lOMoARcPSD|18482020
Psyo 1011 - Sept. 18th - Lecture notes 4
Intro to Psyo & Nesc I (Dalhousie University)
Studocu is not sponsored or endorsed by any college or university
Downloaded by Abdel Ghanem ()
, lOMoARcPSD|18482020
Sept. 18th
Ions move across the membrane through channels because of 2
different physical forces, electrical forces and osmotic forces.
Both these forces act on the ions inside and outside of the
neuron.
The electrical force pushes potassium in and the chemical force
pushes it out and since the chemical/ osmotic force is stronger,
the net force is out of the cell.
The equilibrium potential is the membrane potential at which the
electrical and osmotic/chemical forces are balanced and there’s
no net flow of ions across the membrane.
It can be used to find which direction the ion is going to move and
to know what’s going to happen as soon as the channel opens.
The equilibrium potential for sodium is +65mV
The resting potential should shift to the equilibrium potential for
the movement of ions to stop and the net movement becomes
zero.
The concentration of K+ outside a typical neuron is reduced by ½.
The K+ ions will move outside the cell. This makes the equilibrium
potential more negative as the osmotic force becomes stronger.
When you open the channel for a particular ion, the resting
potential will move towards the equilibrium potential of that
particular ion.
If the concentration of K+ outside the cell is more, the osmotic
force will be weaker so the equilibrium potential will be more
positive.
Downloaded by Abdel Ghanem ()
Psyo 1011 - Sept. 18th - Lecture notes 4
Intro to Psyo & Nesc I (Dalhousie University)
Studocu is not sponsored or endorsed by any college or university
Downloaded by Abdel Ghanem ()
, lOMoARcPSD|18482020
Sept. 18th
Ions move across the membrane through channels because of 2
different physical forces, electrical forces and osmotic forces.
Both these forces act on the ions inside and outside of the
neuron.
The electrical force pushes potassium in and the chemical force
pushes it out and since the chemical/ osmotic force is stronger,
the net force is out of the cell.
The equilibrium potential is the membrane potential at which the
electrical and osmotic/chemical forces are balanced and there’s
no net flow of ions across the membrane.
It can be used to find which direction the ion is going to move and
to know what’s going to happen as soon as the channel opens.
The equilibrium potential for sodium is +65mV
The resting potential should shift to the equilibrium potential for
the movement of ions to stop and the net movement becomes
zero.
The concentration of K+ outside a typical neuron is reduced by ½.
The K+ ions will move outside the cell. This makes the equilibrium
potential more negative as the osmotic force becomes stronger.
When you open the channel for a particular ion, the resting
potential will move towards the equilibrium potential of that
particular ion.
If the concentration of K+ outside the cell is more, the osmotic
force will be weaker so the equilibrium potential will be more
positive.
Downloaded by Abdel Ghanem ()
