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The period of time after the initiation of one action potentialwhen it is impossible to initiate SECOND ACTION POTENTIAL NO MATTER how much the cell is depolarized is called?
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A neuron has an altered charge potential?
Depolarized
Does a neuron become depolarized during an inhibitory postsynaptic potential?
False
What potentials are short-livedlocal changes in membrane potential that can be either depolarized or hyperpolarized?
Graded Potentials
Does action potentials occur at nodes?
yes, the action potential occurs at the nodes of Ranvier -- there are Na (sodium channels) there that are depolarized/opened to maintain the action potential.
Which is greater - The extent of membrane polarization at threshold potential or that of the resting membrane potential?
A cell is more depolarized at it's threshold potential than it is at it's resting potential. This is important because a nervous system where a random excitatory post synaptic potential (epsp) would trigger the next neuron would lead to an overly excitable nervous system (btw, this is why caffeine makes you jittery).
A neuron has an altered charge potential?
Depolarized
Does a neuron become depolarized during an inhibitory postsynaptic potential?
False
What potentials are short-livedlocal changes in membrane potential that can be either depolarized or hyperpolarized?
Graded Potentials
When a neuron is depolarized to threshold?
1. The neuron fires an action potential, sending the electrical signal down the axon.
Does action potentials occur at nodes?
yes, the action potential occurs at the nodes of Ranvier -- there are Na (sodium channels) there that are depolarized/opened to maintain the action potential.
What was Excitation and Inhibition about?
Excitation and Inhibition occur in the neurons. Excitation is when a neuron becomes depolarized and fires an action potential. Inhibition is when a neuron becomes hyperpolarized preventing it from firing an action potential.
Which is greater - The extent of membrane polarization at threshold potential or that of the resting membrane potential?
A cell is more depolarized at it's threshold potential than it is at it's resting potential. This is important because a nervous system where a random excitatory post synaptic potential (epsp) would trigger the next neuron would lead to an overly excitable nervous system (btw, this is why caffeine makes you jittery).
According to the all or none principle what would happen if a cell were depolarized twice the normal amount needed to produce an action potential?
The strength of the an action potential would increase. This would happen because it would need twice as much energy before being produced.
What happens when a neuron is polarized?
When a neuron is polarized, usually by the influx of chloride ions into the neuron, it is incapable of creating an action potential (incapable of firing). Only when the neuron returns to a resting potential, via pumping ions back across the membrane, can it be depolarized (sodium ion influx) to generate an action potential.
What is the difference between local potential and action potential?
Local Potentials: Ligand regulated, may be depolarizing or hyperpolarizing, reversible, local, decremental Action Potentials: Voltage regulated, begins with depolarization, irreversible, self-propagating, nondecremental.
What is involved in action potential?
also known as the "nerve impulse". with stimulus the permeability of the membrane to NA+ at the point of stimulation increase, and NA- ions rush into the cell causing the outside to lose its excess of positive ions. That location becomes depolarized only for an instant, and this produces an action potential.
When can a second nerve impulse cannot be generated?
The generation of a second action in some neurons can only happen after a refractory period, when the membrane potential has returned it's base level or even more negative. This is because some types of Na+ channels inactivate at a positive potential and then require a negative potential to reset. Other neurons have other types of channels and can fire multiple action potentials to a single depolarization.
