Lecture 2
The Em for a RBC isn't -20mV
The outside of a cell is always negative with respect to the outside
The inside of a cell is always negative with respect to the outside
The Em for a neuron isn't -70mV
A high level of Cl- entering the cell
Active transport of ions across a membrane
An unequal distribution of ions across a selectively permeable membrane
Electrogenicity of NaK-ATP-ase
Diffuses into the cell
Diffuses out of the cell
Diffuses into the cell
Diffuses out of the cell
Diffuses into the cell
Diffuses out of the cell
Diffuses into the cell
Diffuses out of the cell
The Vm becomes more positive than the resting potential
The Vm becomes more negative than the resting potential
The Vm moves back to the resting potential following depolarisation
The Vm remains constant
The Vm becomes more positive than the resting potential
The Vm becomes more negative than the resting potential
The Vm moves back to the resting potential following depolarisation
The Vm remains constant
The Vm becomes more positive than the resting potential
The Vm becomes more negative than the resting potential
The Vm moves back to the resting potential following depolarisation
The Vm remains constant
Serve as short distance signals
Are 'all or nothing'
Serve as long distance signals
Do not act in muscles (end plate potentials)
The change in voltage in a graded potential is greatest underneath a synapse
The signal of a graded potential is decromental
The larger the initial active area, the larger the decromental spread
The signal of a graded potential is undiminishing
At peak of action potential voltage approaches Na+ equilibrium potential
Depolarization to the threshold potential activates voltage-gated Na+ channels. A positive feedback loop causes Na+ channels to further open.
Rapid depolarization occurs due to Na+ moving down its concentration and electrochemical gradient. Na+ channels rapidly inactivate.
Resting membrane potential; cell is permeable to K+
At peak of action potential voltage approaches Na+ equilibrium potential
Depolarization to the threshold potential activates voltage-gated Na+ channels. A positive feedback loop causes Na+ channels to further open.
Rapid depolarization occurs due to Na+ moving down its concentration and electrochemical gradient. Na+ channels rapidly inactivate.
Resting membrane potential; cell is permeable to K+
At peak of action potential voltage approaches Na+ equilibrium potential
Depolarization to the threshold potential activates voltage-gated Na+ channels. A positive feedback loop causes Na+ channels to further open.
Rapid depolarization occurs due to Na+ moving down its concentration and electrochemical gradient. Na+ channels rapidly inactivate.
Resting membrane potential; cell is permeable to K+
At peak of action potential voltage approaches Na+ equilibrium potential
Depolarization to the threshold potential activates voltage-gated Na+ channels. A positive feedback loop causes Na+ channels to further open.
Rapid depolarization occurs due to Na+ moving down its concentration and electrochemical gradient. Na+ channels rapidly inactivate.
Resting membrane potential; cell is permeable to K+
Voltage gated K+ channels inactivate
The NaK-ATP-ase gradually restores the ionic gradients
Voltage gated K+ channels open causing repolarization
Resting membrane potential is restored
Voltage gated K+ channels inactivate
The NaK-ATP-ase gradually restores the ionic gradients
Voltage gated K+ channels open causing repolarization
Resting membrane potential is restored
Voltage gated K+ channels inactivate
The NaK-ATP-ase gradually restores the ionic gradients
Voltage gated K+ channels open causing repolarization
Resting membrane potential is restored
Voltage gated K+ channels inactivate
The NaK-ATP-ase gradually restores the ionic gradients
Voltage gated K+ channels open causing repolarization
Resting membrane potential is restored
Its activation and inactivation gates are open
Its activation and inactivation gates are closed
Its activation gate is open and its inactivation gate is closed
Its activation gate is closed and its inactivation gate is open
Its activation and inactivation gates are open
Its activation and inactivation gates are closed
Its activation gate is open and its inactivation gate is closed
Its activation gate is closed and its inactivation gate is open
Its activation and inactivation gates are open
Its activation and inactivation gates are closed
Its activation gate is open and its inactivation gate is closed
Its activation gate is closed and its inactivation gate is open
The neuron cannot be restimulated
Na+ channels are inactivated
Greater stimulation required to trigger acion potential
K+ channels are still activated
The neuron cannot be restimulated
Na+ channels are inactivated
Greater stimulation required to trigger acion potential
K+ channels are still activated
Neuron class
Axon diameter
Myelination
Concentration of Na+ within the cell