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Ion Channel Proteins

  • The phospholipid bilayer forms a barrier that limits the passage of ions through the neuron cell membrane and separates the surrounding water environment into two compartments, the image descriptionextracellular fluid (ECF) and image descriptionintracellular fluid (ICF).
An image showing the neuron cell membrane in addition to ion channels (gated and leak) and the proteins inside
An image showing the ECF (Extracellular fluid) with neuron cell membrane in addition to ion channels (gated and leak) and the proteins inside
An image showing the ICF (Intracellular fluid) and ECF (Extracellular fluid) with neuron cell membrane in addition to ion channels (gated and leak) and the proteins inside
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  • image descriptionIon channels are transmembrane proteins that allow small ions to move between the ECF and ICF without binding or using cellular energy.
An image showing the ICF (Intracellular fluid) and ECF (Extracellular fluid) with neuron cell membrane in addition to ion channels (gated and leak) and the proteins inside
An image showing the ion channels (gated and leak) [Labeled], ICF (Intracellular fluid) and ECF (Extracellular fluid) with neuron cell membrane and the proteins inside
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  • The size, shape, and charge of each channel’s pore selectively allows only¬†certain types of ions to pass.
  • Some types of channels are functionally open most of the time and continually allow image descriptionions to diffuse through the selective pore.
  • K+ leak channels (in nerve and muscle cells) are examples. They allow K+ to flow out of the cell, which plays a major role in establishing resting membrane potentials.
  • Other types of membrane channels have image descriptiongates that usually block the flow of ions unless certain stimuli (chemical, voltage, mechanical, etc) are present.
An image showing the ICF (Intracellular fluid) and ECF (Extracellular fluid) with neuron cell membrane in addition to ion channels (gated and leak) and the proteins inside
An image showing the ICF (Intracellular fluid) and ECF (Extracellular fluid) with neuron cell membrane in addition to ion channels (gated and leak) and the proteins inside
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  • When stimulated, the channel gates open and image descriptionions diffuse through the selective pore.
  • Na+ and K+ voltage-gated channels (also in nerve and muscle cells) are examples. A change in voltage causes these channels to open and the exchange of ions produces an action potential (or impulse).