Neuron: Difference between revisions

Line 20:

Once an action potential has been established, it “moves” along the axon in a neuron. The action potential does not move in a physical sense of the word; the reversal of electrical charge is instead reproduced at different points along the axon in a “Mexican wave” effect. One point in an axon will become depolarised (depolarisation is a change in a cell’s membrane potential, making it more positive or less negative), and this depolarisation is a stimulus for the next region of the axon to depolarise. As the next region depolarises, the previous region returns to normal and repolarises.

Eventually, the action potential will reach the end of an axon, known as a synaptic knob.

When an action potential has passed, the cell restores the resting potential of -65mV through two transmembrane proteins: voltage gated potassium channels, and Na+/K+ ATPase (sodium/potassium pump). The potassium channels are voltage sensitive and open when an action potential occurs and peaks, they open while the Sodium channels become inactive at peak voltage. This drives the cell back to resting potential, and also ensures there is a refractory period after each action potential, because the sodium channels must go from their closed (high voltage) conformation to inactive (low voltage) before they can be opened again with proper depolarization. The sodium-potassium pump uses energy to actively, constantly pump sodium out of and potassium into the cell - the image on the right has the right idea, however, it has the directions backwards. [Someone capable please edit and fix the image]

==Action upon other neurons==

@@ Line 20: / Line 20: @@
 Once an action potential has been established, it “moves” along the axon in a neuron. The action potential does not move in a physical sense of the word; the reversal of electrical charge is instead reproduced at different points along the axon in a “Mexican wave” effect. One point in an axon will become depolarised (depolarisation is a change in a cell’s membrane potential, making it more positive or less negative), and this depolarisation is a stimulus for the next region of the axon to depolarise. As the next region depolarises, the previous region returns to normal and repolarises.
 Eventually, the action potential will reach the end of an axon, known as a synaptic knob.
+When an action potential has passed, the cell restores the resting potential of -65mV through two transmembrane proteins: voltage gated potassium channels, and Na+/K+ ATPase (sodium/potassium pump). The potassium channels are voltage sensitive and open when an action potential occurs and peaks, they open while the Sodium channels become inactive at peak voltage. This drives the cell back to resting potential, and also ensures there is a refractory period after each action potential, because the sodium channels must go from their closed (high voltage) conformation to inactive (low voltage) before they can be opened again with proper depolarization. The sodium-potassium pump uses energy to actively, constantly pump sodium out of and potassium into the cell - the image on the right has the right idea, however, it has the directions backwards. [Someone capable please edit and fix the image]
 ==Action upon other neurons==