Neurobiology Exam 1 IAHSS
ADVANCED OFFICER CERTIFICATIONS
EXAMS |ACCURATE TESTING
VERSIONS
Membrane potential (Vm) - ANSWER-Electrical potential inside the cell,
compared to outside
Measured by sticking an electrode into a neuron
Measure in millvolts (mV)
Resting membrane potential (Vrest) - ANSWER-At rest, the membrane
is negative on the inside relative to the outside
In the absence of stimulation
Typically around -60 mV for neurons
Depolarization - ANSWER-Vm becomes more positive
Hyperpolarization - ANSWER-Vm becomes more negative
,Passive responses - ANSWER-Graded membrane potentials that decay
the further away you get
Active response - ANSWER-All or none action potential
You reach threshold
Simple diffusion - ANSWER-Movement of a solute from an area of high
concentration to an area of low concentration directly through the
plasma membrane
Facilitated diffusion - ANSWER-Movement of specific molecules across
cell membranes through protein channels down their concentration
gradient
Electrochemical gradient - ANSWER-The diffusion gradient of an ion,
representing a type of potential energy that accounts for both the
concentration difference of the ion across a membrane and its
tendency to move relative to the membrane potential
Equilibrium - ANSWER-Reached when electrical and chemical gradients
are equal and opposite for an ion
, Electrical potential (Eion) - ANSWER-One electrical voltage that creates
an electrical gradient equal and opposite to the concentration gradient
Described by the Nernst equation
No net movement of ions at this point
Goldman equation - ANSWER-A mathematical relationship used to
predict membrane potential from the concentrations and membrane
permeabilities of multiple ions
Vm depends on... - ANSWER-Both the equilibrium potential for each ion
AND relative permeability for each ion (which is related to the number
of channels open)
Permeability coefficient - ANSWER-An estimate of the ease by which a
molecule can pass through a cellular membrane
No units, just a relative number
High ___ = more ion movement
At rest - ANSWER-At this point, the permeability of potassium is much
larger than the permeability of sodium
Because there are more K+ channels open than Na+ channels
ADVANCED OFFICER CERTIFICATIONS
EXAMS |ACCURATE TESTING
VERSIONS
Membrane potential (Vm) - ANSWER-Electrical potential inside the cell,
compared to outside
Measured by sticking an electrode into a neuron
Measure in millvolts (mV)
Resting membrane potential (Vrest) - ANSWER-At rest, the membrane
is negative on the inside relative to the outside
In the absence of stimulation
Typically around -60 mV for neurons
Depolarization - ANSWER-Vm becomes more positive
Hyperpolarization - ANSWER-Vm becomes more negative
,Passive responses - ANSWER-Graded membrane potentials that decay
the further away you get
Active response - ANSWER-All or none action potential
You reach threshold
Simple diffusion - ANSWER-Movement of a solute from an area of high
concentration to an area of low concentration directly through the
plasma membrane
Facilitated diffusion - ANSWER-Movement of specific molecules across
cell membranes through protein channels down their concentration
gradient
Electrochemical gradient - ANSWER-The diffusion gradient of an ion,
representing a type of potential energy that accounts for both the
concentration difference of the ion across a membrane and its
tendency to move relative to the membrane potential
Equilibrium - ANSWER-Reached when electrical and chemical gradients
are equal and opposite for an ion
, Electrical potential (Eion) - ANSWER-One electrical voltage that creates
an electrical gradient equal and opposite to the concentration gradient
Described by the Nernst equation
No net movement of ions at this point
Goldman equation - ANSWER-A mathematical relationship used to
predict membrane potential from the concentrations and membrane
permeabilities of multiple ions
Vm depends on... - ANSWER-Both the equilibrium potential for each ion
AND relative permeability for each ion (which is related to the number
of channels open)
Permeability coefficient - ANSWER-An estimate of the ease by which a
molecule can pass through a cellular membrane
No units, just a relative number
High ___ = more ion movement
At rest - ANSWER-At this point, the permeability of potassium is much
larger than the permeability of sodium
Because there are more K+ channels open than Na+ channels
