graded potentials are generated in nerve cells in axons.
graded potentials are generated in nerve cells in axons.
where are graded potentials generated in nerve cells?
axons
graded potentials are changes in membrane potential that vary in size, as opposed to being all-or-none. they include diverse potentials such as receptor potentials, electrotonic potentials, subthreshold membrane potential oscillations, slow-wave potential, pacemaker potentials, and synaptic potentials, which scale with the magnitude of the stimulus. they arise from the summation of the individual actions of ligand-gated ion channel proteins, and decrease over time and space. they do not typically involve voltage-gated sodium and potassium channels. these impulses are incremental and may be excitatory or inhibitory. they occur at the postsynaptic dendrite in response to presynaptic neuron firing and release of neurotransmitter, or may occur in skeletal, smooth, or cardiac muscle in response to nerve input. the magnitude of a graded potential is determined by the strength of the stimulus.
graded potential
one prominent characteristic of many neurons is excitability. neurons generate electrical impulses or changes in voltage of two types: graded potentials and action potentials. graded potentials occur when the membrane potential depolarizes and hyperpolarizes in a graded fashion relative to the amount of stimulus that is applied to the neuron. an action potential on the other hand is an all-or-none electrical impulse. despite being slower than graded potentials, action potentials have the advantage of traveling long distances in axons with little or no decrement. much of the current knowledge of action potentials comes from squid axon experiments by sir alan lloyd hodgkin and sir andrew huxley.
cellular neuroscience