Module 2.1 and 2.2 Quiz
dendrites
Many neurons release neuropeptides mostly from the ____.
epinephrine, norepinephrine, and dopamine
The catecholamines include ____.
it is broken down into two components.
What happens to acetylcholine after it attaches to a receptor on the postsynaptic cell?
The neurotransmitter passively spreads across the synaptic cleft.
What happens when a neurotransmitter is released by a presynaptic cell?
It breaks acetylcholine down into components for recycling.
What is the function of the enzyme acetylcholinesterase?
Spatial summation depends on contributions from more than one sensory neuron.
What is the primary difference between temporal summation and spatial summation?
sensory neuron, interneuron, motor neuron.
What is the proper ordering of a reflex arc?
he gap between the presynaptic neuron and the postsynaptic neuron
What is the synaptic cleft?
It is a gas.
What makes nitric oxide unique among neurotransmitters?
back into the presynaptic neuron
"Transporter" proteins transport neurotransmitters ____.
depolarization; hyperpolarization
An EPSP is to ____ as an IPSP is to ____.
spontaneous firing rate
Even at rest, most neurons have periodic production of action potentials, known as the ____.
They decay over time and space.
Which statement is TRUE of EPSPs?
it can send more complex messages
The main advantage of a neuron releasing more than one neurotransmitter is that:
Both enable a reflex to occur in response to weak stimuli.
What do temporal summation and spatial summation have in common?
decrease further neurotransmitter release
Activation of autoreceptors tends to ____.
enzymes that convert catecholamines into inactive chemicals
COMT and MAO are ____.
slower and longer lasting
Compared to ionotropic effects, metabotropic effects are ____.
purines
Which category of chemicals includes adenosine and several of its derivatives?
collecting fluid from a stimulated frog's heart, transferring it to another frog's heart, and measuring that heart rate
Loewi demonstrated that synapses operate by the release of chemicals by ____.
temporal summation
A certain weak stimulus produces no reflexive response, but a rapid repetition of that stimulus may produce such a response. What is this phenomenon called?
similarly to metabotropic neurotransmitters
Hormones exert their effects ____.
synapses
Specialized junctions between neurons are called ____.
record depolarizations of the postsynaptic neuron
To measure temporal summation in single cells, researchers ____.
the opening of sodium channels
What causes an EPSP?
the combined effects of EPSPs and IPSPs
What determines whether a neuron has an action potential?
prolonging the action of acetylcholine at its synapses
A drug that inhibits the action of the enzyme acetylcholinesterase will have the effect of ____
conveyed by the blood to other organs, whose activity it influences
A hormone is a chemical that is ____.
can influence activity in much or all of the postsynaptic cell
A metabotropic synapse, by way of its second messenger,
exocytosis
A neuron excretes neurotransmitters through its membrane by a process called ____.
When the interneuron sends excitatory messages to one, inhibitory messages go to the other.
A normal, healthy animal never contracts the flexor muscles and the extensor muscles of the same leg at the same time. Why not?
ionotropic; metabotropic
A receptor can directly open a channel and thereby exert a(n) ____ effect, or it can produce slower but longer ____ effects.
IPSP
A temporary hyperpolarization is known as an ____.
the synaptic cleft is very narrow
Although slower than an action potential, synaptic transmission is still relatively fast because ____.
acetylcholine
Avoiding foods with lecithin, such as eggs and peanuts, would affect the levels of which neurotransmitter the most?
excitation; inhibition
Depolarization is to ____ as hyperpolarization is to ____.
ionotropic
Glutamate opens sodium gates, enabling sodium ions to enter the postsynaptic cell. What type of effect is this?
interneurons
In a reflex arc, the coordination between contraction of certain muscles and relaxation of others is mediated by ____.
nitric oxide
In addition to influencing other neurons, ____ increases blood flow to a specific area of the brain.
several; many
In general, a single neuron releases ____ neurotransmitter(s) and can respond to ____ neurotransmitter(s).
hyperpolarize the postsynaptic cell
Inhibitory synapses on a neuron ____.
may depolarize or hyperpolarize the postsynaptic membrane
Ionotropic effects ____.
rapid and short-lived effects
Ionotropic effects are characterized by ____.
behavioral observations
On the basis of what evidence were the properties of synapses first inferred?
neurotransmitters; G-proteins
Receptor molecules for neurotransmitters that exert metabotropic effects are proteins that bind to ____ outside the membrane, and attach to ____ inside the membrane.
hypothalamus; anterior pituitary
Releasing hormones are synthesized in the ____ and released in the ____.
areas within the postsynaptic cell
Second messengers" carry their messages to ____.
the speed of reflexive responses
Sherrington deduced that transmission at a synapse must be slower than conduction along an axon. This was based on what kind of evidence?
multiple weak stimulations that occur at the same time
Spatial summation refers to ____.
time; location
Temporal summation is to ____ as spatial summation is to ____.
rapid succession of subthreshold excitation
Temporal summation most likely occurs with ____.
ratio of EPSPs to IPSPs
The "decision" for a neuron to fire is determined by the ____.
its rate of producing action potentials even when it is not stimulated
The "spontaneous firing rate" of a neuron refers to ____.
glandular tissue; neural tissue
The anterior pituitary is composed of ____ and the posterior pituitary is composed of ____.
amino acids
The basic building blocks for the majority of neurotransmitters are ____.
a reflex arc
The circuit from sensory neuron to muscle response is called ____.
receptors on the postsynaptic membrane
The effect of a neurotransmitter on a postsynaptic neuron is determined by the ____.
EPSPs are subthreshold events that decay over time and space
The primary difference between an EPSP and an action potential is that ____.
diffusion
The primary method for disposal of peptide neurotransmitters is ____.
calcium into the cell
When an action potential reaches the end of an axon, the depolarization causes what ionic movement in the presynaptic cell?
nitric oxide
Which neurotransmitter is released by stimulated neurons to dilate the blood vessels?
rapid sequence of EPSPs
Which pattern of post-synaptic excitation will most likely result in an action potential?
chloride ions entering the cell
Which process will most likely result in an IPSP?
EPSPs increase the frequency.
Which statement is TRUE about the spontaneous firing rates of neurons?
Transmission between neurons at synapses is slower than along axons.
Why is the speed of conduction through a reflex arc slower than the speed of conduction of an action potential along an axon?
rapid succession of subthreshold excitation
temporal summation most likely occurs with ____.