Deck 3: Chemical Signaling by Neurotransmitters and Hormones

Question 1

Otto Loewi's experiment with frog hearts was important because it demonstrated that

A) the idea of chemical neurotransmission is correct.
B) electrical impulses are responsible for neural transmission.
C) the frog heart can be kept alive when removed from the frog.
D) the neuron doctrine is correct.

Answer 1

A

Question 2

Though he could not see it, Sir Charles Sherrington correctly surmised that neurons do not actually touch one another. This idea has been verified with the use of

A) the electron microscope.
B) the light microscope.
C) frog heart experiments first done by Loewi.
D) electrophysiological recordings.

Answer 2

A

Question 3

The saclike structures in the presynaptic terminal are called _______ and are filled with _______.

A) mitochondria; neurotransmitter molecules
B) synaptic vesicles; mitochondria
C) synaptic vesicles; neurotransmitter molecules
D) mitochondria; ATP

Answer 3

C

Question 4

The most common type of synapse in the brain is the _______ synapse.

A) axoaxonic
B) axodendritic
C) axosomatic
D) presynaptic inhibition

Question 5

Which of the following is not one of the criteria a substance must meet to be considered a neurotransmitter?

A) The presynaptic cell should contain the proposed substance and have a mechanism for synthesizing it.
B) Vesicles containing the substance move down the axon with the action potentials when the neuron is stimulated.
C) Receptors for the proposed substance should be present on the postsynaptic cell.
D) There is a means for inactivating the substance with an antagonist drug.

Question 6

If a substance is a neurotransmitter, stimulation of the presynaptic cell should have the same effect as

A) direct application of the proposed substance to the postsynaptic cell.
B) stimulation of the postsynaptic cell.
C) blocking receptors on the postsynaptic cell.
D) inactivating the substance.

Question 7

The classical neurotransmitters do not include

A) acetylcholine.
B) amino acids.
C) neuropeptides.
D) monoamines.

Question 8

If one neuron contains both a neuropeptide and a classical neurotransmitter,

A) all vesicles in the neuron will contain both substances.
B) stimulation of the neuron will result in release of only one of these.
C) some vesicles will contain only the neuropeptide and other vesicles will contain both substances.
D) some vesicles will contain only the classical neurotransmitter and other vesicles will contain both substances.

Question 9

Which statement about neuropeptides is false?

A) Neuropeptide replenishment after neural activity occurs more slowly than replenishment of classical neurotransmitters.
B) Neuropeptides are only synthesized in the cell body.
C) Necessary enzymes are packed into the vesicle with the protein precursor.
D) Transport of the vesicles down the axon depends on action potential propagation.

Question 10

Which statement about synapses is true?

A) Synapses are uniform in size, transmitter release, and probability of action potential during an action potential.
B) Synapses vary widely in size, transmitter release, and probability of action potential during an action potential.
C) The most prevalent synapses in the brain are axoaxonic synapses.
D) In the rodent hippocampal synapses, a large amount of neurotransmitter is released when neurons fire.

Question 11

Cocaine increases the amount of DA, 5-HT, and NE in the synaptic cleft by

A) preventing metabolism.
B) blocking transporters.
C) blocking autoreceptors.
D) increasing synthesis.

Question 12

Activity at an axoaxonic synapse can directly increase the amount of neurotransmitter released from the postsynaptic cell. This is known as

A) presynaptic inhibition.
B) neuromodulation.
C) axosomatic activation.
D) presynaptic facilitation.

Question 13

The direct effect of depolarization of the presynaptic nerve terminal by the action potential is the

A) docking of vesicles at the active zones.
B) opening of voltage-gated Ca²⁺ channels.
C) packaging of neurotransmitter into vesicles.
D) activation of autoreceptors.

Question 14

The process of releasing neurotransmitter molecules from the vesicles is known as _______ and occurs as a result of an influx of _______.

A) exocytosis; Ca²⁺
B) endocytosis; Ca²⁺
C) exocytosis; Na⁺
D) docking; K⁺

Question 15

Prior to neurotransmitter release, vesicles are transported to specialized regions of the presynaptic terminal called _______ zones, where they bind to the terminal in a process known as _______.

A) priming; docking
B) active; docking
C) active; endocytosis
D) priming; exocytosis

Question 16

Which statement about vesicular recycling is false?

A) It occurs through a process known as endocytosis.
B) Without it, the neuron would grow progressively larger as vesicular membrane is added to the terminal.
C) New vesicles for classical neurotransmitters are reformed and filled in the terminal.
D) The processes of endocytosis and exocytosis constitute vesicle recycling.

Question 17

When activated, somatodendritic autoreceptors

A) increase neurotransmitter release.
B) increase the rate of cell firing.
C) slow the rate of cell firing.
D) reduce neurotransmitter release.

Question 18

Selective blockade of terminal autoreceptors for DA would lead to a(n)

A) increase in neurotransmitter release.
B) decrease in neurotransmitter release.
C) decrease in cell firing.
D) increase in cell firing.

Question 19

Inactivation of neurotransmitters cannot be accomplished by

A) enzymatic breakdown in the synaptic cleft.
B) transport back into the presynaptic cell.
C) transport into the postsynaptic cell.
D) transport into nearby glial cells.

Question 20

What is the significance of the recent findings of the relationship between the human microbiome and the nervous system?

A) Some neurotransmitters are synthesized by gut bacteria, and drugs can alter the gut bacteria populations, thereby influencing our health.
B) Gut bacteria species and diversity can have effects on the nervous system that are similar to drug effects.
C) Chronic stress can lead to higher populations of gut bacteria, thereby affecting health.
D) The nervous system responds to gut bacterial populations and helps to regulate their levels.

Question 21

In contrast to the classical neurotransmitters and the neuropeptides, nitric oxide does not "behave" like a typical neurotransmitter. Which statement regarding nitric oxide signaling is false?

A) It diffuses out of the nerve cell through the cell membrane.
B) It is not released from synaptic vesicles via exocytosis.
C) It may be released from the postsynaptic cell.
D) It may be released from the presynaptic cell.

Question 22

Which statement about ionotropic receptors is true?

A) They rapidly cause intracellular effects.
B) G proteins are activated upon binding of neurotransmitter.
C) They are composed of only one subunit.
D) Binding of an agonist induces long-lasting responses in the cell.

Question 23

Ionotropic receptors may let in _______, which can then act as a(n) _______.

A) Na⁺; second messenger
B) Ca²⁺; kinase
C) Ca²⁺; second messenger
D) Cl^-; effector enzyme

Question 24

Ligand-gated ion channels are _______; G protein-coupled receptors are _______.

A) slow/ionotropic; fast/metabotropic
B) fast/ionotropic; slow/metabotropic
C) slow/metabotropic; fast/ionotropic
D) fast/metabotropic; slow/ionotropic

Question 25

Which statement about metabotropic receptors is false?

A) The receptor itself is an ion channel that opens upon ligand binding.
B) The receptor has one subunit with seven transmembrane domains.
C) They are coupled to intracellular G proteins.
D) When activated they can stimulate effector enzymes.

Question 26

Synaptic inhibition may be produced by ACh acting through metabotropic receptors. This inhibition results from the activation of _______ channels by the G protein.

A) Na⁺
B) Cl^-
C) K⁺
D) Ca²⁺

Question 27

Activating a metabotropic receptor does not result in

A) opening of a G protein-gated ion channel.
B) changes in the levels of a second messenger.
C) fast excitatory transmission.
D) changes in gene expression.

Question 28

Which of the following best represents the sequence of steps following the activation of a metabotropic receptor?

A) Activation of G protein $\rightarrow$ change in activity of effector enzyme $\rightarrow$ activation of protein kinase $\rightarrow$ change in second messenger levels
B) Activation of G protein $\rightarrow$ change in second messenger levels $\rightarrow$ change in activity of effector enzyme $\rightarrow$ activation of protein kinase
C) Change in second messenger levels $\rightarrow$ change in activity of effector enzyme $\rightarrow$ activation of protein kinase $\rightarrow$ activation of G protein
D) Activation of G protein $\rightarrow$ change in activity of effector enzyme $\rightarrow$ change in second messenger levels $\rightarrow$ activation of protein kinase

Question 29

The primary treatment for Parkinson's disease is the administration of the drug L-DOPA, which

A) stimulates the release of dopamine.
B) inhibits the synthesis of dopamine.
C) directly stimulates postsynaptic dopamine receptors.
D) is the synthetic precursor to dopamine (DA).

Question 30

Why would drugs that are allosteric modulators be preferable to agonists or antagonist drugs in the treatment of psychiatric disorders, such as schizophrenia?

A) Allosteric modulators often have fewer side effects because they show greater receptor subtype selectivity.
B) Allosteric modulators have reduced receptor subtype selectivity, so they treat a wider range of disorders.
C) Allosteric modulators are readily available; agonists and antagonists are more difficult to synthesize.
D) Allosteric modulators consistently lead to release of more transmitter, thereby more effectively treating a disorder.

Question 31

_______ receptors mediate the effects of neurotrophic factors.

A) Calcium/calmodulin kinase
B) Tyrosine kinase
C) Protein kinase A
D) Protein kinase C

Question 32

The relaxing effects of _______ on smooth muscle and the resulting dilation of the arteries are due to an increase in the second messenger _______.

A) protein kinase G; cGMP
B) protein kinase A; cAMP
C) nitric oxide; cGMP
D) nitric oxide; calcium

Question 33

Neurotrophic factors are generally involved in regulation of

A) long-term changes in gene expression.
B) the rate of cell firing.
C) rapid synaptic events.
D) opening of ion channels.

Question 34

After binding of neurotrophic factors to their respective trk receptors,

A) G proteins are activated.
B) the two trk receptors phosphorylate each other on tyrosine residues.
C) ion channels open.
D) second messenger systems are activated.

Question 35

Studies of structural plasticity often focus on dendritic length, branching patterns, and dendritic spines because

A) these are the primary sites of synaptic input.
B) these areas are easily viewed in human subjects.
C) dendrites are not affected by drugs.
D) the size and location of dendrites are fixed through the human life span.

Question 36

Neurotransmitters are released into the _______, whereas hormones are released into the _______.

A) synaptic cleft; brain
B) bloodstream; synaptic cleft
C) synaptic cleft; bloodstream
D) vesicles; bloodstream

Question 37

_______ is an example of a substance that can act as both a neurotransmitter and a hormone.

A) Acetylcholine
B) Norepinephrine
C) Nitric oxide
D) Cortisol

Question 38

In response to stressors, the adrenal cortex secretes _______ and the adrenal medulla secretes _______.

A) epinephrine; norepinephrine
B) epinephrine; glucocorticoids
C) glucocorticoids; chromaffin cells
D) glucocorticoids; epinephrine

Question 39

In the hypothalamus, secretory neurons, (called _______ neurons), release _______ and _______ into the bloodstream.

A) microcellular; prolactin; vasopressin
B) magnocellular; vasopressin; oxytocin
C) target; oxytocin; prolactin
D) Langerhans; releasing hormones; tropic

Question 40

Releasing hormones from the _______ enter the bloodstream in the median eminence and act on the _______, causing the release of various hormones.

A) anterior pituitary; thyroid
B) posterior pituitary; hypothalamus
C) hypothalamus; anterior pituitary
D) hypothalamus; posterior pituitary

Question 41

Which statement regarding hormones and neuropharmacology is false?

A) Hormones can alter behavioral responses to drugs.
B) Hormone secretion can be altered by psychoactive drugs.
C) Some hormones have psychoactive effects on their own.
D) The effects of hormones on the brain are simple and easy to measure.

Question 42

Steroid hormones bind to _______ receptors, which act as _______ when activated and regulate gene expression.

A) metabotropic; G proteins
B) intracellular; transcription factors
C) tyrosine kinase; transcription factors
D) membrane-bound; G proteins

Question 43

The adrenal gland produces glucocorticoids, which are hormones that are produced in response to stress. The type of glucocorticoid produced depends on species; large mammals produce _______, while most rodent and bird species produce _______.

A) cortisol; corticosterone
B) corticosterone; cortisol
C) estradiol; melatonin
D) melatonin; estradiol

Question 44

The social behavioral neural network, a circuit of vasopressin and oxytocin projections

A) is the same in males and females because they are subject to the same hormones during early development.
B) differs in males and females because the social behaviors it regulates differ between males and females.
C) is the same in both males and females because both all social behaviors are the same in males and females.
D) differs in males and females because brain size differs in males and females.

Question 45

Current research is looking into the use of _______ in the treatment of _______ based on its prosocial effects in humans.

A) antidepressants; Parkinson's disease
B) epinephrine; autism spectrum disorder
C) oxytocin; Parkinson disease
D) oxytocin; autism spectrum disorder

Question 46

List the criteria for classifying a substance as a neurotransmitter.

Question 47

List the key functions of vesicle recycling in synaptic vesicles.

Question 48

Describe three factors that regulate neurotransmitter release.

Question 49

Synaptic plasticity can be studied at three different levels that are not mutually exclusive. List each type and provide an example of each.

Question 50

Briefly summarize five mechanisms by which drugs can alter synaptic transmission, and provide an example of a drug that acts in each manner.

Question 51

Describe the functions of the glucocorticoids, which are steroid hormones.

Question 52

Write a coherent and informative paragraph using the following terms: hypothalamus; posterior pituitary; median eminence; releasing hormones, vasopressin, oxytocin.

Question 53

Describe the mechanism by which vasopressin and oxytocin are released into the bloodstream. What important roles do vasopressin and oxytocin play in human physiology?

Question 54

Researchers are currently investigating the potential of oxytocin to affect social behavior in certain disorders, such as autism spectrum disorder (ASD). What are the challenges of administration of oxytocin? What has the research shown thus far?