potentials result from the passive electrical property of the neuronal membrane, whereas action potentials result from an orchestrated response to depolarizing stimuli, and involve a coordinated activity of voltage-gated ion channels. Graded potentials must occur to depolarize the neuron to threshold before action potentials can occur. Depending on the cell and type and the nature of stimulus, graded potentials that lead to action potentials are called synaptic potentials (i.e., post-synaptic potential changes in neurons), generator potentials or receptor potentials (graded potentials in sensory cells causes by adequate stimuli), or end-plate potentials (i.e., synaptic potentials in skeletal muscle cells). These graded potentials will be discussed in later lectures. In the next lecture, we will consider the propagation of neuronal action potentials and we will see that additional neuronal adaptations allow action potentials to travel over long distances without losing any strength (i.e., amplitude). In yet another later lecture, we will see how summation of graded potentials is responsible for much of information processing at specialized contact regions between neurons (synapses). Table 1. Features of graded potentials and action potentials
Note: The details of action potentials noted here refer to those of neuronal action potentials. As we will see throughout our study of physiology, other action potentials (for example, in skeletal, cardiac, and smooth myocytes, and in some endocrine cells) exhibit different features than those mentioned here. Posted: Thursday, July 5, 2012 What are two major differences between graded and action potentials?Graded potentials occur in dendrites, cell bodies and sensory receptors. Graded potentials dissipate with distance from stimulus. On the other hand, action potentials occur when graded potentials reach the axon hillock at a certain level of depolarisation (around -55mV).
How do action potentials and graded potentials differ quizlet?Graded potentials can result from the opening of chemically gated channels; action potentials require the opening of voltage-gated channels. Graded potentials occur along dendrites, whereas action potentials occur along axons.
What is the correct relationship between graded potentials and action potentials quizlet?An action potential is a rapid change in the membrane potential of an excitable cell as a result of opening and closing of voltage gated ion channels. A graded potential varies in magnitude and duration, while an action potential remains the same in a given cell.
|