DPT 712: NERVE, NERVE CONDUCTANCE, ACTION POTENTIALS
AND NEURONAL SIGNALING EXAM QUESTIONS AND
ANSWERS VERIFIED GRADED A++
dendrite
where information comes to
presynaptic
nerve cell that releases a neurotransmitter into a synapse; before the synapse
post-synaptic
the nerve cell to which the neurotransmitter binds.
cell membranes create a separation of electrical charges and ion concentrations
creating an __________________ gradient and a __________________ potential
electrochemical; membrane
what ion plays the most important role in generating the resting membrane
potential
K+ (potassium)
Resting Membrane Potential
-separated electrical charges of opposite signs create a potential difference (like a
battery) called.....
-the size of this potential difference is determined by the difference in amount of charge
between the 2 compartments which reflect ionic concentrations
, what happens to resting membrane potential of cardiac muscle cells when the
outside concentration of K+ declines by 50%?
makes it more negative and then makes it harder for the axon to conduct action
potential
Membrane Potentials
this depends on 2 factors:
-difference in specific ion concentrations in the intracellular and extracellular fluids
-differences in membrane permiability to the different ions which then reflect the number
of open/closed channels for the different ions in the plasma membrane
How does the membrane potential move?
1. no ion movement, all ion channels closed
2. K+ channels open, K+ moves down its concentration gradient. Na+ ions do not move
as their channels are closed
3. After a few K+ ions have moved, the "compartments will have an excess of positive
charges, leaving behind an excess of negative charge.
4. Electrical gradient differences (increased negativity) will attract K+ ions back into the
compartment
5. An equilibrium for K+ will be established by a concentration gradient favoring the
movement of K+ into the compartment 2 and the increased negativity in compartment 1
electrical gradient, pulling K+ back into compartment 1
6. system will achieve equilibrium when these two opposing movements reach a value
of 0.
AND NEURONAL SIGNALING EXAM QUESTIONS AND
ANSWERS VERIFIED GRADED A++
dendrite
where information comes to
presynaptic
nerve cell that releases a neurotransmitter into a synapse; before the synapse
post-synaptic
the nerve cell to which the neurotransmitter binds.
cell membranes create a separation of electrical charges and ion concentrations
creating an __________________ gradient and a __________________ potential
electrochemical; membrane
what ion plays the most important role in generating the resting membrane
potential
K+ (potassium)
Resting Membrane Potential
-separated electrical charges of opposite signs create a potential difference (like a
battery) called.....
-the size of this potential difference is determined by the difference in amount of charge
between the 2 compartments which reflect ionic concentrations
, what happens to resting membrane potential of cardiac muscle cells when the
outside concentration of K+ declines by 50%?
makes it more negative and then makes it harder for the axon to conduct action
potential
Membrane Potentials
this depends on 2 factors:
-difference in specific ion concentrations in the intracellular and extracellular fluids
-differences in membrane permiability to the different ions which then reflect the number
of open/closed channels for the different ions in the plasma membrane
How does the membrane potential move?
1. no ion movement, all ion channels closed
2. K+ channels open, K+ moves down its concentration gradient. Na+ ions do not move
as their channels are closed
3. After a few K+ ions have moved, the "compartments will have an excess of positive
charges, leaving behind an excess of negative charge.
4. Electrical gradient differences (increased negativity) will attract K+ ions back into the
compartment
5. An equilibrium for K+ will be established by a concentration gradient favoring the
movement of K+ into the compartment 2 and the increased negativity in compartment 1
electrical gradient, pulling K+ back into compartment 1
6. system will achieve equilibrium when these two opposing movements reach a value
of 0.
