6.5.5
Explain how a nerve impulse passes
along a non-myelinated neuron
NERVE IMPULSE
• An electrical current which carry information
that travels along dendrites and axons of a
neuron
NON-MYELINATED NEURON
• Neuron without myelin sheath
RESTING POTENTIAL
• The potential difference across a nerve cell membrane
when it is not stimulated. (-70mV)
• A nerve imp...
• When the neuron is not sending an impulse,
the charge difference is maintained inside and
outside of the axon cell. This...
• The resting potential is due to the active
transport of Na+ ions and K + ions through
sodium-potassium pumps.
• The pump...
ACTION POTENTIAL
• The potential difference produced across the
plasma membrane of nerve cell when it is
stimulated.

• Du...
• Action potential is triggered by a stimulus
received at a receptor or sensitive nerve ending
causes a sodium channel to ...
• This area of axon then initiates the next area
of the axon to open up the other sodium
channels. (Domino effect)
• There...
• This causes the rapid flow of K + ions out of the
membrane and thus, “repolarizing” the
membrane.
• So, the inside is ag...
IB BIOLOGY 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron
IB BIOLOGY 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron
IB BIOLOGY 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron
IB BIOLOGY 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron
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IB BIOLOGY 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron

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6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron

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IB BIOLOGY 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron

  1. 1. 6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron
  2. 2. NERVE IMPULSE • An electrical current which carry information that travels along dendrites and axons of a neuron
  3. 3. NON-MYELINATED NEURON • Neuron without myelin sheath
  4. 4. RESTING POTENTIAL • The potential difference across a nerve cell membrane when it is not stimulated. (-70mV) • A nerve impulse is an electrical current that travels along dendrites or axons due to ions moving through voltage-gated channels in the neuron’s plasma membrane. • The voltage-gated channels are the sodium and potassium channels, which means that they can open and close depending on the voltage across the membrane.
  5. 5. • When the neuron is not sending an impulse, the charge difference is maintained inside and outside of the axon cell. This is called the resting potential where it is polarized.
  6. 6. • The resting potential is due to the active transport of Na+ ions and K + ions through sodium-potassium pumps. • The pumps sends Na+ ions out of the axon cell and brings K + ions in. • There are negatively charged ions (Cl-) located permanently in the cytoplasm of the axon. This leads to the net positive charge outside the axon membrane and a net negative charge inside the axon membrane.
  7. 7. ACTION POTENTIAL • The potential difference produced across the plasma membrane of nerve cell when it is stimulated. • Due to the diffusion of ions from outside the axon to the inside and from the inside of axon to the outside.
  8. 8. • Action potential is triggered by a stimulus received at a receptor or sensitive nerve ending causes a sodium channel to open. • The Na+ ions which is actively transported out diffused into the membrane. This causes the local region inside the membrane to have net positive charge while the outside having net negative charge. • The membrane is said to be “depolarized”. The resting potential is reversed from -70mV to +40mV. ~
  9. 9. • This area of axon then initiates the next area of the axon to open up the other sodium channels. (Domino effect) • Therefore, the moving depolarization is called an action potential. • After a short while, the sodium channels closed, and the potassium channels are opened.
  10. 10. • This causes the rapid flow of K + ions out of the membrane and thus, “repolarizing” the membrane. • So, the inside is again negatively charged and the outside is positively charged. • The resting potential of the membrane is restored.

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