PBSI 333 - Exam 1 (Principles of Neurotransmission,
Chemical Neurotransmission, Principles of
Pharmacology) Questions and Answers Latest 2025
Top Rated A+
What is Anterograde Transport?
Movement from the Soma to the Axon Terminal
What is Retrograde Transport?
Movement up the Axon toward the Soma
How fast is Retrograde Transport compare to Anterograde Transport?
Retrograde transport is 2x slower than anterograde
Why is Retrograde transport necessary?
Retrograde transport happens in order to keep the connection with the neuron alive.
What goes through fast transport?
Enzymes, Vesicles, and Neurotransmitters.
Anything Important for activity is through fast transport.
Think: If it is important, we must transport it fast!
What goes through Slow Transport? What direction does it go in?
Slow transport is best for proteins, and it travels in only one direction.
What are Microglia?
They are the immune system cells of the CNS, acting as macrophages cleaning up
debris and pathogens.
Think: MICRO-glia, MICRO-immune system
What are the Macroglia?
Astrocytes, Oligodendrocytes, and Schwann Cells
What are Oligodendrocytes and Schwann Cells?
The two types of glial cells that form myelin sheaths around axons.
What is Myelin?
A white, fatty substance found in the myelin sheath around some nerve fibers.
What does the Myelin Sheath do?
Insulated the axon of some neurons and helps speed neural impulses
What are Astrocytes?
They are the MOST NUMEROUS GLIAL CELL, they fill spaces between neurons for
support, and regulate the composition of the extracellular space. It is important to note
that Astrocytes form a connection between neurons and capillaries. Astrocytes are
ONLY found in the brain.
They do everything except conduct action potentials.
What do Glial Cells do? What is the one thing they do NOT do?
They Support and protect neurons. They do NOT conduct action potentials.
Which glial cell produces myelination in the PNS?
Schwann Cells (1 cell myelinates 1 axon segment)
Which glial cell produces myelination in the CNS?
Oligodendrocytes (1 cell myelinates many axons)
What is Electrostatic Pressure?
,Causes ions to flow towards oppositely charged areas.
Like charges repel, opposites attract - ions move to balance the charge
What is Diffusion?
The movement of particles from an area of high concentration to an area of low
concentration.
Think: DIFFusion = DIFFerence in concentration drives flow
What do diffusion and electrostatic pressure form together?
The electrochemical gradient. (Concentration and Charge forces acting at once)
We use what two main processes for ATP? What are the pros and cons for each?
Glycolysis and The Krebs Cycle
Glycolysis doesnt produce as much ATP, but it is the more efficient one. The Krebs
Cycle produces an abundant amount of ATP, however it is not as efficient and requires
a lot more.
What does electrostatic diffusion do to potassium ions (K+)?
Potassium (K+) is high inside: Diffusion pushes out, electrostatic pulls in (inside is -)
What does electrostatic diffusion do to sodium ions (Na+)?
Sodium (Na+) is high outside: both forces push it in
What does electrostatic diffusion do to chloride ions (Cl-)?
Chloride (Cl-) is high outside: Diffusion in, electrostatic (inside is -) pushes it out -> the
net depends on channels
What is Depolarization?
The inside of the membrane becomes less negative and more positive.
This term refers to when any time the charge difference becomes more positive than the
RPM of - 70mV. moving closer to zero.
What is hyperpolarization?
membrane potential becomes more negative
What does depolarization do?
Opens Na+ channels and makes it more likely to fire an action potential
What does Hyperpolarization do?
An increase in the membrane potential of a cell, relative to the normal resting potential.
Makes it less likely that a nerve impulse (action potential) will fire.
What are Cable Properties?
The passive conduction of electrical current, in a gradual decrease, down the length of
an axon.
What is the purpose for Cable Properties?
Dendrites dont have action potentials, the have cable properties.
How do Cable Properties compare to Action Potentials?
Cable properties are good for short distances, they are fast, and they dont require a lot
of energy. However, there is a limited distance to which they can travel (only short
distances), and only one intensity.
Action Potentials require more energy but they can travel further, and they have a
stronger intensity (all or none).
, What is an Action Potential?
An electrical impulse that travels down the axon triggering the release of
neurotransmitters
How is an Action Potential generated?
As an action potential travels down the axon, there is a change in polarity across the
membrane. The Na+ and K+ gated ion channels open and close as the membrane
reaches the threshold potential, in response to a signal from another neuron.
What is the threshold of excitation?
The value of the membrane potential that must be reached to produce an action
potential. (-55mV)
There is no ______ of action potentials, why is this?
Intensity. This is because of the all or none principle.
What is the All or None Law of an Action Potential?
The principle that once an action potential is triggered in an axon, it is propagated,
without slowing down, to the end of the fiber. It gives it ALL or NOTHING. There is no
level of intensity.
What is an Ion (Ligand-Gated) Channel?
It is a specialized protein molecule that permits specific ions to enter or leave the cells.
They open when a neurotransmitter binds.
What is a Voltage-dependent ion channel?
an ion channel that opens or closes according to the value of the membrane voltage
(Na+, K+, Ca2+)
What are two types of voltage-dependent channels?
Sodium and Potassium
The Sodium Channel is activated by ______ and stays open based on _____.
Voltage; Time
Once activated by voltage, the sodium channel has a limited time that is stays open.
This is like flipping a sand timer upside down.
The Potassium Channel is activated by ______ and stays open based on _____.
Voltage; Voltage
Once activated by voltage, the potassium channel will remain open as long as the
voltage is above the threshold for an action potential. If it is below, the channel will
close.
What is the purpose of the sodium-potassium transporter?
Neurons fire multiple action potentials at a time which means a lot of sodium will begin
to accumulate in the cell, which will depolarize it. The solution for this is the sodium-
potassium transporter because it allows 1 K+ in for every 3 Na+ out. It prevents the
build up of sodium in the cell.
When will sodium stop entering the cell?
When the equilibrium gets off balance (the cell gets too positive) or when the channel
closes (its on a timer)
What is the Sodium-Potassium Transporter?
A protein found in the membrane of all cells that extrudes sodium ions from and
transports potassium ions into the cell.
Chemical Neurotransmission, Principles of
Pharmacology) Questions and Answers Latest 2025
Top Rated A+
What is Anterograde Transport?
Movement from the Soma to the Axon Terminal
What is Retrograde Transport?
Movement up the Axon toward the Soma
How fast is Retrograde Transport compare to Anterograde Transport?
Retrograde transport is 2x slower than anterograde
Why is Retrograde transport necessary?
Retrograde transport happens in order to keep the connection with the neuron alive.
What goes through fast transport?
Enzymes, Vesicles, and Neurotransmitters.
Anything Important for activity is through fast transport.
Think: If it is important, we must transport it fast!
What goes through Slow Transport? What direction does it go in?
Slow transport is best for proteins, and it travels in only one direction.
What are Microglia?
They are the immune system cells of the CNS, acting as macrophages cleaning up
debris and pathogens.
Think: MICRO-glia, MICRO-immune system
What are the Macroglia?
Astrocytes, Oligodendrocytes, and Schwann Cells
What are Oligodendrocytes and Schwann Cells?
The two types of glial cells that form myelin sheaths around axons.
What is Myelin?
A white, fatty substance found in the myelin sheath around some nerve fibers.
What does the Myelin Sheath do?
Insulated the axon of some neurons and helps speed neural impulses
What are Astrocytes?
They are the MOST NUMEROUS GLIAL CELL, they fill spaces between neurons for
support, and regulate the composition of the extracellular space. It is important to note
that Astrocytes form a connection between neurons and capillaries. Astrocytes are
ONLY found in the brain.
They do everything except conduct action potentials.
What do Glial Cells do? What is the one thing they do NOT do?
They Support and protect neurons. They do NOT conduct action potentials.
Which glial cell produces myelination in the PNS?
Schwann Cells (1 cell myelinates 1 axon segment)
Which glial cell produces myelination in the CNS?
Oligodendrocytes (1 cell myelinates many axons)
What is Electrostatic Pressure?
,Causes ions to flow towards oppositely charged areas.
Like charges repel, opposites attract - ions move to balance the charge
What is Diffusion?
The movement of particles from an area of high concentration to an area of low
concentration.
Think: DIFFusion = DIFFerence in concentration drives flow
What do diffusion and electrostatic pressure form together?
The electrochemical gradient. (Concentration and Charge forces acting at once)
We use what two main processes for ATP? What are the pros and cons for each?
Glycolysis and The Krebs Cycle
Glycolysis doesnt produce as much ATP, but it is the more efficient one. The Krebs
Cycle produces an abundant amount of ATP, however it is not as efficient and requires
a lot more.
What does electrostatic diffusion do to potassium ions (K+)?
Potassium (K+) is high inside: Diffusion pushes out, electrostatic pulls in (inside is -)
What does electrostatic diffusion do to sodium ions (Na+)?
Sodium (Na+) is high outside: both forces push it in
What does electrostatic diffusion do to chloride ions (Cl-)?
Chloride (Cl-) is high outside: Diffusion in, electrostatic (inside is -) pushes it out -> the
net depends on channels
What is Depolarization?
The inside of the membrane becomes less negative and more positive.
This term refers to when any time the charge difference becomes more positive than the
RPM of - 70mV. moving closer to zero.
What is hyperpolarization?
membrane potential becomes more negative
What does depolarization do?
Opens Na+ channels and makes it more likely to fire an action potential
What does Hyperpolarization do?
An increase in the membrane potential of a cell, relative to the normal resting potential.
Makes it less likely that a nerve impulse (action potential) will fire.
What are Cable Properties?
The passive conduction of electrical current, in a gradual decrease, down the length of
an axon.
What is the purpose for Cable Properties?
Dendrites dont have action potentials, the have cable properties.
How do Cable Properties compare to Action Potentials?
Cable properties are good for short distances, they are fast, and they dont require a lot
of energy. However, there is a limited distance to which they can travel (only short
distances), and only one intensity.
Action Potentials require more energy but they can travel further, and they have a
stronger intensity (all or none).
, What is an Action Potential?
An electrical impulse that travels down the axon triggering the release of
neurotransmitters
How is an Action Potential generated?
As an action potential travels down the axon, there is a change in polarity across the
membrane. The Na+ and K+ gated ion channels open and close as the membrane
reaches the threshold potential, in response to a signal from another neuron.
What is the threshold of excitation?
The value of the membrane potential that must be reached to produce an action
potential. (-55mV)
There is no ______ of action potentials, why is this?
Intensity. This is because of the all or none principle.
What is the All or None Law of an Action Potential?
The principle that once an action potential is triggered in an axon, it is propagated,
without slowing down, to the end of the fiber. It gives it ALL or NOTHING. There is no
level of intensity.
What is an Ion (Ligand-Gated) Channel?
It is a specialized protein molecule that permits specific ions to enter or leave the cells.
They open when a neurotransmitter binds.
What is a Voltage-dependent ion channel?
an ion channel that opens or closes according to the value of the membrane voltage
(Na+, K+, Ca2+)
What are two types of voltage-dependent channels?
Sodium and Potassium
The Sodium Channel is activated by ______ and stays open based on _____.
Voltage; Time
Once activated by voltage, the sodium channel has a limited time that is stays open.
This is like flipping a sand timer upside down.
The Potassium Channel is activated by ______ and stays open based on _____.
Voltage; Voltage
Once activated by voltage, the potassium channel will remain open as long as the
voltage is above the threshold for an action potential. If it is below, the channel will
close.
What is the purpose of the sodium-potassium transporter?
Neurons fire multiple action potentials at a time which means a lot of sodium will begin
to accumulate in the cell, which will depolarize it. The solution for this is the sodium-
potassium transporter because it allows 1 K+ in for every 3 Na+ out. It prevents the
build up of sodium in the cell.
When will sodium stop entering the cell?
When the equilibrium gets off balance (the cell gets too positive) or when the channel
closes (its on a timer)
What is the Sodium-Potassium Transporter?
A protein found in the membrane of all cells that extrudes sodium ions from and
transports potassium ions into the cell.
