Chemistry and Physics in Nurse
Anesthesia - Test 3
What is membrane potential?
What is the value? - CORRECT ANSWER ✔✔✔ A voltage or electrical charge across the plasma
membrane
Average: -60- -90 mV
With membrane potential, what is the "inside" charge relative to the "outside?" - CORRECT ANSWER
✔✔✔ We consider the "inside" negative to the "outside"
The outside is the ECF
What is the charge that we consider the ECF to have? - CORRECT ANSWER ✔✔✔ Zero millivolts, or the
electrical "ground"
What is the diameter of squid giant axons? - CORRECT ANSWER ✔✔✔ 0.5-1mm
Which ions are responsible for membrane potential? - CORRECT ANSWER ✔✔✔ Na+, K+, Cl-, proteins
Through ions channels, potassium is able to travel at ____x the velocity of sodium*
This creates a _________ charge - CORRECT ANSWER ✔✔✔ 100
Negative charge
The resting membrane potential (voltage gradient) is determined by: - CORRECT ANSWER ✔✔✔ 80%
unequal ion transport
20% sodium potassium pump
What is the concentration of sodium ions outside and inside of the cell? - CORRECT ANSWER ✔✔✔
Extracellular: 145 mM/L
Intracellular: 10 mM/L
What is the concentration of potassium ions outside and inside of the cell? - CORRECT ANSWER ✔✔✔
Extracellular: 5 mM/L
,Intracellular: 140 mM/L
Na enters the cell through ________ channels - CORRECT ANSWER ✔✔✔ non-gated
K leave the cell through ___________ channels - CORRECT ANSWER ✔✔✔ non-gated
What is the ratio of membrane permeability (unequal ion transport) - CORRECT ANSWER ✔✔✔ Na 1 K
100
What is the relationship between permeability and velocity? - CORRECT ANSWER ✔✔✔ Almost equal
With the Sodium-Potassium Pump (electrogenic pump), what is the ion exchange? - CORRECT ANSWER
✔✔✔ 3Na pumped out for every 2K brought inside the cell
How may we relate electron forces to large distances? - CORRECT ANSWER ✔✔✔ Membrane potential
= 80 mV
Membrane = 10 nm
10x10(^-9) m or 80,000 V/cm
What are the two driving forces across the membrane? - CORRECT ANSWER ✔✔✔ Concentration
(chemical) gradient across the membrane
Electrical potential across the membrane
What is the formula for chemical energy? - CORRECT ANSWER ✔✔✔ E = RTln (c(out)/c(in))
What is the formula for electrical energy? - CORRECT ANSWER ✔✔✔ E = zF(Eo - Ei)
Eo =
How do we define the energy created by neutral particles? - CORRECT ANSWER ✔✔✔ Chemical Energy
How do we define the energy created by ions? - CORRECT ANSWER ✔✔✔ Electrical energy
What is the driving force for Fick's law? - CORRECT ANSWER ✔✔✔ Electrochemical potential (chemical
+ electrical energy)
What does the Nernst equation describe? - CORRECT ANSWER ✔✔✔ The relationship between the
concentrations of an ion on either side of the cell membrane and electrical potential (E) is known as
Nernst equation
Nernst equation relates the value of the electrical potential difference and the specific ion at
equilibrium, when the membrane is permeable only to that ion
, What is the Nernst equation? - CORRECT ANSWER ✔✔✔ E(in)-E(out) = (RT)/(zF) log10(c(out)/c(in))
What factors influence nerve excitement or depression? - CORRECT ANSWER ✔✔✔ Chemical
substances
Mechanical stimulation
Electrical stimulation
Temperautre
The registered action potential (compound action potential) is composed of - CORRECT ANSWER ✔✔✔
a combination of single action potentials
What is the action potential initiated? Why? - CORRECT ANSWER ✔✔✔ The trigger zone (axon hillock)
It has a high density of VOC sodium and potassium channels
What does depolarization represent in action potential? - CORRECT ANSWER ✔✔✔ An increase in
sodium permeability - opening of the VOC sodium channels
What does repolarization represent in action potential? - CORRECT ANSWER ✔✔✔ Increase in
potassium permeability - opening of VOC potassium channels
What is the absolute refractory period? - CORRECT ANSWER ✔✔✔ Time from the opening of the Na+
activation gates until the closing of inactivation gates.
Prevents the neuron from generating an action potential.
Ensures that each action potential is separate. Enforces one way transmission of nerve impulses.
What is the amount of time needed for depolarization? - CORRECT ANSWER ✔✔✔ 1 millisecond
What is the amount of time needed for repolarization and resting level to be achieved? - CORRECT
ANSWER ✔✔✔ 1 - 2 milliseconds
What are four traits that allow propagation of action potential and conduction velocities? - CORRECT
ANSWER ✔✔✔ 1. Conduction by local current
2. Saltatory conduction
3. Axon diameter
4. Myelin
Axons Classification and Conduction Velocities?
Anesthesia - Test 3
What is membrane potential?
What is the value? - CORRECT ANSWER ✔✔✔ A voltage or electrical charge across the plasma
membrane
Average: -60- -90 mV
With membrane potential, what is the "inside" charge relative to the "outside?" - CORRECT ANSWER
✔✔✔ We consider the "inside" negative to the "outside"
The outside is the ECF
What is the charge that we consider the ECF to have? - CORRECT ANSWER ✔✔✔ Zero millivolts, or the
electrical "ground"
What is the diameter of squid giant axons? - CORRECT ANSWER ✔✔✔ 0.5-1mm
Which ions are responsible for membrane potential? - CORRECT ANSWER ✔✔✔ Na+, K+, Cl-, proteins
Through ions channels, potassium is able to travel at ____x the velocity of sodium*
This creates a _________ charge - CORRECT ANSWER ✔✔✔ 100
Negative charge
The resting membrane potential (voltage gradient) is determined by: - CORRECT ANSWER ✔✔✔ 80%
unequal ion transport
20% sodium potassium pump
What is the concentration of sodium ions outside and inside of the cell? - CORRECT ANSWER ✔✔✔
Extracellular: 145 mM/L
Intracellular: 10 mM/L
What is the concentration of potassium ions outside and inside of the cell? - CORRECT ANSWER ✔✔✔
Extracellular: 5 mM/L
,Intracellular: 140 mM/L
Na enters the cell through ________ channels - CORRECT ANSWER ✔✔✔ non-gated
K leave the cell through ___________ channels - CORRECT ANSWER ✔✔✔ non-gated
What is the ratio of membrane permeability (unequal ion transport) - CORRECT ANSWER ✔✔✔ Na 1 K
100
What is the relationship between permeability and velocity? - CORRECT ANSWER ✔✔✔ Almost equal
With the Sodium-Potassium Pump (electrogenic pump), what is the ion exchange? - CORRECT ANSWER
✔✔✔ 3Na pumped out for every 2K brought inside the cell
How may we relate electron forces to large distances? - CORRECT ANSWER ✔✔✔ Membrane potential
= 80 mV
Membrane = 10 nm
10x10(^-9) m or 80,000 V/cm
What are the two driving forces across the membrane? - CORRECT ANSWER ✔✔✔ Concentration
(chemical) gradient across the membrane
Electrical potential across the membrane
What is the formula for chemical energy? - CORRECT ANSWER ✔✔✔ E = RTln (c(out)/c(in))
What is the formula for electrical energy? - CORRECT ANSWER ✔✔✔ E = zF(Eo - Ei)
Eo =
How do we define the energy created by neutral particles? - CORRECT ANSWER ✔✔✔ Chemical Energy
How do we define the energy created by ions? - CORRECT ANSWER ✔✔✔ Electrical energy
What is the driving force for Fick's law? - CORRECT ANSWER ✔✔✔ Electrochemical potential (chemical
+ electrical energy)
What does the Nernst equation describe? - CORRECT ANSWER ✔✔✔ The relationship between the
concentrations of an ion on either side of the cell membrane and electrical potential (E) is known as
Nernst equation
Nernst equation relates the value of the electrical potential difference and the specific ion at
equilibrium, when the membrane is permeable only to that ion
, What is the Nernst equation? - CORRECT ANSWER ✔✔✔ E(in)-E(out) = (RT)/(zF) log10(c(out)/c(in))
What factors influence nerve excitement or depression? - CORRECT ANSWER ✔✔✔ Chemical
substances
Mechanical stimulation
Electrical stimulation
Temperautre
The registered action potential (compound action potential) is composed of - CORRECT ANSWER ✔✔✔
a combination of single action potentials
What is the action potential initiated? Why? - CORRECT ANSWER ✔✔✔ The trigger zone (axon hillock)
It has a high density of VOC sodium and potassium channels
What does depolarization represent in action potential? - CORRECT ANSWER ✔✔✔ An increase in
sodium permeability - opening of the VOC sodium channels
What does repolarization represent in action potential? - CORRECT ANSWER ✔✔✔ Increase in
potassium permeability - opening of VOC potassium channels
What is the absolute refractory period? - CORRECT ANSWER ✔✔✔ Time from the opening of the Na+
activation gates until the closing of inactivation gates.
Prevents the neuron from generating an action potential.
Ensures that each action potential is separate. Enforces one way transmission of nerve impulses.
What is the amount of time needed for depolarization? - CORRECT ANSWER ✔✔✔ 1 millisecond
What is the amount of time needed for repolarization and resting level to be achieved? - CORRECT
ANSWER ✔✔✔ 1 - 2 milliseconds
What are four traits that allow propagation of action potential and conduction velocities? - CORRECT
ANSWER ✔✔✔ 1. Conduction by local current
2. Saltatory conduction
3. Axon diameter
4. Myelin
Axons Classification and Conduction Velocities?
