Chapter 8

For cells that communicate by electrical synapses, the message travels between cells via ________. A) ions moving across the synaptic cleft B) the diffusion of neurotransmitters C) gap junctions D) active transport across the synaptic cleft E) passive transport across the synaptic cleft

Which of the following statements about synapses is FALSE? A) Communication across electrical synapses is bi-directional. B) Neurotransmitters can move from one cell to another through gap junctions at an electrical synapse. C) Communication at chemical synapses is slower than at electrical synapses. D) Electrical synapses can be gated. E) Most synapses in the nervous system are chemical synapses.

Which of the following statements about electrical synapses is FALSE? A) Gap junctions are formed from proteins called connexins. B) Electrical synapses connect hypothalamic neurons that release tropic hormones. C) Electrical synapses are found in the retina. D) Electrical synapses are found in the brainstem. E) All electrical synapses provide for bi-directional communication.

The chemical synapse is bounded by the ________ neuron, from which neurotransmitters are released across the synaptic cleft, to the ________ neuron, where the receptors for that neurotransmitter are located. A) presynaptic : postsynaptic B) postsynaptic : presynaptic C) parasynaptic : postsynaptic D) presynaptic : parasynaptic E) terminal : presynaptic

What type of synapse occurs between an axon terminal of one neuron and the axon from another neuron? A) axodendritic synapse B) axoaxonic synapse C) axosomatic synapse D) dendroaxonic synapse E) somatoaxonic synapse

What type of synapse occurs between an axon terminal of one neuron and the cell body of another neuron? A) axodendritic synapse B) axoaxonic synapse C) axosomatic synapse D) dendroaxonic synapse E) somatoaxonic synapse

The neurotransmitter that is released from the presynaptic neuron must diffuse across the ________ to reach the postsynaptic neuron. A) axon hillock B) dendrite C) cell body D) axon E) synaptic cleft

What type of ion channels are necessary for the function of the axon and the axon terminal? A) receptor-gated B) mechanically-gated C) ligand-gated D) voltage-gated E) chemically-gated

Synaptic vesicles store ________. A) calcium B) sodium C) potassium D) neurotransmitter E) enzymes that degrade neurotransmitter

Most neurotransmitters are synthesized in what region of a neuron? A) cytosol B) synaptic vesicles C) Golgi apparatus D) rough endoplasmic reticulum E) axon hillock

Neurotransmitter release occurs by what mechanism? A) diffusion B) primary active transport C) secondary active transport D) endocytosis E) exocytosis

Voltage-gated calcium channels in the axon terminal open in response to which of the following? A) initiation of an action potential in the axon hillock B) arrival of an action potential at the axon terminal C) neurotransmitter binding to receptor D) summation of graded potentials at the axon hillock E) paracrines released from the post-synaptic cell

The influx of calcium into the axon terminal of a chemical synapse is responsible for which of the following? A) initiation of an action potential B) termination of an action potential C) fusion of vesicles to the membrane and of exocytosis neurotransmitter D) diffusion of the neurotransmitter across the membrane and into the cleft E) movement of calcium through gap junctions

Which of the following is NOT a mechanism whereby neurotransmitters are rapidly removed from the synaptic cleft? A) diffusion out of the cleft B) degradation by enzymes C) active reuptake across the presynaptic membrane D) binding to the receptor E) transport back up the axon to be immediately repackaged

Neurotransmitters can be reused through the process of ________, where neurotransmitters are transported across the presynaptic membrane. A) reuptake B) regeneration C) recycling D) resynthesis E) receptor binding

The extent of neurotransmitter binding to receptors on the postsynaptic membrane is determined primarily by which of the following? A) sodium B) calcium C) the distance of the cleft D) the concentration of neurotransmitter E) neurotransmitter vesicles

The synaptic delay is caused by the time required for which step of neurotransmitter release? A) an action potential to move from axon hillock to axon terminal B) the synthesis of neurotransmitter C) packaging of neurotransmitter into synaptic vesicles D) calcium entry to trigger exocytosis E) the neurotransmitter to diffuse across the synaptic cleft

What type of receptor is responsible for the rapid opening of ion channels in response to the interaction between the ligand and receptor? A) mechanotropic receptor B) metabotropic receptor C) ionotropic receptor D) potentiotropic receptor E) chemotropic receptor

The opening of ion channels that is stimulated by the binding of a neurotransmitter to its receptor on a neighboring neuron, and the subsequent movement of ions across that membrane, describes the development of which of the following? A) action potential B) presynaptic potential C) neurogenic potential D) postsynaptic potential E) cleft potential

The rapid change in membrane potential that occurs when a ligand binds to an ionotropic receptor is caused by which of the following? A) the rapid gating of the ion channel by G protein B) the rapid G protein response that indirectly links receptor to channel C) the G protein amplification that causes the rapid channel response D) the presence of one protein that functions as both an ionotropic receptor and an ion channel E) the large ion gradient across the membrane

Synaptic potentials are produced at what type of synapse? A) axo-axonic, axo-dendritic, and axo-somatic synapses B) axo-axonic and axo-dendritic synapses only C) axo-axonic and axo-somatic synapses only D) axo-dendritic and axo-somatic synapses only E) axo-dendritic synapses only

At ionotropic receptors, a(n) ________. A) neurotransmitter binding to a receptor opens channels that are a part of the same protein as the receptor B) neurotransmitter binding to a receptor opens channels that are a separate protein from the receptor C) neurotransmitter binding to a receptor opens or closes channels that are part of the same protein as the receptor D) neurotransmitter binding to a receptor opens or closes channels that are a separate protein from the receptor E) ion binding to a receptor opens channels in the plasma membrane

Presynaptic modulation occurs at what type of synapse? A) axo-dendritic B) axo-axonic C) axo-somatic D) dendro-dendritic E) dendro-somatic

Metabotropic receptor-induced gating of ion channels requires more time to occur because of which of the following? A) their gating is linked to a G protein B) the channels are slower to open C) intracellular calcium must increase before those channels will open D) ion channels linked to metabotropic receptors must move to the membrane before gating E) metabolic byproducts are required to open those channels

What is a change in the postsynaptic potential that brings membrane potential closer to threshold called? A) excitatory postsynaptic potential B) inhibitory postsynaptic potential C) suprathreshold postsynaptic potential D) hyperpolarizing postsynaptic potential E) inhibitory presynaptic potential

The most common mechanism for producing a fast EPSP involves which of the following? A) opening of sodium-selective channels B) opening of potassium-selective channels C) closing of sodium-selective channels D) closing of potassium-selective channels E) opening of channels that permit both sodium and potassium to flow through

What ion directly triggers neurotransmitter release from the presynaptic neuron? A) sodium B) potassium C) chloride D) calcium E) magnesium

An example of a slow excitatory postsynaptic potential that involves closure of potassium channels relies on cAMP produced by what enzyme? A) phosphodiesterase B) protein kinase A C) G protein D) adenylate cyclase E) protein kinase C

The duration of a slow, excitatory postsynaptic potential mediated by cAMP is driven by the extent of time that cAMP remains active before being degraded by what protein? A) phosphodiesterase B) protein kinase A C) G protein D) adenylate cyclase E) protein kinase C

Fast excitatory responses not only occur quickly, but ________. A) they also have a slow component B) they remain active for a long period of time C) they end quickly D) they always create a substantial depolarization E) they are maintained for minutes to hours

The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the ________ of ________ channels. A) opening : chloride B) closure : potassium C) opening : sodium D) closure : chloride E) opening : calcium

The binding of a neurotransmitter to its receptor at an inhibitory synapse can lead to the ________ of ________ channels. A) opening : potassium B) closure : potassium C) opening : sodium D) closing : chloride E) opening : calcium

In the absence of active chloride ion transport, opening of chloride channels in a cell that has hyperpolarized will result in which of the following? A) net movement of chloride out of the cell B) net movement of chloride into the cell C) movement of chloride equally in both directions D) absence of any chloride movement E) depolarization of the cell

In the presence of active chloride ion transport within a neuron, the opening of chloride channels will result in which of the following? A) net movement of chloride out of the cell B) net movement of chloride into the cell C) movement of chloride equally in both directions D) absence of any chloride movement E) depolarization of the cell

If the resting membrane potential is equal to chloride's equilibrium potential, in which direction will chloride ions move if chloride channels open while the cell remains at resting membrane potential? A) inward B) outward C) No ions will move through the channel. D) Ions will move equally in both directions. E) Three chloride ions will move out for every two chloride ions that move in.

In the absence of an active chloride transporter in the plasma membrane, chloride acts to ________ membrane potential by resisting any change in membrane potential. A) hyperpolarize B) depolarize C) stabilize D) modify E) alter

The opening of a chloride channel acts to ________ the development of an action potential at the axon hillock. A) stimulate B) inhibit C) facilitate D) further E) enhance

Convergence in neurophysiology refers to which of the following? A) the presence of EPSPs and IPSPs on a neuron at the same time B) the communication of several neurons to one postsynaptic cell C) the summation of graded potentials to determine whether or not an action potential will be generated D) the level of depolarization required to generate an action potential E) the arrival of an action potential at the axon terminal

The final integration of postsynaptic potentials that determines whether an action potential is generated occurs within what region of a neuron? A) dendrites B) cell body C) axon D) axon hillock E) rough endoplasmic reticulum

The degree of summation that can occur for inhibitory postsynaptic potentials is limited by what? A) the equilibrium potential for sodium B) the extent of depolarization that is occurring at the same time C) the equilibrium potential for potassium D) the equilibrium potential for the ion creating the hyperpolarization E) the equilibrium potential for chloride

For ionotropic receptors, their ________ response ________ the likelihood that two pulses from the same neuron will summate. A) rapid : decreases B) rapid : increases C) rapid : does not affect D) slow : decrease E) slow : increase

Which of the following would increase the likelihood of an action potential being generated in a postsynaptic cell? A) presynaptic inhibition at an excitatory synapse B) presynaptic excitation at an excitatory synapse C) opening of potassium channels on the postsynaptic cell D) opening of chloride channels on a postsynaptic cell with no active transport of chloride ions E) opening of chloride channels on a postsynaptic cell that actively transports chloride ions out of the cell

Which of the following statements about inhibitory synapses is FALSE? A) Opening of potassium channels can generate an IPSP. B) Opening of chloride channels can generate an IPSP. C) In presynaptic inhibition, opening of chloride channels can stabilize the membrane, opposing a depolarizing force. D) The membrane potential of the postsynaptic cell can be hyperpolarized. E) The postsynaptic cell is less likely to generate an action potential.

For the slow receptors, the likelihood of summation is ________ by the ________ of time required for those responses to decay. A) decreased : short period B) increased : short period C) decreased : long period D) increased : long period E) unaffected : long period

As the amplitude of the excitatory postsynaptic potential increases above threshold, the time between each action potential will ________, thereby increasing the ________ of the action potentials. A) decrease : frequency B) decrease : amplitude C) increase : frequency D) increase : amplitude E) not be altered : amplitude

Suprathreshold graded potentials within a neuron can generate ________ action potential(s) at the axon hillock, which allows for the ________ of the magnitude of the stimulus. A) multiple : amplitude coding B) multiple : frequency coding C) a single : frequency coding D) a single : amplitude coding E) several : amplitude coding

Axoaxonic synapses are responsible for ________ the extent of neurotransmitter released at the synapse. A) inhibiting B) decreasing C) increasing D) modulating E) enhancing

Presynaptic modulation of neurotransmitter release involves modifying ________ at the axon terminal. A) membrane potential B) calcium influx C) the vesicles selected for release D) sodium channels E) potassium channels

During presynaptic inhibition, the release of a neurotransmitter from the modulating neuron causes which of the following? A) a decrease in neurotransmitter release from the neuron it is modulating B) a hyperpolarization of the neuron it is modulating C) an IPSP on the postsynaptic cell D) an EPSP on the postsynaptic cell E) an increase in calcium entry into the axon terminal of the neuron it is modulating

Which of the following best describes presynaptic facilitation? A) The modulating neuron causes an EPSP on the postsynaptic cell. B) The modulating neuron enhances neurotransmitter release from the postsynaptic cell. C) The modulating neuron triggers an action potential in the postsynaptic cell. D) The modulating neuron stabilizes the membrane potential of the postsynaptic cell. E) The modulating neuron decreases the effective communication between the cell it is modulating and its postsynaptic cell.

The synthesis of acetylcholine involves an enzyme called ________, which is present within the cytosol and is responsible for converting ________ into acetylcholine. A) choline acetyl transferase : choline + acetate B) acetylcholinesterase : acetyl CoA + choline C) choline acetyl transferase : acetyl CoA + choline D) acetylcholinesterase : choline E) choline acetyl transferase : acetyl CoA

Neurons that synthesize and release acetylcholine are called ________. A) cholinergic neurons B) adrenergic neurons C) dopaminergic neurons D) nitridergic neurons E) acetylergic neurons

Once released, acetylcholine is degraded by extracellular enzymes into what product(s)? A) acetate + choline B) acetyl CoA + choline C) methylcholine + acetate D) choline only E) acetate only

What is transported back into the axon terminal of cholinergic neurons to be resynthesized into active neurotransmitter? A) Acetylcholine B) Acetyl CoA C) Acetate D) Choline E) Epinephrine

What type of receptor is both ionotropic and cholinergic? A) muscarinic receptors B) dopaminergic receptors C) nitridergic receptors D) adrenergic receptors E) nicotinic receptors

What type of receptor is both metabotropic and cholinergic? A) muscarinic receptors B) dopaminergic receptors C) nitridergic receptors D) adrenergic receptors E) nicotinic receptors

Which of the following is a neurotransmitter that contains a six-carbon ring with two hydroxyl groups and an amine group? A) acetylcholine B) norepinephrine C) amino acids D) neuroactive peptides E) nitric oxide

Which of the following couplings between neurotransmitter and neurotransmitter class is INCORRECT? A) adenosine : amino acid B) norepinephrine : catecholamine C) histamine : biogenic amine D) enkephalin : neuropeptide E) nitric oxide : gas

Which of the following is an ionotropic purinergic receptor that binds ATP? A) P2X B) P2Y C) A1 D) A2 E) A3

Biogenic amines are synthesized in what region of a neuron? A) cytosol of the cell body B) axon hillock C) rough endoplasmic reticulum D) extracellular space E) cytosol of the axon terminal

The action of adrenergic receptors identifies them as ________ receptors. A) metabotropic B) chemotropic C) ionotropic D) voltage-gated E) mechanically-gated

Which of the following is a biogenic amine that is NOT classified as a catecholamine? A) norepinephrine B) epinephrine C) adrenaline D) serotonin E) dopamine

What two enzymes catalyze the breakdown of catecholamines? A) catechol-O-methyltransferase and acetylcholinesterase B) acetylcholinesterase and dopa decarboxylase C) monoamine oxidase and phenylethanolamine N methyltransferase D) dopa decarboxylase and phenylethanolamine N methyltransferase E) monoamine oxidase and catechol-O-methyltransferase

Epinephrine binds best to which of the following receptor types? A) nicotinic cholinergic receptors B) muscarinic cholinergic receptors C) alpha adrenergic receptors D) beta1 adrenergic receptors E) beta2 adrenergic receptors

Fast EPSPs are produced at which of the following types of receptor? A) nicotinic cholinergic only B) alpha-adrenergic only C) AMPA receptors only D) both nicotinic cholinergic and AMPA receptors E) both nicotinic cholinergic and alpha-adrenergic receptors

In which region of the brain does histamine function as a neurotransmitter? A) hypothalamus B) medulla C) pons D) cerebrum E) cerebellum

) ________ is an amino acid neurotransmitter at excitatory synapses whereas ________ is an amino acid neurotransmitter at inhibitory synapses. A) Gamma-aminobutyric acid : glutamate B) Gamma-aminobutyric acid : glycine C) Glycine : aspartate D) Aspartate : glycine E) Glutamate : aspartate

Which of the following GABA receptor types is coupled to chloride channels? A) GABAA only B) GABAB only C) GABAC only D) both GABAA and GABAB E) both GABAA and GABAC

IPSPs are produced when GABA binds to what class of receptor? A) GABAA only B) GABAB only C) GABAC only D) both GABAA and GABAB E) both GABAA and GABAC

What is the most common inhibitory neurotransmitter in the central nervous system? A) glycine B) GABA C) glutamate D) acetylcholine E) aspartate

Neuropeptides are synthesized in what region of a neuron? A) within the axon terminal B) in the rough endoplasmic reticulum C) along the axon D) within the vesicles E) at the dendrite

Which of the following compounds is NOT a neuropeptide? A) substance P B) vasopressin C) oxytocin D) endorphin E) epinephrine

Which of the following is a hypothalamic neuropeptide that regulates the sleep-wake cycle? A) orexin B) vasopressin C) oxytocin D) melatonin E) substance P

Nitric oxide is a ________ that functions as a neurotransmitter. A) catecholamine B) gas C) neuroactive peptide D) biogenic amine E) amino acid

Which of the following chemicals is NOT a known neurotransmitter? A) acetylcholine B) nitric oxide C) ATP D) substance P E) carbon dioxide

What chemical targets CB1 receptors? A) tetrahydrocannabinol B) enkephalin C) carbonic acid D) carbon dioxide E) glutamate