Video: Yuav ua li cas muaj peev xwm tsim tau?
2024 Tus sau: Miles Stephen | [email protected]. Kawg hloov kho: 2023-12-15 23:36
Ib tug neuron uas emits ib peev xwm ua , los yog paj hlwb impulse, feem ntau hais rau "hluav taws". Tej yam peev xwm ua tau yog tsim tawm los ntawm hom tshwj xeeb ntawm voltage-gated ion channels embedded nyob rau hauv lub cell lub plasma membrane. Qhov no tom qab ntawd ua rau ntau txoj kev qhib, ua kom muaj hluav taws xob ntau dua hla cov cell membrane thiab lwm yam.
Raws li txoj cai, yuav ua li cas muaj peev xwm tsim tau?
Kev ua muaj peev xwm tshwm sim thaum sib txawv ions hla lub neuron membrane. Ib qho kev txhawb nqa ua ntej ua rau sodium channel qhib. Vim tias muaj ntau ntau sodium ions nyob rau sab nraud, thiab sab hauv ntawm cov neuron yog qhov tsis zoo rau sab nraud, sodium ions maj nrawm rau hauv cov neuron.
Tsis tas li ntawd, yuav ua li cas thiaj li muaj peev xwm ua kom cov membrane so? Qhov tsis zoo so membrane muaj peev xwm yog tsim thiab tswj los ntawm kev nce cov concentration ntawm cations sab nraum lub cell (nyob rau hauv lub extracellular kua) txheeb ze rau hauv lub cell (nyob rau hauv lub cytoplasm). Cov kev ua ntawm sodium poov tshuaj twj tso kua mis pab tswj lub so peev xwm , ib zaug tsim tawm.
Ib sab ntawm qhov no, dab tsi yog 4 kauj ruam ntawm kev ua tau zoo?
Ib qho kev muaj peev xwm ua tau tshwm sim los ntawm qhov pib los yog suprathreshold stimuli raws li neuron. Nws muaj plaub theem; hypopolarization, depolarization , overshoot, thiab repolarization . Ib qho kev txiav txim muaj peev xwm nthuav tawm raws cov cell membrane ntawm ib qho axon kom txog thaum nws mus txog lub davhlau ya nyob twg khawm.
Qhov twg yog qhov kev txiav txim muaj peev xwm pib tsim?
Cov ntsiab lus hauv cov txheej no (15) Qhov twg hauv cov neuron yog ib qho kev ua tej zaum pib generated ? Axon roob. cheeb tsam no (thawj ib feem ntawm lub axon) tau txais cov cim hauv zos (qib qhov muaj peev xwm) los ntawm soma thiab dendrites thiab muaj qhov siab ntawm cov hluav taws xob-gated Na + channels.
Pom zoo:
Yuav ua li cas so membrane muaj peev xwm tsim thiab khaws cia?
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Yuav ua li cas koj muab tau elastic muaj peev xwm zog?
Elastic muaj peev xwm lub zog yog lub zog muaj peev xwm khaws cia los ntawm ncab lossis compressing ib qho khoom elastic los ntawm lwm lub zog xws li ncab ntawm lub caij nplooj ntoos hlav. Nws yog sib npaug rau txoj haujlwm ua kom ncab lub caij nplooj ntoos hlav uas nyob ntawm lub caij nplooj ntoos hlav tas li k thiab qhov kev ncua deb
Dab tsi yog qhov txawv ntawm electrostatic muaj peev xwm thiab electrostatic muaj peev xwm zog?
Tsis muaj qhov sib txawv ntawm electrostatic potentialenergy thiab hluav taws xob (al) muaj peev xwm zog. Lub peev xwm hluav taws xob ntawm ib qho taw tes yog kev ua haujlwm los ntawm lwm qhov kev quab yuam hauv kev txav chav tsev zoo los ntawm ib qho arbitrarilychosen xoom ntawm lub peev xwm (feem ntau infinity) mus rau lub ntsiab lus
Puas muaj peev xwm hluav taws xob thiab lub zog muaj peev xwm tib yam Vim li cas lossis vim li cas ho tsis?
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Puas muaj peev xwm equilibrium zoo ib yam li so muaj peev xwm?
Qhov sib txawv ntawm daim nyias nyias muaj peev xwm thiab qhov muaj peev xwm sib npaug (-142 mV) sawv cev rau lub zog hluav taws xob hluav taws xob uas tsav Na + mus rau hauv lub xovtooj ntawm lub peev xwm so membrane. Thaum so, txawm li cas los xij, qhov permeability ntawm daim nyias nyias mus rau Na + tsawg heev kom tsuas yog me me Na + xau rau hauv lub cell