PSYC 233 Module 2.2
When an action potential reaches the end of an axon, it evokes the release of neurotransmitters by opening ____ channels in the axon terminal.
calcium
A hormone is a chemical that is ____.
conveyed by the blood to other organs, whose activity it influences
"Transporter" proteins transport neurotransmitters ____.
back into the presynaptic neuron
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 hormone is a chemical that is ____.
conveyed by the blood to other organs, whose activity it influences
Activation of autoreceptors tends to ____.
decrease further neurotransmitter release
COMT and MAO are ____.
enzymes that convert catecholamines into inactive chemicals
Which terms refers to a chemical that binds to another chemical?
ligand
Although slower than an action potential, synaptic transmission is still relatively fast because ____.
the synaptic cleft is very narrow
The presynaptic terminal stores high concentrations of neurotransmitter molecules in ____.
vesicles
The basic building blocks for the majority of neurotransmitters are ____.
amino acids
The primary method for disposal of peptide neurotransmitters is ____.
diffusion
Vesicles are located ____.
in presynaptic terminals
What happens to acetylcholine after it attaches to a receptor on the postsynaptic cell?
It is broken down into two components.
Avoiding foods with lecithin, such as eggs and peanuts, would affect the levels of which neurotransmitter the most?
acetylcholine
A metabotropic synapse, by way of its second messenger, ____.
can influence activity in much or all of the postsynaptic cell
The anterior pituitary is composed of ____ and the posterior pituitary is composed of ____.
glandular tissue; neural tissue
The main advantage of a neuron releasing more than one neurotransmitter is that:
it can send more complex messages
A drug that inhibits the action of the enzyme acetylcholinesterase will have the effect of ____.
prolonging the action of acetylcholine at its synapses
Compared to ionotropic effects, metabotropic effects are ____.
slower and longer lasting
What do dopamine, norepinephrine, and epinephrine share in common?
They are all synthesized from the same amino acids.
Releasing hormones are synthesized in the ____ and released in the ____.
hypothalamus; anterior pituitary
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
Which category of chemicals includes adenosine and several of its derivatives?
purines
What makes nitric oxide unique among neurotransmitters?
It is a gas
What happens when a neurotransmitter is released by a presynaptic cell?
The neurotransmitter passively spreads across the synaptic cleft.
Autoreceptors monitor the ____.
amount of neurotransmitter released
"Second messengers" carry their messages to ____.
areas within the postsynaptic cell
You are eating a food containing tryptophan. What can you consume with it to increase its entry to the brain?
carbohydrates
Neuropeptides are synthesized in the ____.
cell body
Loewi demonstrated that synapses operate by the release of chemicals by ____.
collecting fluid from a stimulated frog's heart, transferring it to another frog's heart, and measuring that heart rate
The catecholamines include ____.
epinephrine, norepinephrine, and dopamine
A neuron excretes neurotransmitters through its membrane by a process called ____.
exocytosis
Glutamate opens sodium gates, enabling sodium ions to enter the postsynaptic cell. What type of effect is this?
ionotropic
A receptor can directly open a channel and thereby exert a(n) ____ effect, or it can produce slower but longer ____ effects.
ionotropic; metabotropic
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
In addition to influencing other neurons, ____ increases blood flow to a specific area of the brain.
nitric oxide
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 effect of a neurotransmitter on a postsynaptic neuron is determined by the ____.
receptors on the postsynaptic membrane