intro neuro Flashcards
what is convergence?
neurone has synaptic input from a variety of neurones
what is divergence?
neurone provides synaptic input to many other neurones
what is spatial summation
many neurones exert same effect on the post synaptic membrane
what is temporal summation
several APs arrive in succession to have a greater effect than just one AP
how do EPSPs and IPSPs decay?
with exponential time course
what do IPSPs lead to?
hyperpolarisation on the post synaptic membrane
what are the 3 classes of neurotransmitter?
amino acids; amines and purines; peptides
examples of amino acid neurotransmitter
glutamate, GABA, glycine
examples of amines and purines neurotransmitters
Ach, NA, 5HT, ATP
Examples of peptide neurotransmitters
CCK, substance P, vasopressin
what are fast receptors called and how do they work
Ionotropic, directly linked to ion channels
what are slow receptors and how do they work
metabotropic, coupled to effector ion channel
what are the 3 types of glutamate receptor?
NMDA glutamate receptors, non NMDA receptors and metabotropic receptors
which glutamate receptors are fast receptors
NMDA and non NMDA
how does the metabotropic glutamate receptor work
more long term effects. linked to G proteins and 2nd messenger coupling.
whats the difference between NMDA and non NMDA receptors
non NMDA is not affected by NMDA, activated by AMPA and kainite. NMDA binds NMDA receptor
what are the 2 types of GABA receptor
GABAa and GABAb
what is the structure of GABAa
2 alpha, 2 beta, 1 gamma
how does GABAa work?
opens channel permeable to Cl- membrane hyperpolarises
how does GABAb work?
activate K+ channels causing hyperpolarisation and inhibits APs
what is the structure of GABAb?
7 transmembrane domains which are coupled to G proteins
what effects do ACHrs have ?
both inhibitory and excitatory, mainly excitatory
how do mACHrs work?
coupled to G proteins. quite slow
what are the subtypes of mACHrs
M1-5
what are M1,3,5 coupled to?
phospholipase C
what are M2,4 coupled to?
negatively coupled to adenylyl cylcase
what are the major subtypes of dopamine receptors
D1 and D2
where are dopamine receptors found
throughout CNS, in mesostriatal tract and nigrostriatal tract
what does degeneration of tracts associated with dopamine lead to
parkinsons
what type of transmission are serotonin receptors
metabotropic
Are 5HT1 receptors inhibitory or excitatory
inhibitory (5HT2 excitatory)
what stain can be used for CNS tissue
Weigerts stain
what colour does white matter stain
stains darkly as myelinated it contains lipids which the stain is for (grey matter unstained)
is there connective tissue in the CNS
NO CONNECTIVE TISSUE IN CNS
what is a fascicle
contains bundles of axons
how much of brain is grey matter and how much oxygen does it use
40% of brain. uses 96% of O2
what fibres interconnect on the same side
association fibres
what fibres interconnect on the opposite side
commissural fibres
are there more neurones or neuroglial cells in the CNS
10x more neuroglial cells
what are the neuroglial cell types
oligodendrocytes, astrocytes, ependymal cells, microglia
what is the function of oligodendrocytes
forms myelin sheath, in 10-15 axons
what are the functions of astrocytes
blood brain barrier, regulate K+, glutamate and Ca2+, produce growth factors for the production of neurones, help in neural migration, some become neurones, synapse formation
what is the function of microglia
defence (mobile)
what is the function of ependymal cells
line ventricular system
what cells line the entire CNS part of the blood
endothelial cells
how are neurones grouped
nuclei, laminae or reticular formation
