PSIO 201 Exam 5 Question and
answers rated A+ 2025/2026
nerve cells - correct answer ✔involved in the generation and interpretation of electrical signals
neuroglia - correct answer ✔support neuronal cell activity
dendrites - correct answer ✔collect info
cell body - correct answer ✔process info
axon - correct answer ✔propagate info to synapses
synapses - correct answer ✔transmit info
bioelectricity - correct answer ✔-resting membrane potential
-action potential
~ALL CELLS negative on the inside compared to the outside
resting membrane potential - correct answer ✔-baseline electrical condition of all cells
-depends on two parameters
two parameters of resting membrane potential - correct answer ✔1. transmembrane ion gradients (Na
and K)
2. membrane permeability to those ions
,what's very high extracellularly? - correct answer ✔Na and Cl
Whats very high intracellularly? - correct answer ✔K
Na,K-ATPase - correct answer ✔develops and maintains steady state ion gradients for all cells
2 K in, 3 Na out
-PRIMARY TRANSPORT, requires ATP
Resting membrane potential depends on... - correct answer ✔1. ion gradients
2. permeability
ion gradients - correct answer ✔Na, K ATP ase
-2 K in, 3 Na out
permeability - correct answer ✔1. pumping creates ionic gradient for K+
2. K+ "leaks" out, down its concentration gradient, so that the inside of the cell becomes more negative
3. now two kinds of forces push/pull on K+: chemical and electrical
-maintain stable membrane resting potential
2 opposing forces of membrane potential... - correct answer ✔chemical and electrical
chemical force - correct answer ✔- K+ gradient
-tends to push K+ out
, electrical force - correct answer ✔developed electrical force
-inside becomes negative
-negative charges
what doesn't leak very well? - correct answer ✔Na+ does not leak into the cell very well (not
permeable to it)
in a typical cell... - correct answer ✔chemical and electrical forces for K+ are nearly in balance
(electrically negative enough to oppose chemical gradient)
What does this mean for us?
1. outwardly directed K+ gradient results in an inside negative electrical potential
The electrical chemical difference (PVD) is measured in - correct answer ✔volts
-typical value -0.05 volts to -0.1 volts OR -30 to -100 millivolts
characteristic of all cells at rest - correct answer ✔***K+ dominated, inside negative membrane
potential
all cells resting membrane potential is set by... - correct answer ✔K+
at rest... - correct answer ✔-membrane is polarized
-equal #s of positive and negative charges in ECF, near plasma membrane, and cytosol (ICF)
modulation of the membrane potential - correct answer ✔-changes in membrane permeability can
produce large changes in the membrane potential
answers rated A+ 2025/2026
nerve cells - correct answer ✔involved in the generation and interpretation of electrical signals
neuroglia - correct answer ✔support neuronal cell activity
dendrites - correct answer ✔collect info
cell body - correct answer ✔process info
axon - correct answer ✔propagate info to synapses
synapses - correct answer ✔transmit info
bioelectricity - correct answer ✔-resting membrane potential
-action potential
~ALL CELLS negative on the inside compared to the outside
resting membrane potential - correct answer ✔-baseline electrical condition of all cells
-depends on two parameters
two parameters of resting membrane potential - correct answer ✔1. transmembrane ion gradients (Na
and K)
2. membrane permeability to those ions
,what's very high extracellularly? - correct answer ✔Na and Cl
Whats very high intracellularly? - correct answer ✔K
Na,K-ATPase - correct answer ✔develops and maintains steady state ion gradients for all cells
2 K in, 3 Na out
-PRIMARY TRANSPORT, requires ATP
Resting membrane potential depends on... - correct answer ✔1. ion gradients
2. permeability
ion gradients - correct answer ✔Na, K ATP ase
-2 K in, 3 Na out
permeability - correct answer ✔1. pumping creates ionic gradient for K+
2. K+ "leaks" out, down its concentration gradient, so that the inside of the cell becomes more negative
3. now two kinds of forces push/pull on K+: chemical and electrical
-maintain stable membrane resting potential
2 opposing forces of membrane potential... - correct answer ✔chemical and electrical
chemical force - correct answer ✔- K+ gradient
-tends to push K+ out
, electrical force - correct answer ✔developed electrical force
-inside becomes negative
-negative charges
what doesn't leak very well? - correct answer ✔Na+ does not leak into the cell very well (not
permeable to it)
in a typical cell... - correct answer ✔chemical and electrical forces for K+ are nearly in balance
(electrically negative enough to oppose chemical gradient)
What does this mean for us?
1. outwardly directed K+ gradient results in an inside negative electrical potential
The electrical chemical difference (PVD) is measured in - correct answer ✔volts
-typical value -0.05 volts to -0.1 volts OR -30 to -100 millivolts
characteristic of all cells at rest - correct answer ✔***K+ dominated, inside negative membrane
potential
all cells resting membrane potential is set by... - correct answer ✔K+
at rest... - correct answer ✔-membrane is polarized
-equal #s of positive and negative charges in ECF, near plasma membrane, and cytosol (ICF)
modulation of the membrane potential - correct answer ✔-changes in membrane permeability can
produce large changes in the membrane potential
