Graded Potential vs Action Potential
Tag nrho lub cev lub cev muaj peev xwm ua rau daim nyias nyias, feem ntau vim yog qhov tsis sib xws ntawm sodium, chloride, thiab potassium ions thiab kuj vim qhov sib txawv permeability ntawm cov plasma membrane rau cov ions. Qhov no daim nyias nyias muaj peev xwm ua rau muaj txiaj ntsig zoo thiab tsis zoo nyob rau hauv daim nyias nyias. Cov neurons thiab cov leeg hlwb yog ob hom hlwb tshwj xeeb uas tau tsim tshwj xeeb siv rau lub peev xwm membrane. Lawv tuaj yeem dhau mus ib ntus, hloov pauv sai hauv lawv cov peev txheej membrane vim qhov stimuli. Cov kev hloov no thaum kawg ua rau cov teeb liab hluav taws xob. Neurons siv cov teeb liab no kom tau txais, txheej txheem, pib, thiab xa cov lus thaum cov leeg nqaij siv lawv los pib kev cog lus. Muaj ob hom qauv ntawm hluav taws xob cov teeb liab, uas cov neurons siv los xa cov lus, uas yog, qib peev xwm thiab kev ua tau zoo.
Graded Potentials
Graded peev xwm yog qhov hloov pauv me me hauv cov peev txheej membrane uas tshwm sim hauv qib sib txawv lossis qib ntawm qhov loj lossis lub zog. Qhov muaj peev xwm muab qhab nia yog tshwm sim los ntawm kev ua kom cov chav kawm ntawm cov proteins hu ua 'gated ion channels' thiab tuaj yeem tsim los ntawm kev hnov qab lossis lub cev muaj zog thiab pib cov txheej txheem ntawm kev xa tawm. Lub gated ion channel xaiv tso cai tsuas yog qee yam ions kom nthuav tawm los ntawm nws. Thaum nws tso cai rau diffusing, nws qhib, thiab thaum nws tsis tso cai, nws raug kaw. Yog li ntawd, lub gated ion channel coj zoo li lub qhov rooj uas tuaj yeem qhib lossis kaw.
Tus nqi ntawm cov lus teb ion sib txawv nyob ntawm lub zog ntawm qhov kev txhawb nqa; yog li lub zog stimulus ua rau ntau ion channel qhib. Yog tias ntau cov ion channel qhib, ntau ions yuav kis thoob plaws hauv cov ntshav plasma, ua rau muaj kev hloov pauv loj dua hauv daim nyias nyias.
Action Potentials
Cov peev xwm ua tau yog luv luv, nrawm, hloov pauv loj hauv daim nyias nyias muaj peev xwm thiab tsim tawm hauv cov hlwb ua kom txaus siab (paj hlwb thiab cov leeg) thaum lub peev xwm so tau hloov pauv. Ib qho kev nqis tes ua muaj peev xwm tsuas yog ib feem me me ntawm tag nrho cov cell membrane uas txaus siab thiab nthuav tawm thoob plaws qhov seem ntawm cov cell membrane yam tsis muaj kev txo qis hauv lub zog ntawm lub teeb liab.
Thaum muaj peev xwm ua tau, lub peev xwm ntawm daim nyias nyias hloov mus. Thaum depolarization ncav cuag qhov pib muaj peev xwm, nws yuav ua rau muaj peev xwm ua tau. Lub peev xwm ua tau tshwm sim los ntawm chav kawm ntawm ion channel hu ua voltage -gated ion channels. Cov ion channel no muaj nyob rau hauv ob qho tib si neurons thiab cov leeg hlwb. Hauv cov neurons, ob qhov sib txawv voltage ion channel yog siv los tsim cov peev txheej, uas yog, voltage-gated Na+ channels thiab voltage-gated K+ cov channel. Cov channel no qhib thiab kaw hauv cov lus teb rau cov kev hloov pauv hauv cov peev txheej membrane, thiab lawv tswj cov dej ntws ntawm cov ions los ntawm kev xaiv kom lawv txav mus los ntawm lawv.
Qhov txawv ntawm Qib Peev Xwm thiab Kev Ua Tau Zoo yog dab tsi?
• Cov peev txheej ua haujlwm ua haujlwm raws li cov cim kev ncua deb thaum qhov muaj peev xwm muab qhab nia ua haujlwm luv luv.
• Cov peev txheej tau qhab nia yog qhov hloov pauv me me hauv cov peev txheej membrane uas tuaj yeem txhawb nqa lossis cuam tshuam ib leeg. Hauv qhov sib piv, qhov muaj peev xwm ua tau yog qhov loj (100 mV) hloov pauv hauv daim nyias nyias muaj peev xwm ua tau raws li kev ntseeg siab ntev-ntev teeb liab.
• Ua kom cov kab hluav taws xob gated ion ua rau muaj peev xwm muab qhab nia whereas qhov ua kom muaj zog ntawm cov kab hluav taws xob-gated ion ua rau muaj peev xwm ua tau.
• Net txav ntawm Na+, Cl–, lossis Ca2+ hla plasma membrane ua rau muaj peev xwm graded. Sequential txav ntawm Na+ rau hauv thiab K+ tawm ntawm lub xovtooj hla cov kab hluav taws xob-gated ua rau muaj peev xwm ua tau.
• Lub sijhawm ntawm qhov muaj peev xwm muab qhab nia sib txawv nrog lub sijhawm ntawm qhov tshwm sim tshwm sim lossis qhov kev txhawb nqa thaum lub sijhawm ua haujlwm muaj peev xwm tas li.
• Lub peev xwm ua tau tshwm sim hauv thaj tsam ntawm daim nyias nyias uas muaj ntau ntawm cov kab hluav taws xob-gated thaum lub peev xwm qib tshwm sim hauv thaj tsam ntawm daim nyias nyias tsim los teb rau qhov tshwm sim tshwm sim.
