Neuronal Communication Flashcards
What are the similarities between sensory and motor neurone
Both have:
Dendrites
Cell Body w/ nucleus
Myelin sheath covered w/ shwarn cells
What are roles of synapses
Filters out low stimulation
Ensures impulse travels in 1 direction
one neurone connects to many neurones
How to tell for big stimulation
High frequency but same magnitude of action potentials
What is function of myelin sheath and how does it achieve it
Speeds up conduction of action potetnial as depolarisation only occurs at nodes. Saltatory conduction (action potential jumps from node to node) Longer section with no Na+ channel. Schwarn cells produce myelin sheath to insulate neurone
Wraps around neurone but not nodes of ranvier
What are transducers and what does deformation of it do
Converts energy into another form of energy
Deformation causes more Na+ channels to open hence more gaps in the bilayer
How is resting potential maintained
Voltage gated Na+ channels close as memb. becomes less permeable to Na+ hence less Na+ diffuses back in
What occurs in a synapse
Ca2+ channels open which csuse Ca2+ to diffuse into presyanptic knob and diffuse causing vesicle containg acetylcholine to move towards the presynaptic membrane and fuse with it. Adenylcholine is released in the Synaptic cleft where it diffuses across it and binds with receptors on post synaptic membrane. Neurotransmitters broken down in syanptic cleft
What are differences between sensory and motor neurone
Sensory contains shorter axon wheras motor contains longer axon
Motor has cell body in C.N.S wheras sensory does not
Sensory has dendrons wheras motor does not
How does the neurone ensure travel in only one direction
ONLY presynaptic knob produces actylcholine
What is refractory period and why is it important
After A.P Memb. cant be stimulated as Na+ channels are recovering
Important as ensures discrete impulses are produced
Ensure A.P travels in only one direction
Why is transmission slower in absence of nodes
As whole axon needs to be depolarised
How does a statocyst act as a transducer
Kinetic energy converted to electrical energy –> Cuases movement of Statolith hairs. Mmebrane of statolith hair depolarises
What is structure of myelin sheath
Myelin sheath formed by schwarn cells wrapped around axon except the nodes of ranvier
Describe what happens during resting-> depolarisation->repolarisation->hyperpolarisation
Resting -> VOLTAGED GATED NA+ CHANNEL CLOSED
-70mV and sodium potassium pump function
Action -> Depolarisation and threshold potnetial (-55mV) reached where Na+ ION CHANNEL OPEN ALLOWING NA+ TO DIFFUSE IN CAUSING CELL TO BECOME +40MV
Repolarisation-> NA+ CHANNEL CLOSED AT +40MV AND VOLTAGED GATED K+ channels OPEN allowing MORE K+ to diffuse out
Hyperpolarisation -> When charge goes LOWER than -70mV sodium potassium pump needs to work to bring it back up to -70mV
How does ACh have an effect on cells on skin
Ach secreted in skin and binds onto receptors on plasma memb.
