CHAPTER 2 - Chemical Events at the Synapse (Module 2.2) Flashcards
(57 cards)
who is otto loewi?
he is the guy who discovered the chemical transmission of nerve impulses with a frog’s heart
What was Loewi’s evidence that neurotransmission depends on the release of chemicals?
When Loewi stimulated a nerve that increased or decreased a frog’s heart rate, he could withdraw fluid from the area around the heart, transfer it to another frog’s heart, and thereby increase or decrease its rate also.
Blood flow increases to the most active brain areas. How does the blood “know” which areas are most active?
In a highly active brain area, many stimulated neurons release nitric oxide, which dilates the blood vessels in the area and thereby makes it easier for blood to flow to the area
what are neurotransmitters?
chemicals released by a neuron that affects another neuron
what is nitric oxide?
it is a gas released by many local neurons that is poisonous in large quantities yet neurons contain an enzyme that allows them to make it efficiently
what do neurons synthesize almost all neurotransmitters from?
amino acids
what is epinephrine, norepinephrine and dopamine known as?
they are known as catecholamines because they contain a catechol group and an amine group
Name the three catecholamine neurotransmitters.
Epinephrine, norepinephrine, and dopamine.
Do not confuse the term catecholamine with acetylcholine
what is exocytosis?
bursts of release of neurotransmitter from the presynaptic neuron
When the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neurotransmitter?
Calcium
what are the channels controlled by a neurotransmitter called?
transmitter-gated or ligand-gated channels
what is a ligand?
it is a chemical that binds to something
what is the most abundant neurotransmitter in the nervous system?
glutamate
Why does the nervous system use so many chemicals, if they all produce the same type of message?
they do not produce the same type of message since it is more complicated and more varied, when a neurtransmitter attaches to its receptor, it may exert a IONOTROPIC EFFECT or a METABOTROPIC EFFECT
what is a G protein?
a protein coupled to guanosine triphosphate (GTP), an energy-storing molecule
what are neuropeptides also referred to as?
neuromodulators, because they have properties that set them apart from other transmitters
How do ionotropic and metabotropic synapses differ in speed and duration of effects?
Ionotropic synapses act more quickly and more briefly
What are second messengers, and which type of synapse relies on them?
Second messengers are chemicals that alter metabolism or gene expression within a postsynaptic neuron.
At metabotropic synapses, the neurotransmitter attaches to a receptor and thereby releases a second messenger
How do neuropeptides compare to other transmitters?
Neuropeptides are released only after
prolonged stimulation, but when they are released, they are released in large amounts by all parts of the neuron, not just the axon terminal.
Neuropeptides diffuse widely, producing long-lasting effects on many neurons.
How do LSD, nicotine, and opiate drugs influence behavior?
SD binds to one type of serotonin receptor.
Nicotine binds to one type of acetylcholine receptor.
Opiates bind to endorphin receptors.
what is reuptake
is a biological process in psychology that involves the reabsorption of neurotransmitters after they have transmitted a neural impulse
what does reuptake occur through?
special membrane proteins called TRANSPORTERS
what inhibits the transporters for dopamine, serotonin, and norepinephrine
stimulant drugs, including amphetamine and cocaine
What happens to acetylcholine molecules after they stimulate a postsynaptic receptor?
The enzyme acetylcholinesterase breaks acetylcholine molecules into two smaller molecules, acetate and choline, which are then reabsorbed by the presynaptic terminal
