The neurone has a resting potential when
it is not transmitting a nerve impulse
The energy of the stimulus triggers some
of the sodium voltage gated ion channels
to open making the membrane more
permeable to sodium ions. Sodium ions
can therefore diffuse across the neuronal
membrane into the axon
The change in charge causes more sodium
ion channels to open
Potassium ions now diffuse out of the
axon. This reduces the charge, resulting in
the inside of the axon becoming more
negative than the outside
Initially, lots of potassium ions diffuse out
of the axon resulting in the inside of the
axon becoming more negative than in its
resting state. This is known as
hyperpolarisation. The voltage gated
potassium channels now close.
Sodium – Potassium pumps cause sodium
ions to move out of the cell and potassium
ions to move in. The axon returns to its
resting potential
When the potential difference reaches
+40mV, the sodium ion channels close and
the potassium channels open. This makes
the membrane now impermeable to
sodium ions and permeable to potassium
ions.
The neurone has a resting potential when
it is not transmitting a nerve impulse
The energy of the stimulus triggers some
of the sodium voltage gated ion channels
to open making the membrane more
permeable to sodium ions. Sodium ions
can therefore diffuse across the neuronal
membrane into the axon
The change in charge causes more sodium
ion channels to open
When the potential difference reaches
+40mV, the sodium ion channels close and
the potassium channels open. This makes
the membrane now impermeable to
sodium ions and permeable to potassium
ions.
Potassium ions now diffuse out of the
axon. This reduces the charge, resulting in
the inside of the axon becoming more
negative than the outside
Initially, lots of potassium ions diffuse out
of the axon resulting in the inside of the
axon becoming more negative than in its
resting state. This is known as
hyperpolarisation. The voltage gated
potassium channels now close.
Sodium – Potassium pumps cause sodium
ions to move out of the cell and potassium
ions to move in. The axon returns to its
resting potential