Lecture 7: Neurons and Synapses [Ninety-two entries]
#80) An axon will depolarize only if the membrane potential reaches between -70mV and -55mV. This follows the ________. - all-or-none law - recruitment law - graduated law - threshold law
all-or-none law
#72) The most numerous of all cells of CNS nervous tissue are the________. - astrocytes - neurons - Schwann cells - satellite cells
astrocytes
#71) The synapses which occur between axons of presynaptic cells and dendrites of postsynaptic cells are called ________. - axodendritic - axosomatic - myoneural - axoaxonic
axodendritic
#35) Enhancing the excitability of a synapse so that transmission is favored along certain pathways is called________. - long-term potentiation - synaptic plasticity - excitotoxicity - summation
long-term potentiation
#42) GABA causes IPSPs by - opening K+ channels - opening Na+ channels - opening Cl- channels
opening Cl- channels
#82) What causes the repolarization phase of the action potential? - potassium influx - potassium efflux - sodium influx - sodium efflux
potassium efflux
#83) What causes the hyperpolarization phase of the action potential? - potassium efflux - potassium influx - sodium influx - sodium efflux
potassium efflux
#77) The membrane of resting nerve cells is more permeable to ________ ions than ________ ions. - sodium, potassium - calcium, potassium - potassium, sodium - chloride, potassium
potassium, sodium
#54) Neurotransmitters ________. - Are released by endocytosis - Bind to voltage-gated channels - Bind to chemically gated channels - Are actively transported across the synaptic cleft
Bind to chemically gated channels
#6) Synaptic transmission using acetylcholine would be disrupted by ________. - Curare - Botulinum toxin - Strychnine - Both curare and botulinum toxin are correct.
Both curare and botulinum toxin are correct
#16) Hyperpolarization in the postsynaptic cell is caused by _______. - Excitatory postsynaptic potentials - Inhibitory postsynaptic potentials - Movement of K+ out of the cell - Both inhibitory postsynaptic potentials and movement of K+ out of the cell are correct.
Both inhibitory postsynaptic potentials and movement of K+ out of the cell are correct.
#60) The nucleus is housed in the: - Cell body - Dendrite - Axon terminal - Nissl bodies
Cell body
#14) The blood-brain barrier prevents hydrophobic molecules from diffusing into the brain. - True - False
False
#17) Somatic motor neurons innervate involuntary effectors. - True - False
False
#22) Nicotinic receptors utilize G-proteins to regulate the opening of ion channels - True - False
False
#65) During the absolute refractory period, a supramaximal stimulus can bring the cell to threshold. - True - False
False
#51) The most common inhibitory neurotransmitter in the brain is________. - Glycine - Acetylcholine - Serotonin - GABA
GABA
#88) Benzodiazepines act by increasing ________ activity. - GABA - glutamate - ACh - enkephalin
GABA
#55) In the CNS, which neuroglial cells have an immune function? - Microglia - Astrocytes - Ependymal cells - Schwann cells
Microglia
#87) Which type of cell of the CNS is phagocytic? - Microglia - Satellite cells - Ependymal cells - Oligodendrocytes
Microglia
#44) Structural classifications of neurons do NOT include ________. - Motor neurons - Bipolar neurons - Multipolar neurons - Pseudounipolar neurons
Motor neurons
#49) Most neurons are: - Bipolar - Multipolar - Pseudounipolar
Multipolar
#70) A drug that blocked ________ channels would prevent neurons ________. K +; depolarization Na +; hyperpolarization Na +; depolarization Ca 2+; repolarization
Na +; depolarization
#19) Since sensory neurons for muscle position are the fastest conducting neurons, they would have a larger diameter than slower conducting neurons. - True - False
True
#3) CCK (cholecystokinin) may act as a neurotransmitter in the brain to promote feelings of satiety. - True - False
True
#31) Norepinephrine binding to an adrenergic receptor stimulates the activity of a second messenger system. - True - False
True
#40) Both depolarization and repolarization are produced by the diffusion of ions down their concentration gradient. - True - False
True
#8) Serotonin is synthesized from the amino acid________. - Alanine - Glycine - Tryptophan - Serine
Tryptophan
#32) All of the following are considered monoamines, EXCEPT: - serotonin - dopamine - histamine - acetylcholine
acetylcholine
#30) Histamine is able to ________. - act as a neurotransmitter to cause skeletal muscle contraction - act as a hormone that inhibits gastric secretion - act as a neurotransmitter in the brain to cause drowsiness - act as a regulator in inflammation and allergies
act as a regulator in inflammation and allergies
#81) Sensory neurons are: - afferent - efferent - association
afferent
#23) If a cell's membrane is not excitable, this means that ________. - The cell is a neuron - The cell cannot vary the permeability of the membrane to specific ions - The cell does not have a measurable voltage
The cell cannot vary the permeability of the membrane to specific ions
#10) What do muscarine and nicotine have in common? - They are both antagonists for their respective receptors. - They are both agonists for their respective receptors. - They both activate-protein coupled channels. - They are both always excitatory.
They are both agonists for their respective receptors.
#21) Choose the incorrect statement regarding EPSPs. - They are graded responses. - They are capable of summation. - They have a refractory period. - They are initiated by neurotransmitters.
They have a refractory period.
#66) The minimum depolarization needed to open Na+ gates is called the________. - Repolarization - Threshold - Refractory period - All-or-none law
Threshold
#5) Cholinergic fibers use ________as the neurotransmitter. - Norepinephrine - Acetylcholine - Dopamine - Serotonin
Acetylcholine
#63) The neurotransmitter found at the neuromuscular junction of skeletal muscle is: - Acetylcholine - Glutamate - Serotonin - Serotonin - GABA
Acetylcholine
#53) How is stimulus intensity encoded? - Action potential amplitude - Action potential frequency
Action potential frequency
#15) If a postsynaptic neuron binds to a neurotransmitter that open sodium ion channels: - An EPSP would result - An IPSP would result
An EPSP would result
#62) Sensory neurons_______. - Are multipolar, and carry impulses toward the CNS - Are pseudounipolar, and carry impulses toward the CNS - Are bipolar, and carry impulses away from the CNS - Are multipolar, and carry impulses away from the CNS
Are pseudounipolar, and carry impulses toward the CNS
#50) The blood-brain barrier results mostly from the action of ________, a type of neuroglia. - Ependymal cells - Microglia - Astrocytes - Oligodendrocytes
Astrocytes
#61) Which division of the nervous system innervates involuntary effectors? - Central nervous system - Somatic nervous system - Autonomic nervous system - Associative nervous system
Autonomic nervous system
#24) The period of time when Na + channels are recovering from their inactive state and K + channels are still open is the________. - repolarization - absolute refractory period - relative refractory period - Both repolarization and relative refractory period are correct.
Both repolarization and relative refractory period are correct.
#58) Which of the following is NOT a function of neuroglia? - Bind neurons together - Help nourish neurons - Conduct impulses to effectors - Modify the extracellular environment of the neurons
Conduct impulses to effectors
#59) When the membrane potential become less negative, the neuron is exhibiting - Depolarization - Hyperpolarization - Repolarization
Depolarization
#1) If a neurotransmitter closes potassium ion channels that were previously open, you would get an: - EPSP - IPSP
EPSP
#75) If a neurotransmitter closes chloride ion channels that were previously open, you would get an: - EPSP - IPSP
EPSP
#37) Excitatory postsynaptic potentials are produced in the brain primarily by ________. - Glycine - Glutamic acid - Gamma-aminobutyric acid - Benzodiazepines
Glutamic acid
#28) Which of the following statements about myelination is FALSE? - White matter is composed of myelinated axons - Gray matter is composed of myelinated axons - The spaces of the axon between adjacent glial cells are called the nodes of Ranvier - The purpose of myelination is to speed up the propagation of the action potential
Gray matter is composed of myelinated axons
#20) Which of the following is NOT classified as a catecholamine - Norepinephrine - Epinephrine - Histamine - Dopamine
Histamine
#43) If a neurotransmitter closes sodium ion channels that were previously open, you would get an: - EPSP - IPSP
IPSP
#36) How do neurons code for a greater response? - Greater amplitude of stimuli - Greater Na+ concentration gradient - Increased frequency of stimuli - More active Na+/K+ pump
Increased frequency of stimuli
#68) What is NOT true of conduction through dendrites and cell bodies of neurons? - It creates EPSPs. - It is spread by cable properties. - EPSPs can summate to reach a threshold. - It generates action potentials in the cell body.
It generates action potentials in the cell body.
#7) Nicotinic acetylcholine receptors are: - Ligand-gated channels - Metabotropic
Ligand-gated channels
#84) Serotonin is broken down by: - AchE - MAO - COMT
MAO
#18) The ________ dopamine system may be involved in emotional reward and drug addiction - Nigrostriatal - Mesolimbic - Amygdala - Dentate
Mesolimbic
#48) Muscarinic acetylcholine receptors are: - Ligand-gated - Metabotropic
Metabotropic
#45) Since the action potential "leaps" from node to node in a myelinated axon, ________. - myelinated axons need far less Na + channels than unmyelinated axons - action potentials move faster if the nodes are farther apart - Na+ movement within the myelin sheath is possible - Na+ channels are not present between the nodes
Na+ channels are not present between the nodes
#86) What is needed to return a membrane to its resting membrane potential, with all ions in the correct locations? - Influx of negatively charged ions into the cell - Outflow of Na+ ions via passive ion channels - Na+/K+ pump action - Outflow of K+ ions via passive ion channels
Na+/K+ pump action
#64) The most abundant neuropeptide in the brain is ________. - Neuropeptide Y - Neuropeptide Z - Substance P - CCK
Neuropeptide Y
#38) Chemicals that stimulate action potentials in postsynaptic cells are called________. - Hormones - Enzymes - Neurotransmitters - Neurotrophins
Neurotransmitters
#39) Curare is a competitive ACh antagonist at ________ ACh receptors. - Muscarinic - NMDA - Kainate - Nicotinic
Nicotinic
#67) Which of the following is a catecholamine? - Norepinephrine - Acetylcholine - Nitric oxide - All of the choices are correct
Norepinephrine
#9) Ach bound to nAchR causes EPSPs by: - Opening K+ channels - Opening Na+ channels - Opening Cl- channels
Opening Na+ channels
#91) What action would produce an IPSP on the postsynaptic membrane? - Influx of Na+ ions - Opening of Ca 2+ channels into the neuron - Outflow of K+ ions - Closing of Cl - channels into the neuron
Outflow of K+ ions
#46) What type of autonomic fibers release ACh at effectors? - Parasympathetic - Sympathetic - Somatic - Sensory
Parasympathetic
#56) Action potential conduction in a myelinated axon is called: - Continuous conduction - Saltatory conduction
Saltatory conduction
#57) Conduction of an action potential in a myelinated axon is called________. - Point to point conduction - Saltatory conduction - Refractory conduction - Cable conduction
Saltatory conduction
#11) Muscarinic Ach receptors are found in all of the following locations EXCEPT ________. - Skeletal muscle - Smooth muscle - Cardiac muscle - Glands
Skeletal muscle
#41) What is the predominant effect of stimulation of nicotinic-gated channels? - Stimulation due to outflow of K+ ions - Inhibition due to outflow of K+ ions - Stimulation due to influx of Na+ ions - Inhibition due to influx of Cl- ions
Stimulation due to influx of Na+ ions
#73) Neurotransmitter release would be inhibited by________. - stimulating repolarization of the axon terminal - blocking Ca 2+ influx in the axon terminal - blocking repolarization of the axon terminal - stimulating protein kinase activity
blocking Ca 2+ influx in the axon terminal
#90) Astrocytes are NOT involved in ________. - uptake of NT from a synapse - stimulation or inhibition neurons - formation of synapses in the CNS - breakdown and engulfment of foreign material in the CNS - formation the blood-brain barrier
breakdown and engulfment of foreign material in the CNS
#25) Action potential propagation in an unmyelinated axon is called: - continuous conduction - saltatory conduction
continuous conduction
#78) Damage to the ________ of a neuron would interfere with its ability to receive sensory input from its surrounding environment. - dendrites - axons - cell body - axon terminals
dendrites
#76) A patient is prescribed an MAO inhibitor by their doctor. Knowing the actions of MAO inhibitors, this patient's diagnosis may be ________. - hypertension, since MAO inhibitors block the release of norepinephrine from sympathetic axons - hypertension, since MAO inhibitors block the degradation of norepinephrine at the synapse - depression, since MAO inhibitors block the binding of serotonin to postsynaptic cells - depression, since MAO inhibitors block the degradation of serotonin at the synapse
depression, since MAO inhibitors block the degradation of serotonin at the synapse
#13) The brain produces lipid neurotransmitters called________. - endocannabinoids - endorphins - enkephalins - nitric oxide
endocannabinoids
#85) The relative refractory period is the time: - it takes the neurotransmitter to diffuse across a synaptic cleft - it takes to reach threshold via temporal summation - following an action potential during which a second action potential cannot be initiated regardless of stimulus strength - following an action potential during which a second action potential can only be initiated by a very strong stimulus
following an action potential during which a second action potential can only be initiated by a very strong stimulus
#47) The absolute refractory period is the time: - it takes a neurotransmitter to diffuse across a synaptic cleft - it takes to reach threshold via temporal summation - following an action potential during which a second action potential cannot be initiated, regardless of stimulus strength - following an action potential during which a second action potential can only be initiated by a very strong stimulus
following an action potential during which a second action potential cannot be initiated, regardless of stimulus strength
#26) The major excitatory neurotransmitter of the CNS is: - acetylcholine - glutamate - serotonin - GABA
glutamate
#69) During the repolarization phase of an action potential, sodium ion channels are - closed - inactivated - open
inactivated
#29) Inhibition of neuropeptide Y synthesis would________. - induce euphoria - induce obesity - stimulate leptin secretion - inhibit eating
inhibit eating
#33) Temporal summation________. - occurs when a single neuron releases neurotransmitter rapidly - occurs because of the convergence of many neurons on a single postsynaptic cell - only involves excitatory postsynaptic potentials - only involves inhibitory postsynaptic potentials
occurs when a single neuron releases neurotransmitter rapidly
#12) Endocannabinoids are retrograde neurotransmitters, meaning they are________. - released from presynaptic neurons and diffuse to the postsynaptic neuron - released from postsynaptic neurons and diffuse to the presynaptic neuron - released from presynaptic neurons and diffuse back to the presynaptic cell body - None of the choices are correct.
released from postsynaptic neurons and diffuse to the presynaptic neuron
#27) The myelinating cells of the PNS are: - oligodendrocytes - astrocytes - satellite cells - schwann cells
schwann cells
#74) During relative refraction - sodium ion channels are all open - sodium ion channels are all inactivated - sodium ion channels are all closed - some sodium ion channels are closed, while some are inactivated
some sodium ion channels are closed, while some are inactivated
#2) Which of the following statements about myelination is TRUE? - white matter is composed of unmyelinated axons - gray matter is composed of myelinated axons - the spaces of the axon between adjacent glial cells are called nodes of Ranvier - the purpose of myelination is to slow down the propagation of the action potential
the spaces of the axon between adjacent glial cells are called nodes of Ranvier
#79) Both excitatory and inhibitory postsynaptic potentials undergo summation. - true - false
true
#89) Parkinson disease is associated with the loss of dopaminergic neurons. - true - false
true
#92) An inhibitory postsynaptic potential could be produced by a neurotransmitter that opens Cl - channels. - true - false
true
#4) Ion channels that open in response to depolarization are called________. - ion-gated channels - voltage-gated channels - stimulation-gated channels - potential-gated channels
voltage-gated channels
#34) The average resting membrane potential of an axon is________. −70mV −85mV 0 mV +30mV
−70mV
