Brain Bee Chapter 3 - Jacey Flashcards
Action Potentials are transmitted along axons to specialized regions called ______.
synapses
In a special region called synapses, the axons contact the _______ of other neurons.
dendrites
What do the dendrites of other neurons consist of?
presynaptic nerve ending
The presynaptic nerve ending is separated by a small ___ from the ____-________ _________.
gap, post-synaptic component
State the location of a presynaptic nerve ending
dendritic spine
true or false? the electrical currents are responsible for slowing down the action potential along axons that can bridge the synaptic gap.
false
Transmission across this gap is accomplished by chemical messengers are called
____________.
neurotransmitters.
what are neurotransmitters stored in?
synaptic vessels
true or false?
there are vesicles for storage and vesicles closer to nerve endings that are
ready to be released.
true
The arrival of an action potential leads to the opening of _______ that lets in _______.
ion channel, calcium
what activates enzymes that act on a range of presynaptic proteins?
The arrival of an action potential
state an example of exotic protein names xD
tagmin, snare, brevin
True or false: Neuroscientists have discovered (a long time ago) that these presynaptic proteins race around tagging and trapping others, causing the releasable synaptic vesicles to fuse with the membrane, burst open, and release the chemical messenger out of the nerve ending.
false, neuroscientists recently discovered this.
how wide is the synaptic cleft?
20 nm (nanometres)
when do synaptic vesicles reform?
when the membranes are swallowed back into the nerve ending
What is the main excitatory neurotransmitter?
glutamate
define inhibition:
need to ask Sophia
True or False? At inhibitory synapses, activation of receptors leads to the opening of ion channels that allow the
inflow of negatively charged ions giving rise to a change in membrane potential called an inhibitory post-synaptic potential (ipsp)
true
does IPSP oppose membrane depolarisation and therefore the initiation of an action potential at the cell body of the receiving neuron?
yes it does
is synaptic transmission a fast process or slow process?
very fast process
the time taken from the arrival of an action potential at a synapse to the generation of an EPSP in the next neuron is very rapid - ____ of a second.
1/1000 of a second
must different neurons time their glutamate to others within a short window of time/opportunity?
yes
if the epsps in the receiving neuron are going to
add up to trigger a new impulse - _______ also has to operate within the same interval to be effective in shutting things down
inhibition
Name two inhibitory neurotransmitters:
GABA and glycine
true or false? the existence of a large number of other chemical agents released from neurons and many of these affect neuronal mechanisms by interacting with a very different set of proteins in the membranes of neurons called metabotropic receptors.
true
do metabotropic receptors contain ion channels?
Are they localized in the synapse region?
no, no
define neuromodulation:
the action of metatropic receptors
where are metabotropic receptors usually found?
complex particles linking the outside of cell.
when a neurotransmitter is recognized and bound by metabotropic receptor, bridging molecules called
_- _______ membrane bound enzymes are collectively triggered.
G-Proteins
what does ionotropic receptors do?
opens a door for ions in the membrane
what does a transmitter do?
kick-starts intracellular second messengers into
action
Name the effects of neuromodulation:
ion channel changes, receptors, transporters and even the expression of genes.
do the effects of neuromodulation have profound effects on impulse through neural networks?
yes!!
name some messengers acting on G-Protein.
acetylcholine, dopamine and noradrenaline
how many noradrenaline neurons are there in the human brain?
1600
do noradrenaline neurons only send axons to the brain?
no!! they send axons to all parts of the brain and spinal chord.
do neuromodulatory transmitters send out precise sensory info?
nope.
why is noradrenaline released?
in response to various forms of novelty and stress and helps organize complex responses.
what does dopamine do?
makes certain situations rewarding by acting on brain centres associated with positive emotional features
what does acetylcholine do?
acts on ionotropic and metabotropic receptors
true or false? The first
neurotransmitter uses ionic mechanisms to signal across the neuromuscular junction from motor neurons to striated muscle fibres
true!
