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The term for making the inside of the membrane more positive is "depolarization." This process occurs when there is a change in the membrane potential, typically due to the influx of sodium ions (Na+) into the cell, reducing the negative internal charge relative to the outside. Depolarization is a key event in the generation of action potentials in neurons and muscle cells.
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Involves the influx of negative ions to depolarize the membrane?
This likely refers to the process of creating an action potential in a neuron. Negative ions, such as chloride or potassium, flow into the neuron to depolarize the cell membrane, making it more positive inside. This initiates the electrical signal that travels along the neuron.
Why don't the terms depolarization and action potential mean the same thing?
Depolarization occurs when a stimulus opens sodium channels which allow more sodium to go into the membrane making it less negative and more positive (toward reaching threshold). An action potential can only occur once the membrane reaches threshold which means it has reached the level needed through depolarization. An action potential is a brief reversal in polarity of the membrane making the inside more positive and the outside more negative, the reverse occurs again once the membrane reaches resting potential.
How does nerve fiber become depolarized?
A nerve fiber becomes polarized when the resting potential of the membrane changes. It starts out with an unequal distribution of charges- the outside is more positive and the inside is less positive. (Sodium (Na+) is in a higher concentration on the outside of the membrane and Potassium (K+) is in a lower concentration on the inside of the membrane.) A stimulus changes the gradient- when more Na+ flows in, the resting potential changes and polarization occurs, allowing for an action potential to be propagated down the axon.
How does the cell membrane become more positive outside and more negative inside?
The cell membrane is more positive outside due to a higher concentration of positively charged ions like sodium (Na+), while it is more negative inside due to a higher concentration of negatively charged ions like potassium (K+) and proteins. This creates an electrochemical gradient across the membrane, known as the membrane potential. This gradient is maintained by ion pumps and channels that selectively allow ions to move in and out of the cell, creating the different charges inside and outside.
What causes the inside of neuron becomes positive?
Outside a neuron, there are mostly sodium ions but some potassium ions. Inside the neuron, there are only potassium ions. Since both sodium and potassium are positive ions, and they are in a higher concentration outside the cell, that makes the outside have a more positive charge than the inside. But for all intents and purposes, the outside is positive, and the inside is negative. When the sodium ions (Na+) rush into the cell during depolarization, it causes the concentration of positive ions inside the cell to go WAY up, making the inside more positive than the outside. This means that the outside is now negative and the inside now positive.
What is the positive inside rule?
The positive inside rule is a general rule for membrane proteins. Because of the mechanism involved in transmembrane domain insertion (regions of the protein which cross the membrane), membrane proteins tend to have more residues which can take on a positive charge on the inside of their cells. So, almost all, if not all membrane proteins have more solvent exposed Lysine and Arginine residues on the sides of the transmembrane domains which rest inside of the cell in comparison to the number which rest on the outside of the cell.
The diffusion of K out of the cell makes the inside of the cell less positive or more negative and acts to restore the original resting membrane potential This process is called?
This process is called hyperpolarization. Hyperpolarization occurs when the movement of positive ions out of the cell causes the inside of the cell to become more negative, making it further from the threshold for firing an action potential. By restoring the original resting membrane potential, hyperpolarization helps to regulate neuronal activity and maintain the cell's excitability.
Involves the influx of negative ions to depolarize the membrane?
This likely refers to the process of creating an action potential in a neuron. Negative ions, such as chloride or potassium, flow into the neuron to depolarize the cell membrane, making it more positive inside. This initiates the electrical signal that travels along the neuron.
Which ion is responsible for hyperpolarization?
Potassium ions are responsible for hyperpolarization by exiting the cell, making the inside more negative than the resting membrane potential. This efflux of positive ions causes the cell to become more negative than its resting state, increasing the membrane potential and inhibiting action potential generation.
If a resting potential becomes more negative what happens to the cell?
When the membrane potential becomes more negative it is being hyperpolarized. Remember the resting membrane potential is already at a negative state (~70mV). So if you are making a comparison of a membrane potential that is hyperpolarized in comparison to a resting membrane potential, the resting membrane potential is said to be more depolarized.When the membrane potential becomes more positive it is called depolarization.
Why don't the terms depolarization and action potential mean the same thing?
Depolarization occurs when a stimulus opens sodium channels which allow more sodium to go into the membrane making it less negative and more positive (toward reaching threshold). An action potential can only occur once the membrane reaches threshold which means it has reached the level needed through depolarization. An action potential is a brief reversal in polarity of the membrane making the inside more positive and the outside more negative, the reverse occurs again once the membrane reaches resting potential.
How does nerve fiber become depolarized?
A nerve fiber becomes polarized when the resting potential of the membrane changes. It starts out with an unequal distribution of charges- the outside is more positive and the inside is less positive. (Sodium (Na+) is in a higher concentration on the outside of the membrane and Potassium (K+) is in a lower concentration on the inside of the membrane.) A stimulus changes the gradient- when more Na+ flows in, the resting potential changes and polarization occurs, allowing for an action potential to be propagated down the axon.
How does the cell membrane become more positive outside and more negative inside?
The cell membrane is more positive outside due to a higher concentration of positively charged ions like sodium (Na+), while it is more negative inside due to a higher concentration of negatively charged ions like potassium (K+) and proteins. This creates an electrochemical gradient across the membrane, known as the membrane potential. This gradient is maintained by ion pumps and channels that selectively allow ions to move in and out of the cell, creating the different charges inside and outside.
What causes the inside of neuron becomes positive?
Outside a neuron, there are mostly sodium ions but some potassium ions. Inside the neuron, there are only potassium ions. Since both sodium and potassium are positive ions, and they are in a higher concentration outside the cell, that makes the outside have a more positive charge than the inside. But for all intents and purposes, the outside is positive, and the inside is negative. When the sodium ions (Na+) rush into the cell during depolarization, it causes the concentration of positive ions inside the cell to go WAY up, making the inside more positive than the outside. This means that the outside is now negative and the inside now positive.
What is a reduction in membrane potential called?
A reduction in membrane potential is called hyperpolarization. This occurs when the inside of the cell becomes more negative than the outside, making it less likely for the cell to generate an action potential.
When ACh receptors open what ion causes depolarization of the postsynaptic membrane?
When acetylcholine (ACh) receptors open, sodium ions (Na+) primarily flow into the postsynaptic membrane. This influx of positively charged sodium ions leads to depolarization, making the inside of the cell more positive. If the depolarization reaches a certain threshold, it can trigger an action potential in the postsynaptic neuron.
Compared to the inside of the resting plasma membrane the outside surface of the membrane is?
The outside surface of the plasma membrane is typically more exposed to the extracellular environment and contains different types of molecules, such as cell surface receptors and glycoproteins involved in cell signaling and recognition. In contrast, the inside surface is more involved in intracellular interactions and contains various types of proteins that regulate cell functions, like ion channels and transporters.
