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Why does increasing extracellular potassium ion cause membrane potential to change to a less negative value?
Wiki User
∙ 11y ago
the membrane potential became less negative because less potassium ions went out of the cell (since the extra cellular space has higher concentration of potassium, and potassium goes down its concentration gradient, from high concentration to low concentration). since less potassium (K+)which is positive, left the cell more it became more positive (less negative)
Wiki User
∙ 11y ago
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Through the membrane of a resting neuron highly permeable to potassium ions its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is?
Slightly permeable to sodium ions.
Why is there a resting membrane potential across the cell membrane?
sodium/potassium pump
What Hyperpolarizing membrane potential occurs in the postsynaptic membrane of a synapse?
Hyperpolarization means that the membrane potential becames more negative than the resting potential. This means that it is more difficult for an action potential to be triggered at the postsynaptic membrane. This occurs at inhibitory synapses. Hyperpolarization can be achieved by increasing the permeability of the membrane to potassium or chloride ions. If potassium permeability is increased more potassium ions will leave the cell, down their concentration gradient; if chloride permeability increases chloride ions will enter the cell down their concentration gradient. Both movements will make the inside of the cell more negative ie they will cause hyperpolarization.
The role of the sodium potassium pump in maintaining a cells resting membrane potential?
The relative concentration of sodium (Na+) and potassium (K+) in the neuron with respect to their concentration in the extracellular space is what causes the electrical potential and the differential concentration is established by a Na-K Atpase which exudes sodium and transports potassium into the neuron.
What would happen to a resting membrane potential if the sodium potassium transport pump was blocked?
During depolarization, sodium (Na) rushes into the neuron through Na channels (at the Nodes of Ranvier between the bundles of myelin "insulation"). Less Na in the extracellular fluid would mean there would be less to rush in. So, the neuron would not be depolarized as well. The resting membrane potential would be more positive on the inside.
The membrane-bound enzyme system that restores and maintains the resting membrane potential is what pump?
sodium-potassium
What affect does elevated extracellular chloride have on the resting membrane potential of a neuron?
Not much. Changing the extracellular chloride changes the level inside the cell so they will be in equilibrium again. The chloride ion plays little role in resting potential.
Potassium channels open late in the action potential to cause membrane?
...repolarization
Why is the resting potential value of a membrane negative?
The resting membrane potential is the difference between the inside of the cell relative to the outside. The outside is always taken as 0mv. The resting membrane potential is negative because there is a higher concentration of potassium ions outside the cell (because the membrane is more permeable to potassium ions) than inside. Since potassium ions are positively charged this leads to a negative value.
What will happen to a person's resting membrane potential if they take potassium enhanced intravenous solution?
A potassium enhanced intravenous solution would increase the concentration of potassium ions in the brain. Since potassium ions are positively charged, they depolarize the resting membrane potential. For example, a resting membrane potential of -65 millivolts would be depolarized to -62 millivolts. An appropriate concentration could lead to a significant depolarization of, say, -60 millivolts, at which point an action potential could be possible.
What is the Difference between membrane potential and equilibrium potential?
Equilibrium potential is referring to the equilibrium (or balance) established between the forces of diffusion and electrical forces specific to each ion. For example, the equilibrium potential for Potassium, K+, in a cell with a semi permeable membrane is -80mV or Ek+=80mV. The membrane potential, on the other hand, refers to the voltage across the membrane at anytime and takes into account a range of equilibrium potentials such as Potassium, Sodium etc.
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.
