Questions Flashcards
Afferent and efferent are terms:
a. For neurons always found only in the Central Nervous System.
b. For neurons that carry information between each other.
c. For the parts of neurons where most inputs occur.
d. To describe whether a neuron is conducting information to or from the CNS.
e. To describe the integrative and conducting parts of a neuron.
Afferent and efferent are terms:
d. To describe whether a neuron is conducting information to or from the CNS.
Afferent = sensory nerves that carry nerve impulses from sensory stimuli to the CNS. Efferent carries nerve impulses from CNS to muscle to stimulate movement
Gating of an ion channel
a. Depends on the type of ion that moves through the channel.
b. Is controlled by chemicals, voltage or membrane stress.
c. Will determine whether there is a concentration gradient for the ion that moves through the channel.
d. Will determine whether there is an electrical gradient for the ion that moves through the channel.
e. Will be determined by where the ion channel is located on the dendrites.
Gating of an ion channel
b. Is controlled by chemicals, voltage or membrane stress.
Gating is the closing or activation of ion channels
Gating of an ion channel means that:
a. movement of ions through the channel is always passive.
b. the channel is selective as to which ions move through.
c. the opening or closing of the channel is controlled.
d. the channel is always responsible for producing Action Potentials.
e. the opening or closing of the channel depends on the electro-chemical gradients for that ion.
Gating of an ion channel means that:
c. the opening or closing of the channel is controlled.
Integration of the different inputs that a neuron receives:
a. Always occurs at the dendrites of a neuron.
b. Depends on whether the neuron is myelinated or unmyelinated.
c. Generally occurs along the axon of a neuron.
d. Generally occurs at the axon hillock of a neuron.
e. Depends on whether the neuron has microtubules or dendrites.
Integration of the different inputs that a neuron receives:
d. Generally occurs at the axon hillock of a neuron.
Dendrites collect info
Axon hillock integrates inco
Axon carries info
Synapse transmits info
Interneurons:
a. transmit information to directly control skeletal muscle.
b. are the regions of a neuron where other neurons make contact (synapse).
c. are the regions of a neuron through which ions can cross the membrane.
d. transmit information from one neuron to another.
e. transmit information between neurons only over short distances.
Interneurons
d. transmit information from one neuron to another.
Interneurons are found in the CNS only, not the peripheral nervous system.
In the CNS, a nucleus is:
a. a collection of nerve axons carrying information from the peripheral nervous system to the CNS.
b. a collection of nerve cell bodies.
c. a collection of ganglia.
d. the structure that provides support to neurons.
e. responsible for providing the myelin sheath around the axon of neurons.
In the CNS, a nucleus is:
b. a collection of nerve cell bodies.
Ganglia contain nerve cell bodies and glial cells
The dendrites of a neuron are:
a. the cytoplasmic extensions of the cell body at which neurons receive most of their inputs.
b. the output functional component of a neuron and the sites where chemicals are released.
c. the regions of a myelinated neuron which are sheathed by Schwann cells.
d. the sites at which a neuron integrates inputs.
e. the structures that give rigidity to the cell body.
The dendrites of a neuron are:
a. the cytoplasmic extensions of the cell body at which neurons receive most of their inputs.
Dendrites can be used to categorise neurons
Usually, dendrites that branch out more tell us that it is located in an area where there is a lot of information input, such as the eye.
The two types of cells of the nervous system are called:
a. neurons and ganglia cells.
b. nuclei and ganglia cells.
c. neurons and glial cells.
d. afferent and efferent cells.
e. somatic and autonomic cells.
The two types of cells of the nervous system are called:
c. neurons and glial cells.
ganglia = plural of ganglion
= nerve cluster of glia + neurons
glia = oligdendria, schwann, microglia, astrocytes, epidural (for CSF)
Unmyelinated axons differ from myelinated axons in that unmyelinated axons:
a. are not associated with Schwann cells.
b. are always larger so that they can transmit action potentials more quickly.
c. transmit action potentials by saltatory conduction.
d. do not have dendrites or axon hillocks.
e. do not have nodes of Ranvier.
Unmyelinated axons differ from myelinated axons in that unmyelinated axons:
e. do not have nodes of Ranvier
Nodes of Ranvier are found between sections of myelin sheath
Which one of the following statements is CORRECT?
a. Movement of ions through gated ion channels always is a passive process that does not require energy expenditure.
b. Gated ion channels are only those channels associated with the active pump.
c. Gated ion channels are integral membrane carbohydrates.
d. Gated ion channels are only those ion channels that can be made refractory.
e. Gated ion channels are always so selective that they allow only one type of ion to pass through.
Which one of the following statements is CORRECT?
a. Movement of ions through gated ion channels always is a passive process that does not require energy expenditure.
At a chemical synapse:
a. action potentials are produced by chemical vesicles.
b. binding of chemicals to receptors causes the opening of voltage-gated vesicles in the post-synaptic cell.
c. pre-synaptic terminal depolarisation ultimately causes release of chemicals from vesicles.
d. transmission of activity from pre-synaptic to post-synaptic cells occurs through second messengers.
e. second messengers allow the binding of vesicles to the pre-synaptic membrane.
At a chemical synapse:
c. pre-synaptic terminal depolarisation ultimately causes release of chemicals from vesicles.
Vesicles release info containing AP, but do not produce it. APs are produced by different ions across neuronal membrane.
Second messengers are molecules that relay signals received at the post synaptic terminal. They are extracellular factors, and are often hormones or neurotransmitters.
At the post-synaptic cell, neurotransmitters produce voltage changes:
a. only by binding to membrane-bound receptors that form ion channels.
b. only by binding to receptors that are protein complexes made up of five sub-units.
c. that are always a depolarization of the post-synaptic resting membrane potential.
d. that may be a depolarization or a hyper-polarization of the post-synaptic resting membrane potential.
e. through receptors that selectively allow the movement of only one ion.
At the post-synaptic cell, neurotransmitters produce voltage changes:
d. that may be a depolarization or a hyper-polarization of the post-synaptic resting membrane potential.
Peptidergic synapses differ from non-petidergic synapses in that:
a. Peptidergic synapses do not store transmitter in vesicles.
b. Peptidergic synapses have few vesicles of transmitter docked at the docking proteins at the active zone.
c. Peptidergic synapses transmit information more efficiently.
d. Peptidergic synapses synthesize transmitter in the terminal and vesicles in the cell body.
e. Peptidergic synapses do not require terminal depolarization for synaptic transmission.
Peptidergic synapses differ from non-petidergic synapses in that:
b. Peptidergic synapses have few vesicles of transmitter docked at the docking proteins at the active zone.
Peptidergic = neurons that secrete peptides
Which of the following statements about terminating neurotransmitter action is CORRECT?
a. The actions of some neurotransmitters are terminated by re-uptake of the chemical into the terminal.
b. The actions of all neurotransmitters are terminated by degradation by enzymes within the synaptic cleft.
c. The actions of some neurotransmitters are terminated by simple diffusion of the chemical back into the pre-synaptic terminal.
d. The actions of some neurotransmitters are terminated by binding of the chemical to G proteins in the pre-synaptic terminal.
e. The actions of all neurotransmitters are terminated by re-uptake of the chemical into glial cells.
Which of the following statements about terminating neurotransmitter action is CORRECT?
a. The actions of some neurotransmitters are terminated by re-uptake of the chemical into the terminal.
Which of the following statements about vesicle fusion and transmitter release is INCORRECT?
a. Only vesicles bound to docking proteins can fuse with the pre-synaptic membrane.
b. Vesicle fusion with the terminal membrane can occur only in the region of the active zones.
c. Calcium entry into the terminal occurs only through voltage-gated channels.
d. Voltage-gated calcium channels are found across the entire surface of the terminal.
e. After fusion with the terminal membrane and release of neurotransmitter, the vesicle membrane is recycled within the terminal.
Which of the following statements about vesicle fusion and transmitter release is INCORRECT?
d. Voltage-gated calcium channels are found across the entire surface of the terminal.
Which of the following statements comparing transmitter-gated channels and voltage-gated channels is CORRECT?
a. Transmitter-gated channels are as selective for ions as are voltage-gated channels.
b. Transmitter-gated channels and voltage-gated channels always produce a depolarisation.
c. Transmitter-gated channels and voltage-gated channels always have a central water-filled pore allowing ionic movement.
d. Transmitter-gated channels and voltage-gated channels can produce fast voltage changes or slow effects through G proteins.
e. Transmitter-gated channels and voltage-gated channels are both controlled by the trans-membrane potential difference
Which of the following statements comparing transmitter-gated channels and voltage-gated channels is CORRECT?
c. Transmitter-gated channels and voltage-gated channels always have a central water-filled pore allowing ionic movement.
Which ONE is INCORRECT for the receptors involved in fast synaptic transmission?
a. Different receptors are needed for binding different neurotransmitters.
b. They always contain a water-filled pore that acts as an ion channel.
c. They are always a protein complex made up of five identical sub-units.
d. A second messenger is not required for the post-synaptic effect.
e. These receptors can produce fast excitatory or inhibitory post-synaptic potentials.
Which ONE is INCORRECT for the receptors involved in fast synaptic transmission?
c. They are always a protein complex made up of five identical sub-units.
Which one of the following is CORRECT in relation to activity at the terminal bouton?
a. Voltage-gated Ca++ channels are found only at the active zones.
b. For transmitter release the terminal must be depolarized to produce an action potential.
c. Transmitter molecules are released together with the vesicle into the synaptic cleft.
d. Docking proteins are the sites at which vesicles wait to be filled with transmitter molecules.
e. The active zone causes recycling of vesicles that may have released transmitter molecules.
Which one of the following is CORRECT in relation to activity at the terminal bouton?
a. Voltage-gated Ca++ channels are found only at the active zones.
Terminal Bouton = pre-synaptic terminal
b. Transmitter release is due to the influx of Calcium ions
c. Vesicles are not released with transmitter molecules
d. Docking = process during which the vesicle and pre-synaptic membrane line up in a fusion ready state
e. Only the vesicles at the active site can release transmitter molecules
Which one of the following is CORRECT?
a. Chemical synapses produce slow voltage changes whereas electrical synapses produce slow biochemical changes.
b. Transmission at a chemical synapse depends on release of quanta of non-peptide or peptide transmitter.
c. Electrical synapses only transmit information in one direction.
d. Chemical synapses allow bidirectional flow of information through gap-junction channels.
e. Transmission at a chemical synapse is faster than at an electrical synapse.
Which one of the following is CORRECT?
b. Transmission at a chemical synapse depends on release of quanta of non-peptide or peptide transmitter.
.
Which one of the following is INCORRECT in relation to transmitter release?
a. Calcium entry into the terminal bouton is essential.
b. Depolarisation of the terminal axon is necessary.
c. Each vesicle contains a similar amount (quantum) of transmitter.
d. Only docked vesicles fuse with the pre-synaptic membrane.
e. A decrease in calcium concentration in the terminal enhances transmitter release.
Which one of the following is INCORRECT in relation to transmitter release?
e. A decrease in calcium concentration in the terminal enhances transmitter release.
What features best characterise a prototypical neuron?
a. A resting membrane potential of -65mV
b. The ability to generate an action potential
c. Mechanisms for action potential generation and neurotransmitter release
d. The ability to release neurotransmitter
e. Myelinated axons and unmyelinated dendrites
What features best characterise a prototypical neuron?
d. The ability to release neurotransmitter
What is the role of Oligodendroglia?
a. Produce myelin, which electrically insulates axons
b. Are intimately connected with axons and dendrites to improve synaptic conduction
c. Improve conduction velocities in axons and dendrites
d. Produce myelin, which increases axonal conduction velocity by decreasing membrane resistance
e. Buffer K+ ions to help prevent excitotoxicity
What is the role of Oligodendroglia?
a. Produce myelin, which electrically insulates axons
c. Too vague
d. It increases membrane resistance
e. Astrocytes buffer K+ ions to help prevent excitotoxicity
The dendrites of a neuron are
a. the cytoplasmic extensions of the cell body at which neurons receive most of their inputs.
b. the output functional component of a neuron and the sites where chemicals are released.
c. the regions of a myelinated neuron which are sheathed by Schwann cells.
d. the sites at which a neuron integrates inputs.
e. the structures that give rigidity to the cell body
The dendrites of a neuron are
a. the cytoplasmic extensions of the cell body at which neurons receive most of their inputs.
What type of glial cell affects neuromodulation over long timescales by detecting and responding to neurotransmitters?
a. Oligodendroglia
b. Astrocytes
c. Microglia
d. Schwann cells
e. Ependymal
What type of glial cell affects neuromodulation over long timescales by detecting and responding to neurotransmitters?
b. Astrocytes
Astrocytes regulate chemical content of extracellular space, and support synaptic signalling. They are also essential in the uptake of neurotransmitters from the synaptic cleft
At a chemical synapse:
a. action potentials are produced by chemical vesicles.
b. binding of chemicals to receptors causes the opening of voltage-gated vesicles in the post-synaptic cell.
c. pre-synaptic terminal depolarisation ultimately causes release of chemicals from vesicles.
d. transmission of activity from pre-synaptic to post-synaptic cells occurs through second messengers.
e. second messengers allow the binding of vesicles to the pre-synaptic membrane.
At a chemical synapse:
c. pre-synaptic terminal depolarisation ultimately causes release of chemicals from vesicles.
a. action potentials are produced by the difference in charge across the cell membrane, not chemical vesicles
b. binding of chemicals to receptors causes the opening or closing of voltage-gated vesicles in the post-synaptic cell
d. transmission occurs through the release of chemicals from vesicles, modulated by astrocytes
e. second messengers relays signals received on the surface of receptor cells
The resting membrane potential is primarily set by which membrane-bound proteins?
a. Two-pore potassium channels (K2P)
b. Voltage gated Ca channels (CaV)
c. The Na+/Ca2+ exchanger
d. Voltage-gated sodium channels (NaV)
e. Voltage-gated potassium channels (KV)
The resting membrane potential is primarily set by which membrane-bound proteins?
a. Two-pore potassium channels (K2P)
- generally open
- contribute to K+ leak
- regulate ion flow physically and chemically
- help set up resting potential
Voltage gated Ca channels (CaV)
- only present in synapse
Na+/Ca2+ exchanger
- used to remove Ca from cells
- powered by ATP
- allow actin + myosin to relax
Voltage-gated sodium channels (NaV)
- closed at resting membrane potential
- 3 conformations:
closed: -65mV
open: upon depolarisation, allow Na ions to enter cell for 1ms
inactive: globular protein block passageway until cell is hyperpolarised
Voltage-gated potassium channels (KV)
- opens depending on membrane potential
- have pore loops
If delayed rectifier, voltage-activated K+ channels did not exist, what would happen to the membrane potential?
a. A more pronounced after-hyperpolarization would be evident following an action potential
b. The resting membrane potential would be higher
c. The resting membrane potential would not be reached after an action potential
d. The resting membrane potential would be reached, but more slowly, after an action potential
e. The voltage peak during an action potential would be lower
If delayed rectifier, voltage-activated K+ channels did not exist, what would happen to the membrane potential?
d. The resting membrane potential would be reached, but more slowly, after an action potential
K+ channels are used for depolarising the membrane. Without it, the membrane would not be as depolarised after the action potential.
In an unusual neuron that you have discovered, the ionic equilibrium potential for chloride ions is 30 mV. If synaptic inputs cause chloride ion channels to open in this neuron, what would you expect to happen to the membrane potential?
a. It should move towards 30 mV
b. It should become more negative
c. It should move towards the resting membrane potential
d. It’s impossible to say without knowing the current membrane potential
e. It should become more positive
In an unusual neuron that you have discovered, the ionic equilibrium potential for chloride ions is 30 mV. If synaptic inputs cause chloride ion channels to open in this neuron, what would you expect to happen to the membrane potential?
a. It should move towards 30 mV
Chloride ion channels open, hence allowing the influx of chloride ions, depolarizing the membrane until it reaches 30mV.
In extreme cases, it is possible for the Na+/K+-ATPase pump to run in reverse. The conditions most likely to lead to this unusual scenario are:
a. reduced intracellular [Na+] and increased extracellular [ATP]
b. reduced intracellular [Na+] and reduced intracellular [ATP]
c. increased extracellular [Na+] and increased intracellular [K+]
d. increased intracellular [Na+] and increased intracellular [K+]
e. an extracellular solution completely deficient in K+ ions
In extreme cases, it is possible for the Na+/K+-ATPase pump to run in reverse. The conditions most likely to lead to this unusual scenario are:
a. reduced intracellular [Na+] and increased extracellular [ATP]
Pumping K+ into the cell and Na+ out occurs during depolarisation. Doing the opposite can occur when there is increased extracellular ATP and reduce intracellular Na+. Having increased intracellular Na+ requires the pump to try to pump Na+ in. ATP is required in the pumping process.
When measured at the synapse where they originate, excitatory post-synaptic potentials (EPSPs):
a. Cannot summate, because they are all-or-none processes
b. Are quantized because there is a fixed amount of neurotransmitter in each pre-synaptic vesicle
c. Depend primarily on the movement of Chloride ions
d. Are usually large enough to generate an action potential
e. Have a peak amplitude that depends on the membrane length constant
When measured at the synapse where they originate, excitatory post-synaptic potentials (EPSPs):
b. Are quantized because there is a fixed amount of neurotransmitter in each pre-synaptic vesicle
a. They can summate, as the APs can overlap during depolarisation period
c. EPSPs are due to release of neurotransmitters into post synaptic cleft
d. EPSPs are depolarising, and hence prepare the cell for action potential. Sometimes one isn’t enough to trigger an AP, hence requires summation
e. The peak amplitude is affected by:
- type and number of channels open
- modulating synaptic efficacy
- probability of vesicle release
- inhibition
- EPSPs = excitatory = Na+
- IPSPs = inhibitory = Cl-
Comparing ionotropic and metabotropic receptors, which of the following is true:
a. ionotropic receptors only allow ions to pass through, whereas metabotropic receptors can pass ions and small molecules
b. metabotropic receptors are always ligand-gated, whereas ionotropic can be voltage-gated or ligand-gated
c. the effects of metabotropic receptors are slower and longer lasting than those of ionotropic receptors
d. metabotropic receptors bind metabolites, whereas ionotropic receptors bind or pass ions
e. ionotropic receptors are inhibitory and metabotropic receptors are excitatory
Comparing ionotropic and metabotropic receptors, which of the following is true:
c. the effects of metabotropic receptors are slower and longer lasting than those of ionotropic receptors
Ionotropic
- ion channel is gated by a ligand
- fast and brief
- typically less selective than VGC
Metabotropic
- receptor directly linked with ion channel
- neurotrans binding activates G-protein
- G-protein moves along embrane to activate ion channel/enzyme
In order to demonstrate the quantal release of neurotransmitter, required a synapse in which a limited number of vesicles were simultaneously released from an axon terminal. To do this, it was necessary to study the phenomenon:
a. using an extracellular fluid containing magnesium ions, because magnesium prevents vesicle release
b. using an extracellular fluid effectively no calcium ions, because calcium drives neurotransmitter release
c. in proximal synapses, where post-synaptic potentials are very small
d. by stimulating axons with two closely spaced action potentials, so that most vesicles were released in response to the first action potential
e. at the neuromuscular junction, because synapses at muscles normally only release a small number of neurotransmitter vesicles.
In order to demonstrate the quantal release of neurotransmitter, required a synapse in which a limited number of vesicles were simultaneously released from an axon terminal. To do this, it was necessary to study the phenomenon:
b. using an extracellular fluid effectively no calcium ions, because calcium drives neurotransmitter release
To see whether each vesicle had roughly the same amount of neurotransmitters, it must be ensured that all neurotransmitters are released under the same conditions, hence:
- similar concentration of Ca ions (Ca ions drive neurotrans release)
- released the first time
(no overlap in AP, otherwise second time release more)
Halorhodopsin is a light-gated chloride-ion pump that can be expressed in neurons using viral methods. Application of light with a wavelength of 570 nm causes the pump to move chloride ions into the neuron, regardless of the chemical or electrical gradient across the membrane. If light of 570 nm is shone onto a neuron expressing halorhodopsin:
a. the neuron will be less likely to fire action potentials
b. the neuron will have an increased probability of vesicle release
c. the neuron will be more likely to fire action potentials
d. the neuron will have an decreased probability of vesicle release
e. changes are impossible to predict because they depend on the current membrane potential
Halorhodopsin is a light-gated chloride-ion pump that can be expressed in neurons using viral methods. Application of light with a wavelength of 570 nm causes the pump to move chloride ions into the neuron, regardless of the chemical or electrical gradient across the membrane. If light of 570 nm is shone onto a neuron expressing halorhodopsin:
a. the neuron will be less likely to fire action potentials
More chloride in the cell hyperpolarises the cell. This would make it harder to fire APs.
Vesicle release depends on Ca+ ions and the Na+/Ca2+ pump
At the post-synaptic cell, neurotransmitters produce voltage changes:
a. only by binding to membrane-bound receptors that form ion channels.
b. only by binding to receptors that are protein complexes made up of five sub-units.
c. that are always a depolarization of the post-synaptic resting membrane potential.
d. that may be a depolarization or a hyper-polarization of the post-synaptic resting membrane potential.
e. through receptors that selectively allow the movement of only one ion.
At the post-synaptic cell, neurotransmitters produce voltage changes:
d. that may be a depolarization or a hyper-polarization of the post-synaptic resting membrane potential
Polarity of voltage changes depends on whether it is an EPSP or IPSP (ie, whether neurotransmitters are predominantly Na+ or Ca++), hence either a hyper/depolarisation.
Some receptors allow the movement of more than one ion.
Binding sites on receptors are
a. The regions that make the receptor selective for the type of ion
b. Found only on membrane-bound receptors.
c. The regions where the ligand can bind to elicit a cellular response.
d. Found only on receptors that form as ion channels.
e. The regions where a conformational change allows G proteins to bind to the receptor.
Binding sites on receptors are
c. The regions where the ligand can bind to elicit a cellular response.
This is addressing ionotropic receptors. They do not make the receptor selective for certain types of ions.
G proteins are specifically for metabotropic receptors
You are studying a glutamatergic neuron in the central nervous system, and expect the probability of vesicular release to be low (Pr=0.1). If two action potentials (APs) arrive with a separation of 25 ms at the synapse, what would you predict to observe in association with the second action potential compared to the first:
a. larger post-synaptic depolarisation, because of increased neurotransmitter release
b. greater post-synaptic calcium influx, because more voltage-gated calcium channels open
c. larger post-synaptic calcium influx, because of increased neurotransmitter release
d. smaller post-synaptic depolarisation, because most membrane-bound neurotransmitter would already be released
e. larger pre-synaptic depolarisation, because of increased calcium influx
You are studying a glutamatergic neuron in the central nervous system, and expect the probability of vesicular release to be low (Pr=0.1). If two action potentials (APs) arrive with a separation of 25 ms at the synapse, what would you predict to observe in association with the second action potential compared to the first:
a. larger post-synaptic depolarisation, because of increased neurotransmitter release
probability of neurotransmitter release on the second time = 0.9
Which of the following statements regarding the blood-brain barrier is/are CORRECT? MORE than ONE option may be Correct. Please select ALL Correct options.
a. The blood-brain barrier is made up of endothelial cells, astrocyte foot processes and tight-junctions
b. The blood-brain barrier prevents all macromolecules (including glucose) from entering the brain
c. The blood-brain barrier is a result of tight junctions between endothelial cells and capillaries”
Which of the following statements regarding the blood-brain barrier is/are CORRECT? MORE than ONE option may be Correct. Please select ALL Correct options.
a,c
Endothelial cells produce cerebral spinal fluid
Astrocytes manage the tight junctions
Which of the following statements relating to the meninges and cerebrospinal fluid (CSF) which act to provide a buffer in which the CNS (including the brain and spinal cord) are CORRECT? MORE than ONE option may be Correct.
a. The pia mater is the outermost layer closest to the skull
b. The pia mater is separated from the arachnoid space by a space filled with cerebrospinal fluid
c. CSF is produced by the choroid plexus located within the ventricles
d. The meninges comprise of the pia mater, dura mater and arachnoid mater
Which of the following statements relating to the meninges and cerebrospinal fluid (CSF) which act to provide a buffer in which the CNS (including the brain and spinal cord) are CORRECT? MORE than ONE option may be Correct.
b, c, d
From outer to inner:
dura mater: hardest
arachnoid mater: connecting
pia mater: softest inner