A2 Unit F214 - Communication, Homeostasis and Energy
Summary
Summary OCR A Level Biology A* Neuronal Communication Detailed Notes
20 views 0 purchase
Course
A2 Unit F214 - Communication, Homeostasis and Energy
Institution
OCR
These A-Level Biology notes are designed for students aiming for top grades and a future in medicine. They are both aesthetic and detailed, offering comprehensive coverage of the syllabus while being visually engaging.
Comprehensive Coverage: Every topic is fully covered, directly aligned with t...
A2 Unit F214 - Communication, Homeostasis and Energy
All documents for this subject (31)
Seller
Follow
alevelrevisionresources
Content preview
s 3 I neurones
specialisednervoussystem
cents
ie
initialis niiatiifuisesaroundthebody all with along
fibre axon cellbodywithnucleus organelles axonterminalwithnerveendings to allow
connections withmanyothern ewones receiveimpulses toroomnetworks communication
some are myelinated axoninsulated by myelinsheathformedby specialised Schwanncells
thatwraparoundneurone withsmalluninsulatedsections nodesofRanvier forcesimpulses to
jumpbetweennodes speedsuptransmission us uninsulated impulsetravelsalongwholelength
sensory i ibÑybranchesof inmiddleofcellsinglelongdendron axon
Fattyimpulsesreceptors cus
is iii iii it iii t.iiii.in ii iiiniiiinii.iianiii aiiiaa mina
5 3 2 mammalian sensory receptors
res en itioione'iiiiiiiinerayineieariiaiimpu
T.is ni Isa nanansei
ne jon it.com
laws
cones inretinadetect lightintensit
photoreceptors light eye lightenergy electrical energy
chemoreceptors chemicals hypothalamus chemicalenergy electrical detectchemicals bodytempinblood
mechanoreceptors stretching bloodvessels kineticenergy electrical detectmusclestretch mechanicalstrain
baroreceptors bloodpressureaortacarotidartery kineticenergy electrical directlevelas stretch ofvascularwalls
osmoreceptors bodytwids hypothalamus chemicalenergy electrical detectwater torrentofblood
auditoryreceptors sound ear soundkinetic electrical detect sound movement andorientation
Pacinian corpuscles Pacinian corpusclesfoundatendof
mechanoreceptors found sensoryneuronaxons madeofmany
deepin skinastingers layersof membraneseparatedbyge
solesofnet joints tendons containing Nations
respond to
ligaments 1 if no pressure applied Natremain
pressurechanges onoutsideof membrane resting
to potential maintained
ieii.int 9ie'raio
potential nervousimpulse
2 whenpressureapplied sheren medi
sodium channelsopen Natentersa
producedbysensory 3 Nat Howsintoneurone establishing
receptoraftere nergyconversion an electrical potential disterence acr
theaxon membrane generatorpole
s 3 3 Resting potentials
in a resting axon notcurrently transmitting impulses inside theaxon has a Ove electricalpotential vsoutsi
this differente theresting potential potential difference 70mV established maintained by 2 factors
Activetransport of Natand kt carrierproteins sodium potassiumpumps use ATPtoactively
nsport swatout of the axon forevery 2kt they activelytransportin higherconc of
veionsoutsideaxon maninside electrochemical gradient establishedby movement of ionsvia
di in potassiumpump 2 Differentialmembrane permeability selentiveproteinchannelsin cell
racemembraneofneurons allowsodiumand potassiumionstomoveacrossby facilitated
fusion But proteinchannels are less permeable to Nat man kt so kt ions can diffuse
okdowntheirconc gradient outof meaxon at a fasterrate mansodium ions
5 3 4 Action Potentials
nervesignals causedby rapidmovement of Nat and kt acrossmembraneofaxon the
resultantbriefchange in distributionof electri inargeacross thecellsurfacemembrane
voltage gated channel protein open close depending on electrical potential across axon membrane letsionsthro
e SEMI note c animism io e imEtn inroco
a i i
iii iii is n i
morechannelsopen more Nat moredepolarisation positivefeedback actionpotentialreaches potentialof 30mV
ii
3 REPOLARISATION 1msafterpotentialdifferencereaches 30mV all Natchannelsclose AND kt voltagegatedchannel
rokins insectionofaxonmembrane open allows diffusion of kt out downconc gradient returns p.D.tonormal 70m
4 HYPERPOLARISATION K channels areslowto store toomany kt ditureoutofnewore negativereaba
potentialdifference belones brieflymore ve mannormal restingpotential 70mu
S RESTING POTENTIAL when kt channelsclose he sodium potassium pumprestoresrest po ii
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller alevelrevisionresources. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.37. You're not tied to anything after your purchase.
