Nervous System Physiology FINAL EXAM GUIDE
2025
|MOST COMMON QUESTIONS WITH CORRECTLY
VERIFIED ANSWERS|ALREADY A+
GRADED|GUARANTEED PASS
Depolarization - Any increase in Membrane Potential (becomes more positive/less
negative)
Hyperpolarization - Any decrease in Membrane Potential (becomes more negative /less
positive)
High Concentration of K+ (potassium ions) - Inside of the Neuron
High Concentration of Na+ (sodium ions) - Outside of the Neuron
Repolarization - Hyperpolarization which occurs when the K+ channels open and the
membrane potential drops from being (+) back to (-)
Occurs at +30 mV - Voltage Gated Potassium (K+) Channels Open
Occurs at -55 mV - Voltage Gated Sodium (Na+) Channels Open
Occurs at -70 mV - Resting Membrane Potential; Maintained by Na+ / K+ (Sodium /
Potassium) pumps
Undershoot - The hyperpolarization of neuron below resting potential following the
opening of the K+ channels
Membrane Potential - The difference in electrical charge between the inside and outside
of a cell
Action Potential - An electrical impulse which is transmitted down the length of an axon
Threshold - The membrane potential at which an action potential is generated
,Graded Potential - A change in membrane potential which does not generate an action
potential. Can be Excitatory or Inhibitory
Stimulus from the dendrites which increases membrane potential - Excitatory Graded
Potential
Stimulus from the dendrites which decreases membrane potential - Inhibitory Graded
Potential
Dendrites - Processes off of a neuron which receives incoming stimuli
Axon - Process of of a neuron down which an action potential is propagated
Absolute Refractory Period - Time during which a new action potential is impossible.
Lasts 1 millisecond. (-55mV -> -55mV)
Relative Refractory Period - Period of time in which a new action potential is inhibited but
not impossible. Requires a large stimulus to generate a new action potential due to the neuron
not being back at resting levels
Sodium Potassium Pump - A membrane protein which uses ATP to drive Sodium and
Potassium against their concentration gradients (3 sodium out / 2 potassium in the cell per ATP)
Molecules which can diffuse through the phospholipid bylayer - Small and Not Charged
(Non-polar)
Molecules which cannot diffuse through the phospholipid bylayer - Large, Charged, or
Polar
The Phospholipid Heads are - Hydrophilic
The Phospholipid Fatty Acid Tails are - Hydrophobic
Concentration Gradient - A difference in the concentration of a substance from one
location to another. Provides a driving force for the diffusion of the substance
Diffusion - The movement of a substance from a higher concentration towards a lower
concentration
Active Transport - The movement of a substance from a lower concentration towards a
higher concentration. Requires ATP powered protein pumps
Axon Hillock - Tapered edge of the cell body where incoming graded potentials are
consolidated
,Myelin Sheath - A layer of fatty tissue encasing some nerve fibers; enables faster
transmission of neural impulses
Nodes of Ranvier - Spaces between the cells which provide the Myelin Sheath. Contains a
high concentration of voltage gated ion channels (sodium and potassium)
Forms the Myelin Sheath in the CNS - Oligodendrocytes
Forms the Myelin Sheath in the PNS - Schwann Cells
Astrocytes - Forms the Blood Brain Barrier in the CNS
Microglia - Glial Cells which act as the immune system of the CNS
Ependymal Cells - Produces Cerebrospinal Fluid
Satelite Cells - Supports neurons in the PNS and helps regulate their micro-environments
Central Nervous System - Made up of structures within the Brain and Spinal Cord
Peripheral Nervous System - The sensory and motor neurons within the body. Outside of
the Brain and Spinal Cord
Somatic Nervous System - Division of the PNS which controls the skeletal muscle system
(under conscious control)
Autonomic Nervous System - Division of the PNS which controls structures outside of
conscious control (smooth muscle, cardiac muscle, etc)
Sympathetic Nervous System - Efferent pathway within the Autonomic Nervous System
which controls the fight or flight response (ex: Release of Adrenaline)
Parasympathetic Nervous System - Efferent pathway within the Autonomic Nervous
System which controls the "rest and repair" responses (ex: Lowering Heart Rate following
stressor)
Afferent Pathway - Pathway sending sensory information towards the CNS (PNS --> CNS)
Efferent Pathway - Pathway sending motor responses away from the CNS (CNS --> PNS)
Reflex Arc - The full pathway from stimulus in the PNS --> Integration in the CNS -->
Motor Response back in the PNS
Interneuron - Neuron contained within the CNS. Serves as the bridge between the
Afferent and Efferent Pathways
, Synapse - Site of communication between two neurons. (Synaptic Knob --> Dendrite/Cell
Body)
The physical space between the axon terminal of one neuron and the dendrite or cell body of
another neuron - Synaptic Cleft
Slower synapses which are more easily controlled - Chemical Synapse
Faster synapses which are not easily controlled - Electrical Synapse
Presynaptic Neuron - The neuron which sends a signal towards the synaptic cleft.
Releases Neurotransmitter
Postsynaptic Neuron - The neuron which receives neurotransmitter from the Synaptic
Cleft and generates a new graded potential towards the axon hillock.
Neurotransmitter - Chemical messengers which are released into the synaptic cleft and
bind to receptors on Postsynaptic neurons. Can be excitatory or inhibitory
Ligand Gated Ion Channels - Ion channels (membrane proteins) which open and close in
response to binding by a Ligand (Neurotransmitter)
Voltage Gated Ion Channels - Ion channels (membrane proteins) which open and close in
response to changes in Membrane Potential
The structure within the Axon Terminus which contains the Neurotransmitter before it is
released - Vesicle
The binding of a calcium ion to a vesicle in the axon terminus... - triggers the release of
the Neurotrasmitter into the Synaptic Cleft
NMDA Receptor/Protein - Ligand & Voltage Gated Glutamate Receptor which when
activated allows Ca2+ to enter the postsynaptic neuron. Contains a magnesium ion which blocks
the protein channel
Long Term Potentiation - The process by which a frequently stimulated synapse becomes
stronger over time
Long Term Depression - The process by which an infrequently stimulated synapse
becomes weaker over time
Results in a temporary increase in the sensitivity of a synapse - Early Phase Long Term
Potentiation
2025
|MOST COMMON QUESTIONS WITH CORRECTLY
VERIFIED ANSWERS|ALREADY A+
GRADED|GUARANTEED PASS
Depolarization - Any increase in Membrane Potential (becomes more positive/less
negative)
Hyperpolarization - Any decrease in Membrane Potential (becomes more negative /less
positive)
High Concentration of K+ (potassium ions) - Inside of the Neuron
High Concentration of Na+ (sodium ions) - Outside of the Neuron
Repolarization - Hyperpolarization which occurs when the K+ channels open and the
membrane potential drops from being (+) back to (-)
Occurs at +30 mV - Voltage Gated Potassium (K+) Channels Open
Occurs at -55 mV - Voltage Gated Sodium (Na+) Channels Open
Occurs at -70 mV - Resting Membrane Potential; Maintained by Na+ / K+ (Sodium /
Potassium) pumps
Undershoot - The hyperpolarization of neuron below resting potential following the
opening of the K+ channels
Membrane Potential - The difference in electrical charge between the inside and outside
of a cell
Action Potential - An electrical impulse which is transmitted down the length of an axon
Threshold - The membrane potential at which an action potential is generated
,Graded Potential - A change in membrane potential which does not generate an action
potential. Can be Excitatory or Inhibitory
Stimulus from the dendrites which increases membrane potential - Excitatory Graded
Potential
Stimulus from the dendrites which decreases membrane potential - Inhibitory Graded
Potential
Dendrites - Processes off of a neuron which receives incoming stimuli
Axon - Process of of a neuron down which an action potential is propagated
Absolute Refractory Period - Time during which a new action potential is impossible.
Lasts 1 millisecond. (-55mV -> -55mV)
Relative Refractory Period - Period of time in which a new action potential is inhibited but
not impossible. Requires a large stimulus to generate a new action potential due to the neuron
not being back at resting levels
Sodium Potassium Pump - A membrane protein which uses ATP to drive Sodium and
Potassium against their concentration gradients (3 sodium out / 2 potassium in the cell per ATP)
Molecules which can diffuse through the phospholipid bylayer - Small and Not Charged
(Non-polar)
Molecules which cannot diffuse through the phospholipid bylayer - Large, Charged, or
Polar
The Phospholipid Heads are - Hydrophilic
The Phospholipid Fatty Acid Tails are - Hydrophobic
Concentration Gradient - A difference in the concentration of a substance from one
location to another. Provides a driving force for the diffusion of the substance
Diffusion - The movement of a substance from a higher concentration towards a lower
concentration
Active Transport - The movement of a substance from a lower concentration towards a
higher concentration. Requires ATP powered protein pumps
Axon Hillock - Tapered edge of the cell body where incoming graded potentials are
consolidated
,Myelin Sheath - A layer of fatty tissue encasing some nerve fibers; enables faster
transmission of neural impulses
Nodes of Ranvier - Spaces between the cells which provide the Myelin Sheath. Contains a
high concentration of voltage gated ion channels (sodium and potassium)
Forms the Myelin Sheath in the CNS - Oligodendrocytes
Forms the Myelin Sheath in the PNS - Schwann Cells
Astrocytes - Forms the Blood Brain Barrier in the CNS
Microglia - Glial Cells which act as the immune system of the CNS
Ependymal Cells - Produces Cerebrospinal Fluid
Satelite Cells - Supports neurons in the PNS and helps regulate their micro-environments
Central Nervous System - Made up of structures within the Brain and Spinal Cord
Peripheral Nervous System - The sensory and motor neurons within the body. Outside of
the Brain and Spinal Cord
Somatic Nervous System - Division of the PNS which controls the skeletal muscle system
(under conscious control)
Autonomic Nervous System - Division of the PNS which controls structures outside of
conscious control (smooth muscle, cardiac muscle, etc)
Sympathetic Nervous System - Efferent pathway within the Autonomic Nervous System
which controls the fight or flight response (ex: Release of Adrenaline)
Parasympathetic Nervous System - Efferent pathway within the Autonomic Nervous
System which controls the "rest and repair" responses (ex: Lowering Heart Rate following
stressor)
Afferent Pathway - Pathway sending sensory information towards the CNS (PNS --> CNS)
Efferent Pathway - Pathway sending motor responses away from the CNS (CNS --> PNS)
Reflex Arc - The full pathway from stimulus in the PNS --> Integration in the CNS -->
Motor Response back in the PNS
Interneuron - Neuron contained within the CNS. Serves as the bridge between the
Afferent and Efferent Pathways
, Synapse - Site of communication between two neurons. (Synaptic Knob --> Dendrite/Cell
Body)
The physical space between the axon terminal of one neuron and the dendrite or cell body of
another neuron - Synaptic Cleft
Slower synapses which are more easily controlled - Chemical Synapse
Faster synapses which are not easily controlled - Electrical Synapse
Presynaptic Neuron - The neuron which sends a signal towards the synaptic cleft.
Releases Neurotransmitter
Postsynaptic Neuron - The neuron which receives neurotransmitter from the Synaptic
Cleft and generates a new graded potential towards the axon hillock.
Neurotransmitter - Chemical messengers which are released into the synaptic cleft and
bind to receptors on Postsynaptic neurons. Can be excitatory or inhibitory
Ligand Gated Ion Channels - Ion channels (membrane proteins) which open and close in
response to binding by a Ligand (Neurotransmitter)
Voltage Gated Ion Channels - Ion channels (membrane proteins) which open and close in
response to changes in Membrane Potential
The structure within the Axon Terminus which contains the Neurotransmitter before it is
released - Vesicle
The binding of a calcium ion to a vesicle in the axon terminus... - triggers the release of
the Neurotrasmitter into the Synaptic Cleft
NMDA Receptor/Protein - Ligand & Voltage Gated Glutamate Receptor which when
activated allows Ca2+ to enter the postsynaptic neuron. Contains a magnesium ion which blocks
the protein channel
Long Term Potentiation - The process by which a frequently stimulated synapse becomes
stronger over time
Long Term Depression - The process by which an infrequently stimulated synapse
becomes weaker over time
Results in a temporary increase in the sensitivity of a synapse - Early Phase Long Term
Potentiation
