Txhua yam kev ntxhov siab ua haujlwm tau zoo vim muaj kev hloov pauv ntawm cov theem ntawm so thiab excitability. Tsis ua hauj lwm nyob rau hauv lub polarization system cuam tshuam cov hluav taws xob conductivity ntawm cov fibers. Tab sis dhau li ntawm cov paj hlwb, muaj lwm cov ntaub so ntswg uas txaus siab - endocrine thiab cov leeg.
Tab sis peb yuav xav txog cov yam ntxwv ntawm cov ntaub so ntswg conductive, thiab siv cov piv txwv ntawm cov txheej txheem ntawm excitation ntawm cov organic hlwb, peb yuav qhia txog qhov tseem ceeb ntawm theem tseem ceeb ntawm depolarization. Lub physiology ntawm lub paj hlwb muaj feem cuam tshuam nrog cov ntsuas hluav taws xob sab hauv thiab sab nraud ntawm cov paj hlwb.
Yog tias ib qho hluav taws xob txuas nrog lub plhaub sab nraud ntawm axon, thiab lwm qhov rau nws sab hauv, ces muaj qhov sib txawv. Kev ua hluav taws xob ntawm cov hlab ntsha txoj hauv kev yog raws li qhov sib txawv no.
Qhov muaj peev xwm so thiab kev ua haujlwm yog dab tsi?
Txhua lub hlwb ntawm lub paj hlwb yog polarized, uas yog, lawv muaj cov hluav taws xob sib txawv sab hauv thiab sab nraud ntawm daim nyias nyias tshwj xeeb. Lub paj hlwb yeej ib txwmNws cov lipoprotein membrane, uas muaj kev ua haujlwm ntawm bioelectric insulator. Ua tsaug rau cov membranes, lub peev xwm so hauv cell yog tsim, uas yog tsim nyog rau kev ua kom tom ntej.
Lub peev xwm so tau tswj hwm los ntawm kev hloov pauv ntawm ions. Kev tso tawm ntawm cov poov tshuaj ions thiab nkag mus ntawm cov tshuaj chlorine ua rau kom cov membrane so lub peev xwm.
Kev ua tau muaj peev xwm sib sau ua ke nyob rau theem ntawm depolarization, uas yog, qhov nce ntawm cov nqi hluav taws xob.
Cov theem ntawm qhov ua tau zoo. Physiology
Yog li, depolarization hauv physiology yog qhov txo qis hauv daim nyias nyias. Depolarization yog lub hauv paus rau qhov tshwm sim ntawm excitability, uas yog, lub peev xwm ua rau lub paj hlwb. Thaum ib qho tseem ceeb ntawm depolarization mus txog, tsis muaj, txawm tias muaj zog stimulus, muaj peev xwm ua rau muaj kev cuam tshuam hauv paj hlwb. Nyob rau tib lub sijhawm, muaj ntau cov sodium hauv axon.
Tam sim tom qab theem no, theem ntawm kev txheeb ze excitability ua raws. Cov lus teb yog twb ua tau, tab sis tsuas yog mus rau lub zog stimulus teeb liab. Kev txheeb ze excitability maj mam dhau mus rau theem ntawm kev tsa nto. Kev tsa nto yog dab tsi? Nov yog qhov kawg ntawm cov ntaub so ntswg excitability.
Txhua lub sijhawm no cov kev ua haujlwm sodium tau raug kaw. Thiab lawv qhov qhib yuav tshwm sim tsuas yog thaum lub paj hlwb tawm. Repolarization yog xav tau los kho cov nqi tsis zoo hauv cov fiber ntau.
qib tseem ceeb ntawm kev depolarization (CDL) txhais li cas?
Yog li, kev txaus siab yog nyob rau hauv physiologylub peev xwm ntawm lub cell los yog cov ntaub so ntswg los teb rau ib tug stimulus thiab tsim ib co yam ntawm impulse. Raws li peb pom, cov hlwb xav tau ib qho nqi - polarization - ua haujlwm. Qhov nce nqi ntawm rho tawm mus ntxiv yog hu ua depolarization.
Tom qab depolarization, ib txwm muaj repolarization. Tus nqi sab hauv tom qab lub excitation theem yuav tsum tsis zoo dua kom lub cell tuaj yeem npaj rau cov tshuaj tiv thaiv tom ntej.
Thaum qhov kev nyeem ntawv voltmeter tau kho ntawm 80, qhov no yog theem so. Nws tshwm sim tom qab qhov kawg ntawm repolarization, thiab yog tias lub cuab yeej qhia tau tias muaj txiaj ntsig zoo (ntau dua 0), ces qhov rov qab repolarization theem yog nce mus txog qib siab tshaj plaws - theem tseem ceeb ntawm depolarization.
Impulses kis los ntawm paj hlwb mus rau cov leeg li cas?
Hluav taws xob impulses uas tau tshwm sim thaum lub sij hawm excitation ntawm daim nyias nyias yog kis raws cov hlab ntsha fibers ntawm kev kub ceev. Qhov ceev ntawm lub teeb liab tau piav qhia los ntawm cov qauv ntawm axon. Lub axon yog ib feem ntawm lub hnab ntim khoom. Thiab ntawm thaj chaw myelinated yog cov ntawm Ranvier.
Ua tsaug rau qhov kev npaj ntawm cov paj hlwb, cov nqi zoo hloov pauv nrog qhov tsis zoo, thiab cov depolarization tam sim no nthuav tawm yuav luag ib txhij nyob rau tag nrho qhov ntev ntawm axon. Lub teeb liab contraction ncav cuag cov leeg hauv ib feem ntawm ib pliag. Xws li qhov taw qhia raws li theem tseem ceeb ntawm daim nyias nyias depolarization txhais tau hais tias lub cim ntawm qhov ua tau zoo tshaj plaws tau mus txog. Tom qab cov leeg nqaij contraction, repolarization pib raws tag nrho axon.
Yuav ua li casThaum lub sij hawm depolarization?
qhov ntsuas li cas raws li qib tseem ceeb ntawm depolarization txhais tau li cas? Hauv physiology, qhov no txhais tau hais tias cov paj hlwb twb tau npaj ua haujlwm. Kev ua haujlwm raug ntawm tag nrho lub cev yog nyob ntawm qhov qub, hloov raws sijhawm ntawm cov theem ntawm qhov ua tau zoo.
Qib tseem ceeb (CLL) yog kwv yees li 40–50 Mv. Thaum lub sij hawm no, hluav taws xob teb nyob ib ncig ntawm lub membrane txo. Qhov degree ntawm polarization ncaj qha nyob ntawm seb muaj pes tsawg sodium channels ntawm tes qhib. Lub xovtooj ntawm lub sijhawm no tseem tsis tau npaj rau cov lus teb, tab sis sau cov peev txheej hluav taws xob. Lub sijhawm no yog hu ua absolute refractoriness. Lub sijhawm tsuas yog 0.004 s hauv paj hlwb, thiab hauv cardiomyocytes - 0.004 s.
Tom qab dhau theem tseem ceeb ntawm depolarization, super-excitability tau teeb tsa. Cov paj hlwb tuaj yeem teb tau txawm tias qhov kev txiav txim ntawm qhov kev txhawb nqa subthreshold, uas yog, qhov cuam tshuam tsis zoo ntawm ib puag ncig.
Kev ua haujlwm ntawm sodium thiab potassium channels
Yog li, tus neeg koom nrog tseem ceeb hauv cov txheej txheem ntawm depolarization thiab repolarization yog cov protein ion channel. Cia peb kawm seb lub tswvyim no txhais li cas. Ion channels yog cov protein macromolecules nyob rau hauv lub plasma membrane. Thaum lawv qhib, inorganic ions tuaj yeem dhau los ntawm lawv. Protein channels muaj cov lim dej. Tsuas yog sodium kis tau los ntawm cov sodium duct, tsuas yog cov khoom no dhau los ntawm cov poov tshuaj duct.
Cov kab hluav taws xob tswj hwm no muaj ob lub rooj vag: ib qho yog ua kom muaj zog, muaj peev xwm dhau ions, lwm qhovkev tsis ua haujlwm. Thaum lub sij hawm thaum lub sij hawm so daim nyias nyias yog -90 mV, lub rooj vag kaw, tab sis thaum depolarization pib, sodium raws maj mam qhib. Kev nce hauv qhov muaj peev xwm ua rau muaj qhov kaw ntawm cov kav dej.
Qhov tseem ceeb uas cuam tshuam rau kev ua kom cov channel yog excitability ntawm cell membrane. Raws li kev cuam tshuam ntawm hluav taws xob excitability, 2 hom ion receptors tau pib:
- pib qhov kev txiav txim ntawm ligand receptors - rau chemodependent raws;
- hluav taws xob teeb liab thov rau hluav taws xob ua raws.
Thaum qhov tseem ceeb ntawm cov cell membrane depolarization tau mus txog, cov receptors muab lub teeb liab tias tag nrho cov sodium channel yuav tsum raug kaw, thiab cov kab poov tshuaj pib qhib.
Sodium Potassium Pump
Cov txheej txheem ntawm kev hloov pauv qhov kev tawm dag zog txhua qhov chaw tshwm sim vim qhov hluav taws xob polarization tau ua los ntawm kev txav ntawm sodium thiab potassium ions. Kev txav ntawm cov ntsiab lus tshwm sim los ntawm lub hauv paus ntsiab lus ntawm kev thauj mus los ntawm ion active - 3 Na+ sab hauv thiab 2 K+ sab nraud. Qhov kev hloov pauv no yog hu ua lub twj tso kua mis sodium-potassium.
Depolarization ntawm cardiomyocytes. Phases of the heartbeat
Lub voj voog mob plawv kuj tseem cuam tshuam nrog hluav taws xob depolarization ntawm txoj hauv kev. Cov teeb liab cog lus ib txwm los ntawm SA hlwb nyob rau hauv txoj cai atrium thiab propagates raws Hiss txoj kev mus rau Torel thiab Bachmann bundles mus rau sab laug atrium. Cov txheej txheem sab xis thiab sab laug ntawm lub nra ntawm Hiss xa cov teeb liab mus rau lub ventricles ntawm lub plawv.
paj hlwb depolarize sai dua thiab nqa lub teeb liab vim muaj cov myelin sheath, tab sis cov leeg nqaij kuj maj mam depolarizes. Ntawd yog, lawv cov nqi hloov pauv ntawm qhov tsis zoo mus rau qhov zoo. Lub sijhawm no ntawm lub voj voog ntawm lub plawv yog hu ua diastole. Txhua lub hlwb ntawm no yog kev sib txuas thiab ua haujlwm ua ib qho nyuaj, txij li kev ua haujlwm ntawm lub siab yuav tsum tau sib koom ua ke ntau li ntau tau.
Thaum ib theem tseem ceeb ntawm depolarization ntawm phab ntsa ntawm sab xis thiab sab laug ventricles tshwm sim, lub zog tso tawm yog tsim - lub plawv cog lus. Tag nrho cov hlwb tom qab ntawd rov ua dua thiab npaj rau lwm qhov kev cog lus.
Kev nyuaj siab Verigo
Hauv xyoo 1889, ib qho tshwm sim hauv lub cev tau piav qhia, uas yog hu ua Verigo's catholic kev nyuaj siab. Cov theem tseem ceeb ntawm depolarization yog theem ntawm depolarization uas tag nrho cov sodium channel twb tsis ua haujlwm, thiab cov poov tshuaj raws ua haujlwm. Yog hais tias qhov degree ntawm tam sim no nce ntau dua, ces qhov excitability ntawm cov hlab ntsha fiber ntau yog txo. Thiab theem tseem ceeb ntawm depolarization nyob rau hauv qhov kev txiav txim ntawm stimuli mus tawm scale.
Lub sijhawm Verigo txoj kev nyuaj siab, qhov nrawm ntawm kev ua kom zoo siab txo qis, thiab, thaum kawg, tag nrho. Lub xovtooj ntawm tes pib hloov pauv los ntawm kev hloov cov haujlwm ua haujlwm.
Y
Adaptation mechanism
Nws tshwm sim tias nyob rau hauv qee qhov xwm txheej, qhov depolarizing tam sim no tsis hloov mus ntev. Qhov no yog tus yam ntxwv ntawm kev xav fibers. Qhov kev ncua sij hawm ntev zuj zus nyob rau hauv qhov tam sim no saum toj no tus qauv ntawm 50 mV ua rau muaj kev nce hauv qhov zaus ntawm cov hluav taws xob pulses.
Nyob rau hauv cov lus teb rau cov teeb liab no, lubconductivity ntawm poov tshuaj membrane. Cov kab qeeb qeeb tau qhib. Yog li ntawd, lub peev xwm ntawm cov paj hlwb rov ua cov lus teb tshwm sim. Qhov no hu ua paj hlwb adaptation.
Thaum hloov kho, hloov pauv ntau ntawm cov cim luv luv, cov hlwb pib sib sau thiab tso tawm ib lub peev xwm muaj zog. Thiab qhov sib txawv ntawm ob qhov kev tshwm sim tau nce.
