Neurophysiology

Question 1

What elements are in the ECF vs. ICF

Answer 1

ECF
- More Na and Cl
- Less K
ICF
- More K
- Less Na and Cl
- Anions (proteins)

Question 2

What is the mV for Resting Membrane Potential (vr)
- Polarized or nonpolarized?

Answer 2

-70mV
-Polarized

Question 3

AP vs. GP (Action)

Answer 3

-Voltage gates
-Na Channels
-K Channels
All or Nothing
- Change of -70mV > +30mV (Change of 100mV)
- Travel long distances
- Long life
-Self-propagating

Question 4

AP vs. GP (Graded)

Answer 4

Chemical gates
2 Types
1. Na/K move together
2. Cl/K move together
- Change is variable & Depends on the # of gates that open
- Can never be an AP
- Triggers AP by reaching Threshold
- Short Travelers
- Short-lived

Question 5

What are the 8 steps of the Action Potential

Answer 5

1. Resting Membrane Potential
2. Graded Potential
3. Threshold
4. Depolarization
5. At +30mV = Peak of the AP
6. Repolarization
7. Undershooting
8. Na/K Pump returns

Question 6

Processes for:
1. Resting Membrane Potential
2. Graded potential

Answer 6

1. Na channels - 2 gates
   a. Fast (activation) gate - closed
   b. Slow (Inactivation) gate - open
   - Low Na permeability
   - K gate closed
2. -Doesn’t always reach threshold
   
   • Triggers AP by reaching threshold

Question 7

Processes for:
3. Threshold
4. Depolarization

Answer 7

3. Threshold = -50mV (-55)
   - Fast Na gate opens
   - Influx of Na > Depolarization
   - K gates remain closed
4. Occurs until +30mV

Question 8

Processes for:
5. Peak of the AP
6. Repolarization

Answer 8

5. Peak of the AP is at +30mV
   - Slow Na gate closes
   - K channels open
6. Na gates return back to Resting State
   - Slow gate opens
   - Fast gate closes

Question 9

Processes for:
7. Undershooting
8. Na/K Pump returns

Answer 9

7. Hyperpolarization = -90mV
   - K Equilibrium Potential
   - Eventually, the K gates will close
8. Membrane to Vr = -70mV

Question 10

Refractory Periods:
1. Absolute RP
2. Relative RP

Answer 10

1. • One way
   • Na Channels open
2. • Na channels have reset during Repolarization
   • Increase Frequency

Question 11

What 4 ways stop the Neurotransmitter release/stimulus

Answer 11

1. Hydrolysis - AchE
2. Re-uptake
3. Diffusion
4. Astrocytes

Question 12

What are the 2 Post Synaptic Responses = Graded Potentials

Answer 12

1. Excitatory = Depolarization
2. Inhibitory = Hyperpolarization

Question 13

1. Excitatory Responses: Excitatory Post-synaptic potential process

Answer 13

-Depolarization
-Dendrites
-Chemical Regulated Channels
Na/K

Question 15

Mnemonic for CN III , IV, VI

Answer 15

SO4 - superior oblique
LR6 - Lateral Rectus
REST3 - the rest of the eye muscles

Question 16

Mnemonic for CN III , IV, VI

Answer 16

SO4
LR6
REST3