for exam Flashcards
what is axonal transport?
transport of proteins through microtunules in acons
fast approx 1000mm/day
cna ba anterograde and reterograde
what is the acon hillock
the part of the axon which first emerges from the soma
what is the axon proper
the main body of the axonwhat are the acon terminalsthe very end o the acon where boutons are formed this is what synapses start from
what are the acon collaterals
banches o the axon so just before the terminals
what ae the five features through which neurons can be classified and what are the options?
shape: stellate or yramidal(cal also be spiny
axons: golgi 1-long golgi2-lcal
number of neutrites: unipolar bipolar or multipolar
connections: primar sensory-connected to sensory surfaces eg skin and retina motor-conneted to muscle interneurons-connected to other neurons
which cells produce myelin in the cns
oligodendrocytes
which cells produce myelin in the pariforal nervous system
schwan cells
describe the shape and structure of an strocute
star shaped and contains few organelles and microglies
what is the functio of astrocytes
povide mechanicl and metabollic support whilst reguating the flow of ions in extracellular fluid and being inbolved in repair
they are most numerous in brain
what is the structure of olligodendrocytes?
numerous organeles and microtubules as they make myelin and are involved in repair processes in th cns
what does the spinothalamic pahwa signal?
pain
a higher diameter of the axon mens ther i Ales or B more resitance
less
where are neuropeptides synthesised?
vell body
what percentage of all synapses do chemical synapses mae up?
95%
how long is the synaptic delay ?
0.5ms
which neurotransmitter does currarie compete with and at which receptor?ps its a reversible antagonit…
acetlchlllline t the nicotinic receptor
what are the efects of curarie?
paralasys as ist prevents the neurotransmitte at he neuromuscular unction
where are inhibitory chemical snapses motly located?
around cell body and axon hillock
what is postsynaptic inhibition
inhibitor transmitter reduces the likelihood of an acin potentil by causing hyperpolarisation of the nerve membrane making it more negative
what is presynaptic inhibition
special kind of inhibition
occurs at axo axonic axon terminals
these are terminals that are presynaptic and post syaptic
presynaptic inhibition ifs the reduction in amount of neurotransmitter relased
where is presynaptic most common?
brain and spinal cord
where are excitatory synapses located
dendritic tree
where are small molecle neurotransmitters snthesised?
axon terminals
why are calcium ions important to transmitter release?
when the presynaptic membran depolarises calcium ion voltage gated ion channels open this stmultes transmitter release.
if calcium is replaced with another ation release is blocked
what does it mean that transmitter relase is quantial
small depolarisations occur with transmitter release known as mepps
when one packet of transmitter isreleased there is a uniform amplitude released when two packets are released this amplitude is doubled
it is now known that the amount o transmitter released is quantial
what are auto receptors, where are they located and what do they regulate?
they are located at the presunaptic terminal sometime. they are activated with transmitter relase and regulate transmitter production
what are ionotropic receptors and wht are their function on the post synaptic membrane?
they are basicallyion channel receptors
wehn the transmitter binds the channel opens letting the flow of ions into the nerve cell
action isfast an ecample is the icotinic acetylchollin receptor
what is a metabotrophic receptor how does it work and what is its function?
an example is a g protein coupled receptor
works slowl as its not directly linked to an ion channel
it uses second messenger moleules such a s Cuclic amp which is part of an effector system which in turn actiates ion channels
this process is slow hich eplains the slow naure of neuro modulators
what are the processescalled that are intiated by second messenger moleculus and how lon do the changes alst
the changes are usually permenant and these cascades are imporant in learning and memory
cascades can caus other effecs than just opening ion channels
what are ther three methods of inactivation at the post snaptic membrane?
1diffusion
2 re uptake ie with monoamines these are reuptaken and recycled
3.enxyme breakdown
what is aldoterone and which type of response to challenge is it ie short long or medium term
aldosterne encourgesretention of salt and water and is a medium term response to challenge ie blood loss in particular
