PNB Exam 3 questions n answers
graded A+ latest update
Can you label the anatomy of a neuron and match each region to its function? - ANS
✔✔Dendrites: Signal input: Increase density of receptors to receive signals from
internal/external environment
Cell body: (Soma); High density of ribosomes for protein synthesis also have lots of
mitochondria
Axon: Action potentials are sent through the axons. Neurons only have one axon or none at all
Axon Terminal: Forms synapse with another cell
Do you know the terms used to describe changes in membrane potential? - ANS
✔✔Depolarization: A positive change in membrane potential
Hyperpolarization: When membrane experiences negative membrane potential
Repolarization: When membrane returns to rest
Can you describe how different regions of the cell generate and propagate electrical signals? -
ANS ✔✔Axon terminal of a neuron sends a message. Plasma membrane of a dendrite will
receive a message. (Presynaptic neuron sends a signal to a post synaptic neuron) Neuron
receiving will have a ligand channel on dendrite to bind neurotransmitters causing membrane
potential changes called Synaptic potential
• Are you able to describe a typical axon segment? - ANS ✔✔typically conducts electrical
impulses known as action potentials away from the nerve cell body. The function of the axon is
to transmit information to different neurons, muscles, and glands.
• Can you compare and contrast graded potential and action potentials? - ANS ✔✔Graded
potentials: changes in membrane potential have varying amplitude (can be weak or strong) and
decremental
, Action potentials are not decremental and maintain strength over time- begin at axon hillock
due to high density of voltage gated sodium channels
• Do you know the general characteristics of nervous tissue? - ANS ✔✔
• Can you explain the function and origin of myelin? - ANS ✔✔Myelin is created by supporting
cells ("Glial cells") and keeps current from dissipating (think of electrical wires)
Allows for further and faster propagation and depolarization (fewer ion channels are needed in
internodes)
• Are you able to predict how changes in ion concentration will impact the action potential? -
ANS ✔✔If potassium channels in the membrane open it will begin to move down its
concentration gradient and out of the cell. When ion leaves the cell, the cell's interior loses a
positive charge. (Hyperpolarization)
Na will try to drag the membrane potential toward its (positive) equilibrium potential.
(Depolarization)
• Are you able to predict how changes in permeability will impact membrane potential? - ANS
✔✔Sodium entering the cell will make the cell more positive, causing depolarization if
Potassium enters the cell it will experience a negative change
• Can you relate structural changes in ion channels to changes in neuron function? - ANS
✔✔controlled by proteins that can change shape to open or close the channel in response to
various signals.
• Are you able to explain the effects of channelopathies on nervous tissue function and provide
examples? - ANS ✔✔Channelopathies are diseases caused by disturbed function of ion channel
subunits or the proteins that regulate them.
astrocytes, microglial cells, ependymal cells, and oligodendrocytes
graded A+ latest update
Can you label the anatomy of a neuron and match each region to its function? - ANS
✔✔Dendrites: Signal input: Increase density of receptors to receive signals from
internal/external environment
Cell body: (Soma); High density of ribosomes for protein synthesis also have lots of
mitochondria
Axon: Action potentials are sent through the axons. Neurons only have one axon or none at all
Axon Terminal: Forms synapse with another cell
Do you know the terms used to describe changes in membrane potential? - ANS
✔✔Depolarization: A positive change in membrane potential
Hyperpolarization: When membrane experiences negative membrane potential
Repolarization: When membrane returns to rest
Can you describe how different regions of the cell generate and propagate electrical signals? -
ANS ✔✔Axon terminal of a neuron sends a message. Plasma membrane of a dendrite will
receive a message. (Presynaptic neuron sends a signal to a post synaptic neuron) Neuron
receiving will have a ligand channel on dendrite to bind neurotransmitters causing membrane
potential changes called Synaptic potential
• Are you able to describe a typical axon segment? - ANS ✔✔typically conducts electrical
impulses known as action potentials away from the nerve cell body. The function of the axon is
to transmit information to different neurons, muscles, and glands.
• Can you compare and contrast graded potential and action potentials? - ANS ✔✔Graded
potentials: changes in membrane potential have varying amplitude (can be weak or strong) and
decremental
, Action potentials are not decremental and maintain strength over time- begin at axon hillock
due to high density of voltage gated sodium channels
• Do you know the general characteristics of nervous tissue? - ANS ✔✔
• Can you explain the function and origin of myelin? - ANS ✔✔Myelin is created by supporting
cells ("Glial cells") and keeps current from dissipating (think of electrical wires)
Allows for further and faster propagation and depolarization (fewer ion channels are needed in
internodes)
• Are you able to predict how changes in ion concentration will impact the action potential? -
ANS ✔✔If potassium channels in the membrane open it will begin to move down its
concentration gradient and out of the cell. When ion leaves the cell, the cell's interior loses a
positive charge. (Hyperpolarization)
Na will try to drag the membrane potential toward its (positive) equilibrium potential.
(Depolarization)
• Are you able to predict how changes in permeability will impact membrane potential? - ANS
✔✔Sodium entering the cell will make the cell more positive, causing depolarization if
Potassium enters the cell it will experience a negative change
• Can you relate structural changes in ion channels to changes in neuron function? - ANS
✔✔controlled by proteins that can change shape to open or close the channel in response to
various signals.
• Are you able to explain the effects of channelopathies on nervous tissue function and provide
examples? - ANS ✔✔Channelopathies are diseases caused by disturbed function of ion channel
subunits or the proteins that regulate them.
astrocytes, microglial cells, ependymal cells, and oligodendrocytes
