Glia Flashcards
What do glia do ?
support the network of neurones . Nourish, insulate and remove waste products
What do astrocytes do?
the most abundant glia : Structural support Nutrition Remove neurotransmitters maintain ionic environment help form BBB
What provides immune response in neurones ?
Microglia
What are oligodendrocytes ?
provide insulation to neurones
How do astrocytes provide energy for neurones ?
neurones cant store/produce glycogen
Astrocytes produce and shuttle it with glucose to the neurone
How do astrocytes interact with neurotransmitters?
help keep ExCellular conc of neurotransmitters (glutamate) low via intake from transmitters
What do astrocytes help maintain in terms of ions levels?
buffer the conc of K+ . k+ increased in high neuronal activity and astrocytes take in K+.
What myelinates neurones in the CNS? what about the PNS?
CNS = Oligodendrocytes PNS = Schwann
How do microglia cells work?
recognise foreign material , expand and phagocytose
what are the 2 functions of the BBB?
Limit diffusion from blood to brain ECF
Maintain environment of neurones
What 3 functions do brain capillaries have ?
Tight junctions between endothelial cells
basement membrane surrounding capillary
end feet of astrocyte processes
What is transported across the BBB?
Glucose, amino acids and potassium
How is the CNS immune privileged ?
Rigid skull = not much volume increase
does not undergo rapid rejection of allografts
Microglia = antigen presenting cells
T cells can enter the CNS but inhibits the inflammatory T-cell response
What are the 4 main sections of the neurone ?
Cell soma (body)
Dendrites
Axon
Terminals (Pre/postsynaptic)
how is neurotransmitter released ?
Depolarisation in terminal = opening of VGCC . Ca2+ entry making vesicles fuse and release transmitter
diffuse across synaptic cleft and bind to receptor in postsynaptic membrane
what are the 3 types of neurotransmitters and name an example of each type.
Amino acid = Glutamate, GABA, glycine
Biogenic amino = ACh , NA, Dopamine, serotonin and histamine
Peptides = CCK, Somatostatin
what are the excitatory and inhibitory amino acid neurotransmitters ?
Excitatory = Glutamate Inhibitory = Glycine , GABA
What are the ionotropic glutamate receptors and what do they do?
AMPA - Na+/K+
Kainate - Na+/k+
NMDA - Na/k/Ca
allow the following ions to be permeable which depolarises = increases excitabilty
What do glutamatergic Metabotropic receptors do?
G- coupled protein receptor-
IP3 and Ca2+ increase
inhibition of adenylate cyclase = decrease cAMP
What do excitatory neurotransmitters do ?
depolarisation = EPSP leads to more APs
What do AMPA receptors do ?
Initiate the fast depolarisation fro influx of Na+ when glutamate attaches . Allow NMDA receptors to activate
What do NMDA receptors do and how are they activated?
NDMA activation requires Glutamate and depolarised post synaptic neurone
Allow Ca2+ entry and causes induction of LTP = important role in learning and memory
How can AMPA receptors be affected from NDMA receptors ?
AMPS can up regulate when there is high activation of NMDA receptors
What happens when too glutamate is produced?
Too much Ca2+ entry via NMDA so leads to excitotoxity
