physio psych module 2.2
A neuron excretes neurotransmitters through its membrane by a process called ____.
exocytosis
What makes nitric oxide unique among neurotransmitters?
It is a gas.
What happens to acetylcholine after it attaches to a receptor on the postsynaptic cell?
It is broken down into two components.
What happens when a neurotransmitter is released by a presynaptic cell?
The neurotransmitter passively spreads across the synaptic cleft.
What do dopamine, norepinephrine, and epinephrine share in common?
They are all synthesized from the same amino acids.
The basic building blocks for the majority of neurotransmitters are ____.
amino acids
Autoreceptors monitor the ____.
amount of neurotransmitter released
"Second messengers" carry their messages to ____.
areas within the postsynaptic cell
When an action potential reaches the end of an axon, it evokes the release of neurotransmitters by opening ____ channels in the axon terminal.
calcium
When an action potential reaches the end of an axon, the depolarization causes what ionic movement in the presynaptic cell?
calcium into the cell
A metabotropic synapse, by way of its second messenger, ____.
can influence activity in much or all of the postsynaptic cell
Activation of autoreceptors tends to ____.
decrease further neurotransmitter release
The primary method for disposal of peptide neurotransmitters is ____.
diffusion
COMT and MAO are ____.
enzymes that convert catecholamines into inactive chemicals
Releasing hormones are synthesized in the ____ and released in the ____.
hypothalamus; anterior pituitary
Glutamate opens sodium gates, enabling sodium ions to enter the postsynaptic cell. What type of effect is this?
ionotropic
Ionotropic effects ____.
may depolarize or hyperpolarize the postsynaptic membrane
Receptor molecules for neurotransmitters that exert metabotropic effects are proteins that bind to ____ outside the membrane, and attach to ____ inside the membrane.
neurotransmitters; G-proteins
Ionotropic effects are characterized by ____.
rapid and short-lived effects
Which event is most likely to be dependent on ionotropic effects?
rapid muscle contraction
The amino acid tryptophan is the precursor to which neurotransmitter?
serotonin
In general, a single neuron releases ____ neurotransmitter(s) and can respond to ____ neurotransmitter(s).
several; many
Compared to ionotropic effects, metabotropic effects are ____.
slower and longer lasting
What is the synaptic cleft?
the gap between the presynaptic neuron and the postsynaptic neuron
The presynaptic terminal stores high concentrations of neurotransmitter molecules in ____.
vesicles
