Glia and Neurotransmitters Flashcards
what are the types of glial cells
astrocytes, oligodendrites and microglia
what do astrocytes do (5)
structurally support the neurones provide nutrition to neurones removes excess neurotransmitters buffer K levels help form the BBB
how do astrocytes provide nutrition for neurones
as neurones cant store glycogen, astrocytes take in glucose and store it as lactate. this can then be converted to pyruvate to be transported to the neurones when glucose is low
what neurotransmitter is particularly toxic to neurones
glutamate
how do astrocytes help form the blood brain barrier
they help form the tight junctions between endothelial cells
what do oligodendrites do
myelinate the axons in the CNS to give insulation
what cells myelinate the neurones in the PNS
Schwann cells
true or false: each oligodendrite can only myelinate one axon at a time
false- they can myelinate may at one time
what do microglia do
they recognise foreign bodies and become activated into phagocytes
describe the release of neurotransmitters at synapses
depolarisation in the pre-synpatic bulb causes the influx of calcium ions.
Ca ions causes the vesicles containing the neurotransmitter to fuse with the pre-synpatic membrane to be released into the synaptic cleft.
the neurotransmitter then binds to receptors on the post-synaptic membrane to cause either activation/inhibition.
true or false; glutamate is excitatory
true
what receptors does glutamate bind to
GPCRs, AMPA and NMDA
describe what happens when glutamate binds to AMPA receptors
causes fast depolarisation as the receptors are linked to Na/K channels so sodium moves into the cell.
the depolarisation also allows activation of the NMDA receptors
when do NMDA receptors become activated
when glutamate binds and when the neurone is depolarised due to AMPA receptors
what does activation of NMDA receptors lead to
opening of calcium channels leads to calcium influx
what is the calcium influx through NMDA important for
learning and memory
why is too much glutamate toxic to cells
lots of AMPA are activated so the neurones depolarise more - therefore, more NMDA are activated so lots of calcium is taken into the cell which is excitotoxicity
name 3 types of amino acid neurotransmitters
glutamate, GABA and glycine
what is excitatory postsynaptic potential
where depolarisation occur in the post-synpatiic bulb following neurotransmitter release
what is inhibitory postsynaptic potential
where hyper polarisation occurs in the post synaptic bulb following neurotransmitter release
how do GABA and glycine cause hyper polarisation in the post-synaptic bulb
they are linked with chloride channels so the influx of chloride ions causes hyperpolarisation
what drug types enhance GABA receptors
barbiturates and benzodiazepines
what are drugs which enhance GABA receptors used to treat
epilepsy, anxiety and insomnia
where is acetyl choline released from in the CNS
Nucleus basalis
where does acetyl choline travel to in the CNS
hippocampus and cortex
which neurones are the first to die in Alzheimer’s
nucleus basalis
what drugs are given to help the symptoms of Alzheimers
cholinesterase inhibitors
where is dopamine released from in the CNS
mesocortical pathway, mesolimbic pathway and nigrostriatal pathway
what is the nigrostriatal pathway involved in
motor control
what neurones are the first to die in Parkinson’s
nigrostriatal pathway
what is the treatment for Parkinson’s
L-DOPA with carbidopa
why is carbidopa given in Parkinsons disease
as this prevents the conversion of L-DOPA to dopamine in the peripheries as dopamine cant cross the BBB
what happens to neurotransmitters in schizophrenia
too much dopamine
where is NA released to in the CNS
cortex, hippocampus and cerebellum
where is NA released from
locus ceruleus in the brainstem
what does serotonin help control
sleep and mood
