Neurophysiology Week 2 Flashcards
Presynaptic neuron =
sending neuron
Post synaptic=
recieving neuron
EPSP stands for
Excited post synaptic potential
IPSP stands for
Inhibitory post synaptic potential
Neuron cell membrane is______
polarixed
resting potential =
-70
Only allows certain things through
Bilipid membrance
Only allows ions down concentration gradient
Highly permeable
There is more ____ inside the cell:
potassium
There is more _____ outside the cell
Sodium, chloride ions
__ potassium in: __ sodium out
2:3
Passive ion distribution includes:
concentration gradients and electrostatic pressue
Action ion distribution includes:
pumps
Resistant to the passage of protein ions (-)
neuron at rest
resistant to the passage of Na+ ions
neuron at rest
Able to allow K+ and Cl- ions to pass fairly easily
neuron at rest
3 different ways there is a change in permeability
- chemically induced
- voltage induced
- Mechanical (alter shape)
Most common voltage to describe neurons:
-70 to -60
Depolarization of the membrane (goes toward zero)
EPSP
Hyperpolarization of the membrane (becomes more neg)
IPSP
when the cell is hyperpolarized before it resets, cell cant fire immediately and cell wont get damaged from firing to quickly and action potential cant fire backward
refractery period
Na+ channels open, Na+ begins to enter cell
Step 1: Action potential
K+ channels open, K+ begins to leave the cell (becoming to positive)
Step 2: Action potential
Na+ channels become refractory, no more Na+ enters cell (K+ stay open)
Step 3: Action potential
K+ continues to leave cell, causes membrane potential to return to resting level
Step 4: Action potential
K+ channels close, Na+ channels reset
Step 5: Action potential
Extra K+ outside diffuses away
Step 6: Action potential
The higher amoutn of EPSP will create ___ firing not ___ firing
more not greater
Voltage will decay is there is not whta?
additional channels or myelin
in bare plasma membrance, voltage ______
decays
In nonmyelinated axons, conduction is ____
slow
In myelinated axons, conductions is ____
fast (saltatory conduction)
the thicker/larger and more myelinated =
faster conduction
C fiber =
dull pain; slow
Delta fiber =
thicker/larger; pain
A fiber =
larger in diameter, allowing more change in cell and they are myelinated
