Deck 3: Synapses and Synaptic Transmission

Question 1

When an action potential arrives at the presynaptic terminal:

A)Voltage-gated calcium channels are activated.
B)Intracellular calcium stores are released.
C)Synaptic vesicles fuse to the membrane of the soma.
D)Calcium is actively transported out of the neuron terminal.
E)A,B,and D

Answer 1

B
Explanation: Arrival of an action potential at the presynaptic terminal triggers the opening of voltage-gated calcium channels.This results in an influx of calcium into the neuron terminal and triggers the movement of synaptic vesicles toward release sites.The synaptic vesicles fuse with the presynaptic membrane and release neurotransmitters into the synaptic cleft.

Question 2

ACh receptor subtypes include:

A)Adrenergic and noradrenergic
B)Nicotinic and muscarinic
C)Alpha and beta
D)Alpha and gamma
E)None of the above

Answer 2

B
Explanation: Receptors that bind ACh fall into two categories: nicotinic and muscarinic.These receptors are distinguished by their ability to bind certain drugs.Nicotine,derived from tobacco,selectively activates the nicotinic receptors.Muscarine,a poison derived from mushrooms,activates only the muscarinic receptors.

Question 3

Receptor activity is regulated by:

A)Decreasing the number of receptors through internalization.
B)Decreasing the number of available receptors through inactivation.
C)Increasing the number of active receptors.
D)Both A and B
E)All of the above

Answer 3

E
Explanation: Cells can regulate receptor activity by decreasing the number of receptors through internalization,decreasing the number of functional receptors through inactivation,or increasing the number of active receptors in response to low neurotransmitter levels or infrequent receptor activation.

Question 4

Which of the following neurotransmitters and modulators are implicated in pain perception?

A)Opioid peptides
B)Substance P
C)Dopamine
D)Both A and B
E)All of the above

Question 5

Which one of the following is the first step in the sequence of actions in the G-protein receptor activity cycle?

A)α chain activates a target protein.
B)Neurotransmitter binds with receptor.
C)Membrane channels open,or intracellular target proteins are activated.
D)Receptor protein changes shape.

Question 6

The second messenger in a second messenger system is a(n):

A)G-protein
B)α chain of the G-protein
C)Enzyme inside the neuron that can trigger responses within the neuron
D)Neurotransmitter
E)Gene

Question 7

Neurotransmitters that act ________ are classified as ________,whereas neurotransmitters that act ________are classified as ________.

A)Directly;slow-acting;indirectly;fast-acting
B)Directly;inhibitory;indirectly;excitatory
C)Directly;fast-acting;indirectly;slow-acting
D)Directly;excitatory;indirectly;inhibitory

Question 8

Which of the following is associated with post-traumatic stress disorder?

A)Elevated serotonin levels
B)Reduced dopamine reuptake
C)Hyperactivity of the norepinephrine system
D)All of the above

Question 9

Myasthenia gravis:

A)Is caused by the destruction of gamma-aminobutyric acid (GABA)receptors on the postsynaptic membrane of muscles.
B)Results in the decreased release of ACh at the neuromuscular junction.
C)Is an autoimmune disease that destroys ACh receptors on the postsynaptic membrane of muscles,thus interferes with ACh binding for repetitive muscle contractions.
D)Is successfully treated with removal of the pituitary gland.
E)All of the above

Question 10

An antagonist drug acts by:

A)Preventing the release of a neurotransmitter.
B)Binding to a receptor to facilitate the effect of a neurotransmitter.
C)Elevating neurotransmitter levels in the synaptic cleft.
D)Increasing the number of active receptors on a cell membrane.

Question 11

Which one of the following can serve as the postsynaptic cell of a synapse?

A)Smooth muscle cell in an artery
B)Hepatocyte in the liver
C)Neuron in the thalamus
D)Muscle cell in the triceps
E)All of the above

Question 12

The binding of ACh at the neuromuscular junction results in:

A)An inhibitory postsynaptic potential.
B)Presynaptic facilitation.
C)Presynaptic inhibition.
D)An excitatory postsynaptic potential.

Question 13

How does onabotulinumtoxinA (BOTOX)therapeutically produce paresis in overactive muscles?

A)Acts as an antagonist by binding to the ACh receptor on the postsynaptic membrane.
B)Rapidly degrades ACh in the synaptic cleft.
C)Facilitates the reuptake and sequestration of ACh into the presynaptic cell.
D)Disrupts the protein structure of the muscle cell receptor,thus preventing ACh from binding.
E)Inhibits the release of ACh from the presynaptic terminal at the neuromuscular junction.

Question 14

Which of the following is a type of synaptic connection between neurons?

A)Axosomatic
B)Axoaxonic
C)Axodendritic
D)All of the above

Question 15

Receptor tyrosine kinases:

A)Act through second messenger systems.
B)Are usually activated by neuropeptides or hormones.
C)Function through phosphorylation of tyrosine.
D)Both A and C
E)All of the above

Question 16

N-methyl-D-aspartate (NMDA)receptors:

A)Are involved in long-term potentiation.
B)Bind glutamate.
C)Have been implicated in pathologic changes in the nervous system.
D)A,B,and C
E)None of the above

Question 17

Second messengers may initiate the:

A)Opening of membrane ion channels
B)Activation of genes,causing increased synthesis of specific cellular products
C)Modulation of Ca⁺² levels inside the cell
D)A,B,and C
E)None of the above

Question 18

Substance P is an example of a(n):

A)Amino acid transmitter.
B)Amine transmitter.
C)Peptide transmitter.
D)Histamine transmitter.

Question 19

Which of the following neurotransmitters is paired with its correct description?

A)Glutamate;excitatory transmitter,is important in learning and development.
B)Dopamine;inhibitory transmitter,increases attention to sensory information.
C)GABA;excitatory transmitter,modulates neural activity in the CNS.
D)Acetylcholine;excitatory transmitter,affects mood,arousal,and pain perception.
E)Both A and C

Question 20

Which one of the following is used to treat myasthenia gravis?

A)Medications that inhibit the breakdown of acetylcholine
B)Medications that activate the immune system
C)Removal of the pancreas,which contributes to receptor damage
D)Frequent blood transfusions to prevent anemia
E)All of the above