1. Neurophysio Part 1 : electrical props and AP Flashcards
done
_____ are made in the cell and located intracellularly. They produce a more neg charge in the cell
protein
There is ______ NRG created from the chem conc gradient
potential nrg
________: the membrane potential when there is a balance btw electrical and chem forces
equilibrium potential
What are two effects that equilibrium potential is dependent on
- intra/extrcellular ionic concentration
2. electrical charge of ion
equilibrium potential predicts (2)
- direction of ionic flow
2. DRIVING FORCE
the loss of K+ results in a ____ charge on the inner plasma membrane face
negative charge
______: when there is only 1 ion affecting membrane potential
reversal potential
Equil potential for K+ is ______mV
-87mV
** most of the cells RMP is determined by the equil potential for ____
K+
Bc of the leaky K+ channels
RMP values for most cells range from ___ to ___mV
-65mV to -95mV
RMP is related to the conc. of what three ions
Na+, K+, and Cl-
According to GHK, RMP is related to what 2 factors?
conc gradient of ions (Na+, K+, Cl-)
cells permeability to each
at RMP the cell is ___x more permeable for K than other ions
1000s
What are the two major forces acting on the movement of ions across the cell membrane
- charge
- conc gradient
____ equation is used to determine the value of membrane potential when there is NO NET DIFFUSIOn of any 1 given ion
nernst equation
- will give the electrical potential NRG for 1 ion
____ equation is used to determine the RMP when there is NO NET DIFFUSION of ALL ions across the cell membrane
GHK
- gives the reversal potential
_____: the ionic flow that will occur once the channel opens
driving force
_____= RMP-equil. Potential
driving force
the larger the _____ , the faster the ionic current will travel
driving force
What are three channel types
leaky ions
ligand
voltage
** The _____ gated channel signal the ____ gated channel
ligand signal the voltage gated
Changes in membrane potential affect the props of _____
voltage gated
when the membrane potential moves ____mV toward positive the voltage gated channel will open
20mV
____ gated channels have an all or non mechanism
voltage gated
_______: the current flow of voltage gated channels depolarize and further AP regeneration along the neuronal axon , repeats until it reaches the terminal
positive feedback loop
Na+ channels use 2 mech to allow ionic flow across the membrane
- ligand gated channels (AcH)
2. voltage gated channels
What is the neurotransmitter that is used to stim the ligand gated channel of Na+
AcH
EPSP is due to ___ ions
Na+
IPSP is due to ___ ions
Cl-
______ ions cause hyperpolarization.
______ions cause depolarization
Cl- = hyperpolar Na+ = depolar
How is a graded potential turned into an AP
summation
- leakage in the membrane prevents EPSP from going straight into an AP
The EPSP has to be summed to threshold at ___ to ___ mV above resting potential for a spike to occur= AP
15 to 20mV
_____ : where the axon and the stoma meet. Has Na+ channels that can illiciate AP
axon hillock
Voltage gated Na+ channels inactivated via _____ mechanism
ball and chain
- keeps the AP moving in one direction
___ voltage gated channels only open after the cell has depolarized so much that the membrane is close to +30mV
K+
(overshoots)
- at this pt there is a driving force for K+ to move out so that it can go back to its equil of -90mV (repolarize)
K+ equilibrium potential is ____ mV. When this membrane potential is reached the cell is said to be in ____
-90mV = Repolarization
Na+/K+ ATPase pump begins working when it senses an increase in intracellular ____ conc
Na+
____period: voltage gated Na+ channels woll not open, regardless of stim strength
absolute refractory period
_____period: the voltage gated K+ channels have opened, the driving force for K+ to leave the cell is stronger than the driving force for Na+ to enter
relative refractory period
- must have a very high Na+ stim for an AP to be acheiveable
____: the degree to which ion channels are open for a given area on the cell membrane
conductance
Conductance is the inverse of _____
resistance
Ohm law equation
V= I x R
velocity = current X resistance
greater resistance in the membrane than in the cytoplasm, the current will tens to flow through the ____rather than leak back out into the ___
flow through the cytoplasm
instead of back out into membrane
(path of least resistance)
the fatter the axon, the ______ it has for ions to flow in
more area
______ causes axons to conduct AP faster
myeline
______: myelinates axons conduct AP faster than unmyelinates axons
saltatory conduction
____ channels are used in vesicle binding and release of neurotransmitter
voltage gated Ca+2
voltage gates Ca+2 channels are used in ___ binding and release of ____
vesicle binding and release of NT
____ & ___ are docking proteins that tie vesicles to active zones
actin & synaptophysin
Ca+2 causes ____ to contract, and bring vesicles forward to the membrane
actin
2 actions that occur when there is a Ca+2 influx
- causes actin to contract - brings vesicles forward
2. activates Calmodulin, causes release of vesicle content into the cleft
When Ca+2 binds to ____ , vesicle content is released into the cleft
calmodulin
____ helps to withdraw vesicle components back into the synaptic cleft after Ca_2 binds to calmodulin
clathrin
A ___ amt of NT is released for ea. AP
fixed
