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What effect does the opening of the potassium channels have on the charge difference across the neuron's membrane?
Wiki User
∙ 13y ago
repolarization
Wiki User
∙ 13y ago
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Is the membrane of neurons very permeable to Na when at rest?
the same as that to potassium
What changes occur in the neuron?
Neurons undergo depolarization and repolarization when stimulated. The sodium and potassium channels open.
What part of a neuron would probably be affected most by the application of Novocain?
Novocain blocks calcium channels. Voltage-dependent calcium channels are a group of ion channels found in the membrane of excitable cells such as the axons of neurons and glial cells.
How does tetraethylammonium affect the restig membrane potential?
Tetrodotoxin (TTX) completely prevents action potentials from generating peripherally. This can be fatal because it causes muscle paralysis, including those responsible for respiration. The way TTX does this is by blocking sodium channels, thereby preventing sodium ions from entering the cell, which in turn prevents membrane depolarisation.
Why causes the neurons fire?
Neurons are nerve cells, and they fire to relay messages from neuron to neuron. Neurons fire when a charge jumps across a synapse to the dendrite of a cell. The neuron then fires the charge down it's axon, and the charge travels to the next neuron.
What effect does the leaking of potassium across the membrane have on the membrane potential of Kevin's neurons?
It makes the inside of the neurons more negative.
Is the membrane of neurons very permeable to Na when at rest?
the same as that to potassium
What type of channels that are present within the varicosities of autonomic neurons are absent from the axon terminal of other neurons?
Voltage-gated Sodium ions and Potassium ions channels
What changes occur in the neuron?
Neurons undergo depolarization and repolarization when stimulated. The sodium and potassium channels open.
Does the sodium or potassium pump provide energy for neurons but does not affect resting membrane potential?
False
What conducts local currents towards the soma?
Dendrites receive stimuli from other neurons. Charge is carried by ions. The direction of the charge flows in is determined by the electrochemical potential difference across the membrane and the properties of membrane ion channels.
What part of a neuron would probably be affected most by the application of Novocain?
Novocain blocks calcium channels. Voltage-dependent calcium channels are a group of ion channels found in the membrane of excitable cells such as the axons of neurons and glial cells.
How does tetraethylammonium affect the restig membrane potential?
Tetrodotoxin (TTX) completely prevents action potentials from generating peripherally. This can be fatal because it causes muscle paralysis, including those responsible for respiration. The way TTX does this is by blocking sodium channels, thereby preventing sodium ions from entering the cell, which in turn prevents membrane depolarisation.
Why causes the neurons fire?
Neurons are nerve cells, and they fire to relay messages from neuron to neuron. Neurons fire when a charge jumps across a synapse to the dendrite of a cell. The neuron then fires the charge down it's axon, and the charge travels to the next neuron.
When does a neuron exhibit resting potential?
The human nervous system consists of billions of nerve cells (or neurons)plus supporting (neuroglial) cells. Neurons are able to respond to stimuli (such as touch, sound, light, and so on), conduct impulses, and communicate with each other (and with other types of cells like muscle cells). Neurons can respond to stimuli and conduct impulses because a membrane potential is established across the cell membrane. In other words, there is an unequal distribution of ions (charged atoms) on the two sides of a nerve cell membrane. The membranes of all nerve cells have a potential difference across them, with the cell interior negative with respect to the exterior (a). In neurons, stimuli can alter this potential difference by opening sodium channels in the membrane. For example, neurotransmitters interact specifically with sodium channels (or gates). So sodium ions flow into the cell, reducing the voltage across the membrane. Once the potential difference reaches a threshold voltage, the reduced voltage causes hundreds of sodium gates in that region of the membrane to open briefly. Sodium ions flood into the cell, completely depolarizing the membrane (b). This opens more voltage-gated ion channels in the adjacent membrane, and so a wave of depolarization courses along the cell - the action potential. As the action potential nears its peak, the sodium gates close, and potassium gates open, allowing ions to flow out of the cell to restore the normal potential of the membrane. Membranes are polarized or, in other words, exhibit a RESTING MEMBRANE POTENTIAL. This means that there is an unequal distribution of ions (atoms with a positive or negative charge) on the two sides of the nerve cell membrane. This POTENTIAL generally measures about 70 millivolts (with the INSIDE of the membrane negative with respect to the outside). So, the RESTING MEMBRANE POTENTIAL is expressed as -70 mV, and the minus means that the inside is negative relative to (or compared to) the outside. It is called a RESTING potential because it occurs when a membrane is not being stimulated or conducting impulses (in other words, it's resting). Source : Internet.
Do the neurons contain mitochondria?
Yes. Neurons need to contain mitochondria in order to produce enough ATP molecules to open and close the sodium/potassium channels at the axon. It also needs ATP to undergo exocytosis and endocytosis which forms vesicles containing neurotransmitters.
What is the hyperpolarization that occurs after repolarizing phase of action potential?
Hyperpolarization occurs because some of the K+ channels remain open to allow the Na+ channels to reset. This excessive amount of K+ causes hyperpolarization so the Na+ channels open to bring the potential back up to threshold.
