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 3 characteristics of an action potential?An action potential has three phases: depolarization, overshoot, repolarization. There are two more states of the membrane potential related to the action potential. The first one is hypopolarization which precedes the depolarization, while the second one is hyperpolarization, which follows the repolarization.
What are the differences between graded potentials and action potentials?The main difference between graded potential and action potential is that graded potentials are the variable-strength signals that can be transmitted over short distances whereas action potentials are large depolarizations that can be transmitted over long distances.
What is the importance of graded potential?Output can be a pattern of action potentials, as in cells with axons, or a graded potential, as in amacrine neurons. The importance of these graded interactions is that they greatly increase the functional capacity of the nervous system.
Why are graded potentials called graded?Graded potential refers to the postsynaptic electrical impulse. These potentials are known as 'graded' because their size or amplitude is directly proportional to the strength of the triggering event.
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