Resting Potential, Graded Potential, Action Potential
Neurons get information from DENDRITES and CELL BODY
- They are connected to a lot of other neurons
- Based on summation of that information, neurotransmitters will either fire an
action potential or not.
Three types of potentials:
- Resting Potential:
o Resting potential of a neuron at rest
- Graded Potential:
o Based on stimulus potential neuron is going to get
- Action Potential:
o Can lead to synaptic activity on the next neuron
Resting Membrane Potential
Cell Membranes – composed of a phospholipid bilayer:
- Hydrophobic tail
- Hydrophilic head
In an aqueous environment, lipids arrange themselves in a double layer so that tails
are “inside” away from aqueous environment and heads are facing out, towards the
EXTRACELLULAR and INTRACELLULAR environments.
, Key Terms:
Cation – positively charged ion
- K+, Ca++, Na+
Anion – negatively charged ion
- Proteins-, Cl-, PO4-3
Electrical Gradient – gradients based on charge
Chemical Gradient – gradients based on concentration
Ions that play a major role in resting membrane potential includes, K+ and Na+
- Concentration of Na+ is higher in the EXTRACELLULAR region of the cell
- Concentration of K+ is higher in the INTRACELLULAR region of the cell
There are anions in both the extra- and intracellular regions of the cell, these usually
have a minimal effect,
- Except for the LARGE PROTEINS, which are negatively charged
Cell membranes are polarized (charged)
What causes cell membranes to be charged?
All cell membranes have a slight voltage or potential difference across their expands.
- Extracellular – slightly positive
- Intracellular – slightly negative
o Caused by the selective diffusion of the ions across the membrane
Transmembrane protein – CHANNEL PROTEIN – only allow one type of particle to
diffuse through them
- We are interested in the K+ and Na+ Channels
o These channels allow charged ions to move along their concentration
gradients through FACILITATED DIFFUSION
Neurons get information from DENDRITES and CELL BODY
- They are connected to a lot of other neurons
- Based on summation of that information, neurotransmitters will either fire an
action potential or not.
Three types of potentials:
- Resting Potential:
o Resting potential of a neuron at rest
- Graded Potential:
o Based on stimulus potential neuron is going to get
- Action Potential:
o Can lead to synaptic activity on the next neuron
Resting Membrane Potential
Cell Membranes – composed of a phospholipid bilayer:
- Hydrophobic tail
- Hydrophilic head
In an aqueous environment, lipids arrange themselves in a double layer so that tails
are “inside” away from aqueous environment and heads are facing out, towards the
EXTRACELLULAR and INTRACELLULAR environments.
, Key Terms:
Cation – positively charged ion
- K+, Ca++, Na+
Anion – negatively charged ion
- Proteins-, Cl-, PO4-3
Electrical Gradient – gradients based on charge
Chemical Gradient – gradients based on concentration
Ions that play a major role in resting membrane potential includes, K+ and Na+
- Concentration of Na+ is higher in the EXTRACELLULAR region of the cell
- Concentration of K+ is higher in the INTRACELLULAR region of the cell
There are anions in both the extra- and intracellular regions of the cell, these usually
have a minimal effect,
- Except for the LARGE PROTEINS, which are negatively charged
Cell membranes are polarized (charged)
What causes cell membranes to be charged?
All cell membranes have a slight voltage or potential difference across their expands.
- Extracellular – slightly positive
- Intracellular – slightly negative
o Caused by the selective diffusion of the ions across the membrane
Transmembrane protein – CHANNEL PROTEIN – only allow one type of particle to
diffuse through them
- We are interested in the K+ and Na+ Channels
o These channels allow charged ions to move along their concentration
gradients through FACILITATED DIFFUSION
