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Distribution of Ions In Resting Axons

  • The ion concentrations in the extracellular fluid (ECF) and intracellular fluid (ICF) of a resting axon can be image descriptionmeasured.
An image showing the distribution of ions between extracellular and intracellular fluid in resting axons
An image showing the (Na, K, Cl and proteins) concentration in resting axon
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These concentrations are often expressed in millimolar (mM) units.

Molarity:

An image to explain the molarity concept

  • Molarity (M) is the number of moles of a solute in one liter of solution.
  • One Mole of a solute contains 6.023 x 1023 particles.
  • Thus, a 1 molar (M) solution contains 6.023 x 1023 particles in a liter of solution.
  • A 1 millimolar (mM) solution is 1000 X less concentrated than a 1 M solution.

 

  • These measurements show that image descriptionNa+ (sodium) and image descriptionCl- (chloride) are concentrated in the ECF.
An image showing the (Na, K, Cl and proteins) concentration in resting axon
An image showing the Na (ECF) and other ions distribution of ions between extracellular and intracellular fluid in resting axons
An image showing the Cl (ECF), Na (ECF) and other ions distribution of ions between extracellular and intracellular fluid in resting axons
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  • In contrast, image descriptionK+ (potassium) and image descriptionproteins- (organic anions) are concentrated in the ICF.
An image showing the Cl (ECF), Na (ECF) and other ions distribution of ions between extracellular and intracellular fluid in resting axons
An image showing the K(ICF), Cl (ECF), Na (ECF) and other ions distribution of ions between extracellular and intracellular fluid in resting axons
An image showing the Proteins(ICF), K(ICF), Cl (ECF), Na (ECF) and other ions distribution of ions between extracellular and intracellular fluid in resting axons
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