TTU BIO 2 EXAM 4 QUESTIONS AND
ANSWERS
What function does myelin serve? -
correct answer ✅It is a specialized cell wrapped around an axon
that increases the speed of neural signals
How does myelin speed up neurotransmitting? -
correct answer ✅It forms a myelin sheath around an axon, which
acts as electrical insulation, it prevents ions from leaking out across
the plasma membrane during the propagation of an action
potential
What happens when an action potential reaches the end of an
axon? -
correct answer ✅It reaches the synapse, which is a tiny space
between neurons, and the signal continues through a
neurotransmitter
What is a neurotransmitter -
correct answer ✅chemical messenger that travels form one
neuron to another neuron, muscle, or gland (supported by Otto
Loewi's experiments with frogs)
Explain the difference between excitatory postsynaptic potentials
(EPSPs) & inhibitory (IPSPs) -
,TTU BIO 2 EXAM 4 QUESTIONS AND
ANSWERS
correct answer ✅EPSPs cause membrane to depolarize, increasing
likelihood of an action potential. IPSPs cause membrane to be
hyperpolarized, decreasing likelihood of an action potential
How does an EPSP cause depolarization of cell membrane? -
correct answer ✅When neurotransmitter binds, it opens ligand
gated sodium channels on membranes of dendrites that open and
allow sodium to enter the cell, causing depolarization
How does an IPSP cause hyperpolarization? -
correct answer ✅If neurotransmitter binding leads to an outflow
of potassium ions or anions, postsynaptic membrane
hyperpolarizes
T/F: One EPSP causes an action potential -
correct answer ✅FALSE, the sum of several EPSP's make a neuron
likely to fire an action potential. The more EPSP's, the higher the
action potential. The additive nature of postsynaptic potentials is
called summation
Explain the three parts of all vertebrate brains and their functions -
correct answer ✅Forebrain (smell), Midbrain (vision), Hindbrain
(hearing and sometimes balance)
, TTU BIO 2 EXAM 4 QUESTIONS AND
ANSWERS
Explain how the node of ranvier relates to myelination -
correct answer ✅The node of ranvier is the gap in myelin sheath, it
has a dense concentration of voltage gated Na+ and K+ channels, so
new action potentials can be generated. These action potentials
"jump" from node to node down a myelinated axon much faster
than with an unmyelinated axon.
What happens when an EPSP and IPSP occur at the same time? -
correct answer ✅They can cancel each other out
Explain how the synaptic cleft, synaptic vesicles, presynaptic
neuron, and postsynaptic cell are involved in neurotransmitting -
correct answer ✅The synaptic cleft is the tiny space between
axons and cells. The end of axons contain synaptic vesicles that
store neurotransmitters. At the synapse. the cells that contains the
synaptic vesicles is called the presynaptic neuron, and the cell on
the other side of the cleft is the postsynaptic cell.
T/F: EPSPs and IPSPs are short-term events because they do not
bind irreversibly to receptors -
correct answer ✅TRUE. The magnitude of an EPSP or IPSP
ANSWERS
What function does myelin serve? -
correct answer ✅It is a specialized cell wrapped around an axon
that increases the speed of neural signals
How does myelin speed up neurotransmitting? -
correct answer ✅It forms a myelin sheath around an axon, which
acts as electrical insulation, it prevents ions from leaking out across
the plasma membrane during the propagation of an action
potential
What happens when an action potential reaches the end of an
axon? -
correct answer ✅It reaches the synapse, which is a tiny space
between neurons, and the signal continues through a
neurotransmitter
What is a neurotransmitter -
correct answer ✅chemical messenger that travels form one
neuron to another neuron, muscle, or gland (supported by Otto
Loewi's experiments with frogs)
Explain the difference between excitatory postsynaptic potentials
(EPSPs) & inhibitory (IPSPs) -
,TTU BIO 2 EXAM 4 QUESTIONS AND
ANSWERS
correct answer ✅EPSPs cause membrane to depolarize, increasing
likelihood of an action potential. IPSPs cause membrane to be
hyperpolarized, decreasing likelihood of an action potential
How does an EPSP cause depolarization of cell membrane? -
correct answer ✅When neurotransmitter binds, it opens ligand
gated sodium channels on membranes of dendrites that open and
allow sodium to enter the cell, causing depolarization
How does an IPSP cause hyperpolarization? -
correct answer ✅If neurotransmitter binding leads to an outflow
of potassium ions or anions, postsynaptic membrane
hyperpolarizes
T/F: One EPSP causes an action potential -
correct answer ✅FALSE, the sum of several EPSP's make a neuron
likely to fire an action potential. The more EPSP's, the higher the
action potential. The additive nature of postsynaptic potentials is
called summation
Explain the three parts of all vertebrate brains and their functions -
correct answer ✅Forebrain (smell), Midbrain (vision), Hindbrain
(hearing and sometimes balance)
, TTU BIO 2 EXAM 4 QUESTIONS AND
ANSWERS
Explain how the node of ranvier relates to myelination -
correct answer ✅The node of ranvier is the gap in myelin sheath, it
has a dense concentration of voltage gated Na+ and K+ channels, so
new action potentials can be generated. These action potentials
"jump" from node to node down a myelinated axon much faster
than with an unmyelinated axon.
What happens when an EPSP and IPSP occur at the same time? -
correct answer ✅They can cancel each other out
Explain how the synaptic cleft, synaptic vesicles, presynaptic
neuron, and postsynaptic cell are involved in neurotransmitting -
correct answer ✅The synaptic cleft is the tiny space between
axons and cells. The end of axons contain synaptic vesicles that
store neurotransmitters. At the synapse. the cells that contains the
synaptic vesicles is called the presynaptic neuron, and the cell on
the other side of the cleft is the postsynaptic cell.
T/F: EPSPs and IPSPs are short-term events because they do not
bind irreversibly to receptors -
correct answer ✅TRUE. The magnitude of an EPSP or IPSP
