Exam 2 PSB-3002 Review UPDATED ACTUAL Questions And Correct Answers
C
Terms in this set (72)
What is membrane potential? The electrical charge difference (voltage) across the cell membrane, resulting
from the difference in ion distribution between the inside and outside of the cell.
What is resting potential? The membrane potential of a neuron when it is not being altered by excitatory or
inhibitory postsynaptic potentials; typically about -70 mV.
What is action potential? The brief electrical impulse that provides the basis for conduction of information
along an axon, involving rapid depolarization followed by repolarization.
What two forces determine the distribution of ions across Diffusion (Concentration Gradient) and Electrostatic Pressure (Electrical Gradient).
the cell membrane?
What is the concentration gradient for potassium ions? Higher concentration inside the cell.
What is the concentration gradient for chloride ions? Higher concentration outside the cell.
What is the concentration gradient for sodium ions? Higher concentration outside the cell.
How are ion gradients maintained at rest? By the sodium-potassium pump and the semi-permeable nature of the membrane.
What is the function of the sodium-potassium pump? It pumps 3 sodium ions (Na+) out of the cell for every 2 potassium ions (K+)
pumped in, preserving the resting potential.
What triggers an action potential? The membrane potential must reach the threshold of excitation (approx. -55mV to
-65mV).
What happens during depolarization in an action Voltage-gated Na+ channels open, and Na+ rushes in.
potential?
, What happens during repolarization in an action Na+ channels close; voltage-gated K+ channels open, and K+ rushes out.
potential?
What occurs during hyperpolarization? K+ channels close slowly, allowing excess K+ to leak out, making the potential
more negative than resting.
How do ions pass through the cell membrane? Through voltage-gated ion channels.
What is the all-or-none law? Once an action potential is triggered, it propagates without decrement; its size is
independent of stimulus intensity.
How does myelin affect conduction velocity? Myelin insulates the axon, preventing charge leakage and allowing action
potentials to 'jump' between Nodes of Ranvier.
What is saltatory conduction? The conduction where the action potential 'jumps' from one Node of Ranvier to
the next in a myelinated axon.
What happens at the axon terminal when an action Depolarization causes voltage-gated calcium (Ca2+) channels to open.
potential arrives?
What occurs after calcium enters the axon terminal? Calcium binds to docking proteins, causing synaptic vesicles to fuse with the
presynaptic membrane and release neurotransmitters.
What are ionotropic receptors? Ligand-gated ion channels that open directly upon neurotransmitter binding,
causing fast and short-lived effects.
What are metabotropic receptors? G-protein coupled receptors that activate a second messenger upon
neurotransmitter binding, causing slower and longer-lasting effects.
What is EPSP? A partial depolarization of the postsynaptic membrane that makes the neuron
more likely to fire.
What is IPSP? A partial hyperpolarization of the postsynaptic membrane that makes the neuron
less likely to fire.
What is depolarization? A reduction in the membrane potential, making the inside more positive/less
negative.
What is hyperpolarization? An increase in the membrane potential, making the inside more negative.
What are the stages of the life cycle of a 1. Synthesis, 2. Storage, 3. Release, 4. Binding, 5. Deactivation.
neurotransmitter?
What is reuptake? The process where transporter molecules pump the neurotransmitter back into
the presynaptic terminal.
What is enzymatic degradation? The breakdown of neurotransmitters by enzymes in the synaptic cleft into inactive
metabolites.
C
Terms in this set (72)
What is membrane potential? The electrical charge difference (voltage) across the cell membrane, resulting
from the difference in ion distribution between the inside and outside of the cell.
What is resting potential? The membrane potential of a neuron when it is not being altered by excitatory or
inhibitory postsynaptic potentials; typically about -70 mV.
What is action potential? The brief electrical impulse that provides the basis for conduction of information
along an axon, involving rapid depolarization followed by repolarization.
What two forces determine the distribution of ions across Diffusion (Concentration Gradient) and Electrostatic Pressure (Electrical Gradient).
the cell membrane?
What is the concentration gradient for potassium ions? Higher concentration inside the cell.
What is the concentration gradient for chloride ions? Higher concentration outside the cell.
What is the concentration gradient for sodium ions? Higher concentration outside the cell.
How are ion gradients maintained at rest? By the sodium-potassium pump and the semi-permeable nature of the membrane.
What is the function of the sodium-potassium pump? It pumps 3 sodium ions (Na+) out of the cell for every 2 potassium ions (K+)
pumped in, preserving the resting potential.
What triggers an action potential? The membrane potential must reach the threshold of excitation (approx. -55mV to
-65mV).
What happens during depolarization in an action Voltage-gated Na+ channels open, and Na+ rushes in.
potential?
, What happens during repolarization in an action Na+ channels close; voltage-gated K+ channels open, and K+ rushes out.
potential?
What occurs during hyperpolarization? K+ channels close slowly, allowing excess K+ to leak out, making the potential
more negative than resting.
How do ions pass through the cell membrane? Through voltage-gated ion channels.
What is the all-or-none law? Once an action potential is triggered, it propagates without decrement; its size is
independent of stimulus intensity.
How does myelin affect conduction velocity? Myelin insulates the axon, preventing charge leakage and allowing action
potentials to 'jump' between Nodes of Ranvier.
What is saltatory conduction? The conduction where the action potential 'jumps' from one Node of Ranvier to
the next in a myelinated axon.
What happens at the axon terminal when an action Depolarization causes voltage-gated calcium (Ca2+) channels to open.
potential arrives?
What occurs after calcium enters the axon terminal? Calcium binds to docking proteins, causing synaptic vesicles to fuse with the
presynaptic membrane and release neurotransmitters.
What are ionotropic receptors? Ligand-gated ion channels that open directly upon neurotransmitter binding,
causing fast and short-lived effects.
What are metabotropic receptors? G-protein coupled receptors that activate a second messenger upon
neurotransmitter binding, causing slower and longer-lasting effects.
What is EPSP? A partial depolarization of the postsynaptic membrane that makes the neuron
more likely to fire.
What is IPSP? A partial hyperpolarization of the postsynaptic membrane that makes the neuron
less likely to fire.
What is depolarization? A reduction in the membrane potential, making the inside more positive/less
negative.
What is hyperpolarization? An increase in the membrane potential, making the inside more negative.
What are the stages of the life cycle of a 1. Synthesis, 2. Storage, 3. Release, 4. Binding, 5. Deactivation.
neurotransmitter?
What is reuptake? The process where transporter molecules pump the neurotransmitter back into
the presynaptic terminal.
What is enzymatic degradation? The breakdown of neurotransmitters by enzymes in the synaptic cleft into inactive
metabolites.
