Science Biology Neuroscience
BIOL 252 Exam 1
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PN Adult Medical Surgical Online Pr... Glaziers review test Exam 2 (Chapter 4, 5, 7, 10, 14, 17) ATI PN
90 terms 124 terms 308 terms Teacher
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Explain the functional divisions of the nervous system. Central Nervous System and Peripheral Nervous System
Include the subdivisions of each. - CNS includes the brain and spinal cord
- PNS includes autonomic and somatic nervous systems
Are thermoreceptors part of the PNS or CNS? PNS
A child eats a whole bottle of salt (NaCl) tablets. What no effect - think of the analogy of adding a handful of sand to the beach. The
effect does this have on the resting membrane potential? concentration of Na+ outside the cell is already very high at the resting potential,
so adding a (relatively) small amount will not have an effect on resting potential
Why are potassium ions the major factors that determine cell membranes are more permeable to K+ than to other ions (via potassium leak
the resting membrane potential? channels)
Define leak and gated ion channels. How are they Leak channels - membrane channels with no gating mechanism; due to the
responsible for the permeability characteristics of a size/shape of the membrane protein, each is only permeable to specific ions;
resting versus a stimulated plasma membrane? form of passive transport, as they allow ions to diffuse down their concentration
gradients
Gated ion channels - membrane channels with a gating mechanism such as
voltage or ligands; opening of these channels stimulated by the binding of a
particular ligand or changes in cell voltage; once these channels are open, ions
can diffuse down their concentration gradient (passive transport); ion specific
Leak channels always allow diffusion (both resting and stimulated membranes);
gated-channels are only permeable when the membrane is stimulated in a
specific way
, If you decrease the K+ concentration outside of the cell hyperpolarization
(hypokalemia), would lead to hyper- or de- polarization?
Decreasing the K+ concentration outside the cell would cause K+ to leak out from
inside the cell via the potassium leak channels. This would further polarize the
charge difference between the inside and outside of the cell, making the inside
more negative relative to the outside of the cell.
Define action potential. How do depolarizing and Action potential - change in electrical potential; generated at the axon hillock
hyperpolarizing graded potentials affect the likelihood of when a stimulus passes a threshold
generating an action potential?
Depolarizing graded potentials (e.g. EPSPs) increases the likelihood of generating
an action potential because it brings the resting potential closer to the level of
the threshold;
Hyperpolarizing graded potentials (e.g. IPSPs) reduces the likelihood of
generating an action potential because it brings the resting potential farther from
the threshold.
Why is action potential considered to be an all-or-non A certain threshold of depolarization must be crossed by the neuron before an
phenomenon? action potential is generated; if the charge reaches halfway to the threshold, there
will be no action potential, NOT half an action potential
An action potential does not get smaller as it propagates. voltage-gated ion channels along the membrane of the axon (or in the nodes of
Why? Ranvier of myelinated axons) essentially allow for the regeneration of
local/graded potentials as the AP travels down the axon;
in myelinated cells, action potentials undergo saltatory conduction in which the
segments of myelin insulate the axon and prevent the charge from dispersing, and
the intermediate nodes of Ranvier are packed with voltage-gated ion channels.
A stronger stimulus cannot generate a greater action Because action potentials are "all-or-nothing," a stimulus stronger than the
potential, but it can increase the frequency of action threshold will not generate an action potential stronger than the average;
potentials generated in the trigger zone. Explain instead, the frequency of action potentials is proportional to the strength of the
stimulus, because action potentials can occur more frequently if there is a
constant source of stimulus as long as the relative refractory period is achieved
How do EPSPs and IPSPs affect the likelihood of EPSPs - increase the likelihood
generating an action potential? - EPSPs are excitatory signals, and result in depolarizing, increasing the likelihood
of an action potential;
IPSPs - decrease the likelihood
- IPSPs are inhibitory signals, and result in hyperpolarization, decreasing the
likelihood of an action potential
How does location of voltage-gated Na+ channels differ In a myelinated axon, voltage-gated Na+ channels are concentrated/packed into
between a myelinated axon and an unmyelinated axon? the nodes of Ranvier (spaces between segments of myelination);
In unmyelinated axons, voltage-gated Na+ channels are spread throughout the
length of the axon
BIOL 252 Exam 1
Save
Students also studied
PN Adult Medical Surgical Online Pr... Glaziers review test Exam 2 (Chapter 4, 5, 7, 10, 14, 17) ATI PN
90 terms 124 terms 308 terms Teacher
sugarDee2 Preview Steph3797 Preview marrininnis Preview CA
Explain the functional divisions of the nervous system. Central Nervous System and Peripheral Nervous System
Include the subdivisions of each. - CNS includes the brain and spinal cord
- PNS includes autonomic and somatic nervous systems
Are thermoreceptors part of the PNS or CNS? PNS
A child eats a whole bottle of salt (NaCl) tablets. What no effect - think of the analogy of adding a handful of sand to the beach. The
effect does this have on the resting membrane potential? concentration of Na+ outside the cell is already very high at the resting potential,
so adding a (relatively) small amount will not have an effect on resting potential
Why are potassium ions the major factors that determine cell membranes are more permeable to K+ than to other ions (via potassium leak
the resting membrane potential? channels)
Define leak and gated ion channels. How are they Leak channels - membrane channels with no gating mechanism; due to the
responsible for the permeability characteristics of a size/shape of the membrane protein, each is only permeable to specific ions;
resting versus a stimulated plasma membrane? form of passive transport, as they allow ions to diffuse down their concentration
gradients
Gated ion channels - membrane channels with a gating mechanism such as
voltage or ligands; opening of these channels stimulated by the binding of a
particular ligand or changes in cell voltage; once these channels are open, ions
can diffuse down their concentration gradient (passive transport); ion specific
Leak channels always allow diffusion (both resting and stimulated membranes);
gated-channels are only permeable when the membrane is stimulated in a
specific way
, If you decrease the K+ concentration outside of the cell hyperpolarization
(hypokalemia), would lead to hyper- or de- polarization?
Decreasing the K+ concentration outside the cell would cause K+ to leak out from
inside the cell via the potassium leak channels. This would further polarize the
charge difference between the inside and outside of the cell, making the inside
more negative relative to the outside of the cell.
Define action potential. How do depolarizing and Action potential - change in electrical potential; generated at the axon hillock
hyperpolarizing graded potentials affect the likelihood of when a stimulus passes a threshold
generating an action potential?
Depolarizing graded potentials (e.g. EPSPs) increases the likelihood of generating
an action potential because it brings the resting potential closer to the level of
the threshold;
Hyperpolarizing graded potentials (e.g. IPSPs) reduces the likelihood of
generating an action potential because it brings the resting potential farther from
the threshold.
Why is action potential considered to be an all-or-non A certain threshold of depolarization must be crossed by the neuron before an
phenomenon? action potential is generated; if the charge reaches halfway to the threshold, there
will be no action potential, NOT half an action potential
An action potential does not get smaller as it propagates. voltage-gated ion channels along the membrane of the axon (or in the nodes of
Why? Ranvier of myelinated axons) essentially allow for the regeneration of
local/graded potentials as the AP travels down the axon;
in myelinated cells, action potentials undergo saltatory conduction in which the
segments of myelin insulate the axon and prevent the charge from dispersing, and
the intermediate nodes of Ranvier are packed with voltage-gated ion channels.
A stronger stimulus cannot generate a greater action Because action potentials are "all-or-nothing," a stimulus stronger than the
potential, but it can increase the frequency of action threshold will not generate an action potential stronger than the average;
potentials generated in the trigger zone. Explain instead, the frequency of action potentials is proportional to the strength of the
stimulus, because action potentials can occur more frequently if there is a
constant source of stimulus as long as the relative refractory period is achieved
How do EPSPs and IPSPs affect the likelihood of EPSPs - increase the likelihood
generating an action potential? - EPSPs are excitatory signals, and result in depolarizing, increasing the likelihood
of an action potential;
IPSPs - decrease the likelihood
- IPSPs are inhibitory signals, and result in hyperpolarization, decreasing the
likelihood of an action potential
How does location of voltage-gated Na+ channels differ In a myelinated axon, voltage-gated Na+ channels are concentrated/packed into
between a myelinated axon and an unmyelinated axon? the nodes of Ranvier (spaces between segments of myelination);
In unmyelinated axons, voltage-gated Na+ channels are spread throughout the
length of the axon
