Study Guides (238,096)
Canada (114,916)
Biology (368)
BIOL 361 (14)
All (6)

Bio361-signal transduction + nervous system

1 Page
Unlock Document

University of British Columbia
BIOL 361

Neuroncable propertiesvariationsshape of APs vary among neurons from into the mem capacitortime constanttime needed for the mem capacitor to diff organismsbtwn types of neruons from the same organmsamong APs wchargelargerlonger it will take for the mem to reach a given mptime taken in the same neuron under diff physiocdtnsresult of the diversity of the for the mp to decay to 37 of its original value to reach 63 of its max molecular properties of the VG Na and Kchannels among neuronslack valueincrease in either mem resismem capacitance will increase the time VG K channelsdo not have afterhyperpolarizationrepolarized by Kconstant of the memdelaying current ow across the memhas important movemnt thru Kleak channelsisoformsions channelsslightly diff consequences for temporal summationsmallpotentials will decay rapidlymolecular variants of the same proteinencoded by diff genessequence less likely to be able to sum up provide a suprathreshold potenlargedecay variationlead to functions diff that chnge the way neurons workdiff isoforms slowlymore likely to overlap in timesum to a suprathreshold potenonly for VG Kchannelsdiff shapes during repolarizing phase of AP in diff cells once the capacitor is fully charged does current begin to ow across the tissuesorganmsVG Kchannelsstrong inuence on the excitability of the memalter mpelectrotonic current spread is delayedsmaller the time cellAPdurationAPratedelayed rectiersrespond relatively slowly to chnges constant of the memthe faster the mem can depolarize by a given in mpincreasing the length of APVG Nachannelsless diverseneurons that amountthe greater the rate of electrotonic current spreadAP have a higher density of itmore channels are available to open given propagation3main factors inuence the speed of AP propagation1kinetics stimulus intensitymore Naentering cellwill have a lower threshold that the of the VG channelsAP propagates fasterhigher temp as open ones with lower densitythe balance pt btwn dissipationinux of Naions is fasterwarmer temp2any factors that can increase the speeddistance of more easily reachedlower lvl of depolarizationa smaller graded poten electrotonic current spread increases the speed of conductiondependent on can excite a neuronshorter relative refractory period more diverse VG the alength constantbtime constant of the axon axons that activate channels are required to build a highly complex nervous systemVG musclesfar end of the mantle cavity have very large diametersaxons that Ca2channelsopenthe same time as VG NachannelsCa2enter cell and activate muscles in the region of the mantle cavity closest to the CNS have cause depolarization but inux is slowermore sustainedlast longersmaller diameters length constant of the membrane increases as mem slow down the rate which AP can be generated by prolonging the resis increases but decreases as intracellular resis increasesmembrane refractory period2strategies to increase AP conduction speedmyelinationresistanceinversely proportional to the SA of the membraneSAincreases increase the diameter of the axonmyelinated incr diameterhigh and so does the of leak channelsgreater ion ow across the memmem conduction velocitygiant axonslarge diameter axoncable properties of the resis decreasesradius of the axonproportional to the memresisdiameter axondictate current ow along the axoncurrenta measure of the amt of increases and membrane resistance decreasesvolumerelated to the charge moving past a point in a given amt of timea function of the drop in volume of the axonvolume increases and intracellular resistance Volt across the circuitresistance of the circuitOhms lawdescribes the decreasesintracellular resis decreases in proportional to the radius of the relationship btwn currentvoltagevoltagea measure of the energy carried by axon squaredaxon radius increasesboth memintracell resis decreasesa unit of chargevolt drop across the circuitdiff in voltage btw 2ptsa measure decrease intracell resisincrease length constincrease conduction speedof the E available to move charge from 1pt to the otherpotential Edecrease mem resisdecrease length constslowing conduction resistancea measure of the force opposing the ow of electrical current speedincreasing the radius of an axon
More Less

Related notes for BIOL 361

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.