CBNS 120 MIDTERM 2 REVIEW QUESTIONS WITH
VERIFIED ANSWERS
Activation of the GIRK channel makes the Vm - Answers - Negative
G protein inhibition of calcium current is state dependent. - Answers - True
PIP2 splits into what two secondary messengers? - Answers - IP3 (inositol triphosphate)
and DAG (diacylglycerol)
What does IP3 activate? - Answers - Ca2+ from intracellular stores
M-current K+ channel: - Answers - Decreases membrane excitability
Which cells originate in the brain? - Answers - Astrocytes and oligodendrocytes
Glial cells: - Answers - -Buffer extracellular [K]
-Depolarise in response to neuronal activity
-Recycle neurotransmitters
Astrocytes: - Answers - -Respond to neurotransmitters
-Release neurotransmitters
-Regulate blood flow
Dye coupling occurs: - Answers - -in neurons
-in astrocytes
-due to the presence of gap junctions
Cell types responsible for myelination: - Answers - -Schwann cells
-Oligodendrocytes
At physiological membrane potentials (-60mv to -80mV) the motor endplate current is
carried predominantly by: - Answers - Na
At vertebrate neuromuscular synapse, reversal potential (Eepc) is approximately equal
to: - Answers - ENa - EK
When extracellular [Cl] is replaced by isethionate, glycine application to a lamprey
brainstem neuron leads to: - Answers - increased permeability and no change in input
resistance
At hippocampal GABAergic synapses, autoinhibition is mediated by: - Answers -
GABAb receptors and the inhibition of presynaptic voltage-gated calcium channels
, At hippocampal glutamatergic synapses, where the postsynaptic membrane potential is
-80mV: - Answers - -postsynaptic current is inward
-postsynaptic current is sensitive to CNQX
-postsynaptic current flows exclusively through AMPA channels
At the vertebrate neuromuscular junction, when the postsynaptic membrane potential is
stepped to more positive values, as the membrane potential approaches 0mV: -
Answers - - EPC amplitude decreases and EPC reverses from inward to outward when
Em becomes more positive than Eepc
Astrocytes contribute to synapse formation via: - Answers - - secretion of Hevin
- secretion of thrombospondins (TSPs)
Glial cells respond to neuronal activity by - Answers - depolarising
Glial cells: - Answers - -release ATP through hemi-connexons
-release glutamate through reversal of transporter activity
-release D-serine at synapses
NMDA receptors: - Answers - -respond to glutamate
-are blocked at negative potentials by magnesium
-require depolarisation to conduct inward current
Gap junctions (communicating junctions): - Answers - -are cytoplasmic bridges
-occur at electronic synapses
IPSPs: - Answers - -are hyperpolarising membrane recpetors
-result from an increase in chloride conductance
The EPP at the vertebrate neuromuscular junction: - Answers - -is a passive membrane
response
-always exceeds threshold under natural conditions
Endocannabinoids: - Answers - Anadamide, 2-AG
The minutes long late-slow EPSP observed in sympathetic ganglion neurons results
from: - Answers - -reduced probability of M channel opening
-reduced membrane conductance
-dissociation of PIP2 from the M channel
Vagal nerve mediated parasympathetic input to the heart causes: - Answers - slowing of
the heart beat and reduction of cAMP
The following contribute to elevation of cytoplasmic calcium levels: - Answers - HCN
activation and activation of Gq
VERIFIED ANSWERS
Activation of the GIRK channel makes the Vm - Answers - Negative
G protein inhibition of calcium current is state dependent. - Answers - True
PIP2 splits into what two secondary messengers? - Answers - IP3 (inositol triphosphate)
and DAG (diacylglycerol)
What does IP3 activate? - Answers - Ca2+ from intracellular stores
M-current K+ channel: - Answers - Decreases membrane excitability
Which cells originate in the brain? - Answers - Astrocytes and oligodendrocytes
Glial cells: - Answers - -Buffer extracellular [K]
-Depolarise in response to neuronal activity
-Recycle neurotransmitters
Astrocytes: - Answers - -Respond to neurotransmitters
-Release neurotransmitters
-Regulate blood flow
Dye coupling occurs: - Answers - -in neurons
-in astrocytes
-due to the presence of gap junctions
Cell types responsible for myelination: - Answers - -Schwann cells
-Oligodendrocytes
At physiological membrane potentials (-60mv to -80mV) the motor endplate current is
carried predominantly by: - Answers - Na
At vertebrate neuromuscular synapse, reversal potential (Eepc) is approximately equal
to: - Answers - ENa - EK
When extracellular [Cl] is replaced by isethionate, glycine application to a lamprey
brainstem neuron leads to: - Answers - increased permeability and no change in input
resistance
At hippocampal GABAergic synapses, autoinhibition is mediated by: - Answers -
GABAb receptors and the inhibition of presynaptic voltage-gated calcium channels
, At hippocampal glutamatergic synapses, where the postsynaptic membrane potential is
-80mV: - Answers - -postsynaptic current is inward
-postsynaptic current is sensitive to CNQX
-postsynaptic current flows exclusively through AMPA channels
At the vertebrate neuromuscular junction, when the postsynaptic membrane potential is
stepped to more positive values, as the membrane potential approaches 0mV: -
Answers - - EPC amplitude decreases and EPC reverses from inward to outward when
Em becomes more positive than Eepc
Astrocytes contribute to synapse formation via: - Answers - - secretion of Hevin
- secretion of thrombospondins (TSPs)
Glial cells respond to neuronal activity by - Answers - depolarising
Glial cells: - Answers - -release ATP through hemi-connexons
-release glutamate through reversal of transporter activity
-release D-serine at synapses
NMDA receptors: - Answers - -respond to glutamate
-are blocked at negative potentials by magnesium
-require depolarisation to conduct inward current
Gap junctions (communicating junctions): - Answers - -are cytoplasmic bridges
-occur at electronic synapses
IPSPs: - Answers - -are hyperpolarising membrane recpetors
-result from an increase in chloride conductance
The EPP at the vertebrate neuromuscular junction: - Answers - -is a passive membrane
response
-always exceeds threshold under natural conditions
Endocannabinoids: - Answers - Anadamide, 2-AG
The minutes long late-slow EPSP observed in sympathetic ganglion neurons results
from: - Answers - -reduced probability of M channel opening
-reduced membrane conductance
-dissociation of PIP2 from the M channel
Vagal nerve mediated parasympathetic input to the heart causes: - Answers - slowing of
the heart beat and reduction of cAMP
The following contribute to elevation of cytoplasmic calcium levels: - Answers - HCN
activation and activation of Gq
