Lo mshini imisipha. Imisebenzi kanye izakhiwo kwemisipha lwamathambo

Imisipha - Lena inqubo eyinkimbinkimbi ehlanganisa eziningi izigaba. Izingxenye ezisemqoka lapha myosin, actin, troponin, tropomyosin futhi actomyosin, ne-calcium ion futhi izakhi ahlinzeke imisipha amandla. Cabangela izinhlobo futhi izindlela imisipha. Masitadishe which they zenziwa futhi izinyathelo ezidingekile ukuze inqubo cyclical.

imisipha

Imisipha ehlangana ngamaqembu, iyiphi indlela efanayo imisipha. Ngokufanayo bahlukene zibe 3 izinhlobo:

• imisipha striated umzimba;
• imisipha striated we Atria futhi ventricles wenhliziyo;
• bushelelezi imisipha izitho, imithambo yegazi kanye isikhumba.

imisipha Striated bayingxenye uhlelo zemisipha, yingxenye ke, ngoba ngaphezu kwabo, lokhu kuhlanganisa imisipha, nemisipha, amathambo. Lapho kwetfula mshini imisipha, imisebenzi elandelayo kanye nemisebenzi:

• uhamba emzimbeni;
• izitho zomzimba sishukumiseleka isihlobo komunye nomunye;
• umzimba kusekelwa esikhaleni;
• ukushisa ekhiqizwa;
• cortex ivuswe ngu afferent emasimini elungele ukwamukela okufundayo kwemisipha.

Kwemisipha bushelelezi yilesi:

• motor apharathasi kwezitho zangaphakathi, okubandakanya kwesihlahla bronchial, amaphaphu tube wokugaya ukudla;
• i-lymph kanye kwegazi izinhlelo;
• uhlelo izitho urogenital.

izakhiwo bokuphila

Njengazo zonke ezilwaneni ezinomgogodla ezinamehlo emzimbeni womuntu kukhona izakhiwo ezintathu ebaluleke kakhulu lwamathambo imisipha Imicu yotshani yilezi:

• contractility - ukunciphisa nokushintsha kwamandla lapho yavusa;
• conductivity - ukunyakaza umthamo kulo lonke fibre;
• excitability - ephendula umfutho ngokushintsha ulwelwesi zivele futhi ion permeability.

Imisipha sijabulile futhi baqala ukunqabela ngu ezinzwa amaza ivela isikhungo. Kodwa ngaphansi kwezimo yokufakelwa usebenzisa ukushukuma kagesi. Imisipha Ungabese wacasuka ngqo (ukushukuma ngqo) noma ngokusebenzisa imisipha emsipheni innervating (ukushukuma ngokungaqondile).

izinhlobo ukusikeka

Lo mshini ukusikwa kwemisipha kusho ukuguqulwa amakhemikhali namandla ku umsebenzi lokukhanda. Le nqubo lingalinganiswa Ucwaningo ne frog: ithole imisipha umthwalo wakhe isisindo ongaphakeme, bese obulimaza electroimpulses ukukhanya. Ukwehla, lapho imisipha iba mfushane, ngokuthi isotonic. kokunciphisa kwenzeka ukusikwa lapho icwecwe eliqophayo. Imisipha ungavumeli ukuthuthukiswa amandla kwemisipha mfushane. Esinye isimiso esikwazi auksotonichesky of imisipha kuhilela izimo zokucindezeleka okukhulu lapho imisipha sifushanise indlela incane khona, futhi amandla ukufinyelela esiphezulu.

Sakhiwo innervation kwemisipha lwamathambo

I striated imisipha lwamathambo kuhlanganisa ezihlukahlukene zesivikelo sezicubu zezinzwa futhi eqondiswa imisipha. Kwezinye Imicu yotshani imisipha ahlelwe parallel eksisi eside, kanti kwabanye abayikho ukubukwa etshekile, kokuba exhunywe emaphakathi umsipha tyazhu futhi pinnate hlobo.

Isici esiyinhloko fiber kuyinto mass sarcoplasm sendikimba esihle - myofibrils. Ziyakwazi izindawo egqamile futhi kumnyama nese komunye nomunye, kanti le micu eduze striated kukhona ezishaywayo - e cross-section. Lokhu kuphumela cross-nisishiye siboshwé ngebhande emhlabeni le micu kwemisipha.

Sarcomere kuyinto amadiski eziyinkimbinkimbi, amnyama futhi ezimbili ukukhanya, futhi delimited imigqa ezimise Z-. Sarcomeres - kungaphefumuli contractile kwemisipha. It kuvela ukuthi fibre contractile imisipha liqukethe:

• contractile apharathasi (myofibrils uhlelo);
• ama-apharathasi trophic nge mitochondria, Golgi eziyinkimbinkimbi futhi ebuthaka reticulum endoplasmic ;
• idivayisi ulwelwesi;
• inkomba apharathasi;
• ama-apharathasi sezinzwa.

Imisipha fibre ihlukaniswe yaba izingxenye 5 akhiwe nemisebenzi, futhi iyingxenye ebalulekile ijwabu kwemisipha.

innervation

Le nqubo e striated imisipha Imicu yotshani ezalethwa yezinzwa, okungukuthi axons ka Izinzwa we umgogodla nentambo ubuchopho stem. Omunye motoneuron innervate Imicu yotshani eziningana kwemisipha. Inxanxathela nge neuromotor motoneuron futhi innervated imisipha Imicu yotshani ngokuthi (HME) noma iyunithi motor (MU). Inombolo emaphakathi imicu, okuyinto innervates a motoneuron, ephawula DE imisipha, ngokuthi okuhambisanayo innervation kwabantu. Ngalo mbuzo wesibili ngobukhulu bemisipha, lapho ukunyakaza amancane "nomzimba omncane" (amehlo, iminwe, ulimi). Inani layo incane, kunalokho, e imisipha nge "indawo" ezinyakazayo (isib esifubeni).

Innervation kungaba olulodwa futhi amaningi. Esimweni sokuqala-ke yaqaphela compact motor eziyimpumelelo. Ngokuvamile kuba ejwayelekile ezinkulu Izinzwa. Imicu yotshani Muscle (ngokuthi kuleli cala, ngokomzimba, noma okusheshayo) odala PD (isinyathelo nekhono) ezisebenza kubo.

innervation Multiple kwenzeka, isibonelo, in the imisipha iso zangaphandle. Lokhu akuyona engaba senzo elakhiwe, kusukela ulwelwesi elingenaziteshi electroexcitability sodium. Basuke yasakazwa kulo lonke fibre depolarization we eziyimpumelelo izinhlaka zokuxhumana zobuchopho. Lokhu kuyadingeka ukuze kusebenze mshini imisipha. Inqubo lapha hhayi njengawe esimweni sokuqala. Ngakho, ubizwa ngokuthi kancane.

Isakhiwo myofibrils

ucwaningo fibre imisipha kwenziwe namuhla ngesisekelo-X-ray umumo womsebenzi, electron microscopy, nezindlela histochemical.

Kulinganiselwa ukuthi e myofibril ngamunye, ububanzi okuyinto 1 Micron, kuhlanganisa cishe 2,500 protofibrils, isb side polymerized molecule amaprotheni (actin futhi myosin). protofibrils Actin myosin kabili ohlabayo. Lapho esephumule, le misipha zitholakala kangangokuthi izihloko actin intambo ukungena izikhala phakathi protofibrils myosin.

A strip ewumngcingo zokukhanya disk A ukhululekile actin kwayo. Ulwelwesi Z ubenza ndawonye.

On myosin sesigcilikisha babe ziboya transverse kuze 20 NM, ku amakhanda okuyinto mayelana 150 myosin molecule. Base behamba biopolyarno, futhi ikhanda myosinic ngamunye uxhuma intambo actin. Lapho kukhona ukucindezeleka ku kwayo ka actin izikhungo myosin, actin intambo iseduze maphakathi sarcomere. Ekupheleni kwayo myosin ukufinyelela Z. umugqa Bese bethatha yonke sarcomere, futhi actin aphakathi kwazo. Ngesikhathi esifanayo lapho ngishayela obuphelele kuyehla, futhi ekugcineni iphele ngokuphelele, kanye nalokho Z umugqa kuba mkhulu.

Ngakho, ngokuvumelana imfundiso yokuziphendukela ezihambayo lokuluhlaza, ngenxa yobude ukuncipha kwezintambo zesivikelo sesifuba kwemisipha. Imfundiso, ngokuthi "igiya", yasungulwa ngu Huxley futhi Hanson phakathi kwekhulu lamashumi amabili.

Mechanism kwemisipha fibre ukusikwa

Imfundiso eyinhloko ukuthi akukho intambo (myosin futhi actin) ziyakufinyezwa. Ubude yabo uhlala ukungezwani ingashintshiwe futhi imisipha. Kodwa izinyanda sesigcilikisha mncane, ilele, hamba phakathi kwayo aminyene, kunciphe degree of kweqa, ngakho kukhona ukwehliswa.

Mshini yamangqamuzana ukusikwa kwemisipha kanje ngokuslayidisa actin kwayo. Myosin ikhanda exhunywe protofibrils nge actin. Nge emithambekeni zabo kukhona beya, ukuhambisa actin intambo kuya maphakathi sarcomere. Ngenxa inhlangano okuguquguqukayo ka myosin molecule nhlangothi zombili kwayo, izimo noma ngokuhambisa ka actin sesigcilikisha bacondze etindzaweni letehlukene.

Lapho muscle myosin ikhanda asuka sesigcilikisha actin. Ngomqondo ukushelela lula ekhululekile imisipha ukungezwani ekumelaneni ingasaphathwa. Ngakho-ke, basuke zibukele yinde.

izinyathelo zokunciphisa

Lo mshini ukusikwa kwemisipha kungenziwa kafushane luhlukaniswe izigaba ezilandelayo:

1. Imisipha fibre ziyashukumiseka lapho i engaba senzo enikeziwe kusukela Izinzwa we synapse.
2. Neqiniso senzo elakhiwe phezu ulwelwesi we fibre imisipha, bese isakazekela myofibrils.
3. Kufezeke pair electromechanical emele ukuguqulwa kagesi ku mechanical PD beya. Lokhu ngempela kuhilela calcium ion.

calcium ion

Ukuze uthole ukuqonda kangcono inqubo fibre kusebenze i-calcium ion esivumelana cabanga isakhiwo intambo actin. Ubude bayo 1 Micron, ukujiya - 5 kuya ku-7 NM. Lena pair sendikimba nesisontekile, okuyinto abafana monomer actin. Cishe zonke nm 40 nazi eyindilinga troponin molecule futhi phakathi amaketanga - tropomiozinovye.

Lapho i-calcium ion bengekho, myofibrils ie uphumule eside molecule tropomiozinovye ukuvimba ukunamathela actin ngamaketanga futhi myosin amabhuloho. Kodwa uma ocushiwe calcium ion tropomiozinovye molecule ukucwila ezindaweni ezijulile futhi evulekile.

Khona-ke amabhuloho myosin anamekwe actin sesigcilikisha kanye ezidabula ATP futhi eba namandla kwemisipha. Lokhu kungenzeka ngenxa umthelela calcium troponin. Kulesi-molecule mithandazo zikhubazekile, kanjalo baphokophelele tropomyosin.

Lapho imisipha ekhululekile, kungenxa 1 igremu isisindo ezimanzi iqukethe kuka 1 mmol calcium. Calcium nosawoti ziqhelile futhi ekhethekile isitoreji izindawo. Kungenjalo, imisipha njalo kunqatshelwe.

calcium imali kanje. Ezindaweni ezahlukene diaphragm imisipha cell angaphakathi fibre ayimibhobho lapho kukhona uxhumano imvelo ngaphandle amaseli. Kuyinto simiso tubules transverse. A uhlelo perpendicular imikhawulo longitudinal zazo - vesicles (ukugcina) amathangi ahlelwe iseduze uhlelo transverse diaphragms. Ndawonye etholwe triad. Kwakungenxa izitsha eziyisikhombisa agcinwe i-calcium.

Njengoba PD isakazwa esitokisini, futhi kukhona conjugation electromechanical. Excitation lingena fibre sihamba ibe longitudinal uhlelo ukukhishwa calcium. Kanjalo indlela yokunciphisa wenziwa imisipha zesivikelo sesifuba.

3 inqubo nge ATP

Esikhathini nokuxhumana kokubili imicu ebukhoneni calcium ion indima esiningi ATP. Lapho kwetfula mshini imisipha ye imisipha yohlaka, amandla ATP isetshenziselwa:

• ukusebenza sodium ne-potassium futha okuyinto igcina okuhlushwa njalo ion;
• lezi izinto ezinhlangothini ezahlukene ulwelwesi;
• ngokuhambisa sesigcilikisha kunciphisa myofibrils;
• Jobe calcium futha isinyathelo uphumule.

ATP kuyinto ulwelwesi cell, kwayo ka myosin futhi sarcoplasmic reticulum ulwelwesi. Enzyme sokudiliza bese kulahlwa konke eyayakhiwe myosin.

ukusetshenziswa ATP

Kuyaziwa ukuthi myosin amakhanda uxhumana actin futhi iqukethe izinto ngoba cleavage ATP. Kugcine actin yasebenza futhi myosin ebukhoneni magnesium ion. Ngakho-ke ama-enzyme cleavage senzeka lapho enamathiselwe actin myosin ikhanda. Kukhula cross-amabhuloho, ijubane eqhekeza kuyoba ephakeme.

ATP indlela

Ngemva kokuphothulwa ukuhamba AFL-molecule inikeza amandla zokwehlukanisa ukusabela ehilelekile actin futhi myosin. Myosin ikhanda ahlukaniswe, ATP is wajinge wanamatsela ukuba phosphate futhi Adp. Ukuphela entsha ixhunyiwe ATP-molecule futhi umjikelezo iyaqala. Njalo is mshini imisipha nokungcebeleka ezingeni yamangqamuzana ezinto eziphilayo.

Umsebenzi wesi--amabhuloho izothatha kuphela njengoba nje hydrolysis ATP kwenzeka. Uma ukuvimba amabhuloho enzyme ngeke inamithiselwe futhi.

Lapho kuqala ukufa umzimba ezingeni ATP kumaseli uwela namabhuloho izohlala stably eqondiswa intambo actin. Ngakho kukhona esigabeni of okukhulu mortis.

ATP resynthesis

Resynthesis ezingase zithathwe ngezindlela ezimbili.

Ngu ukudluliselwa enzymatic of iqembu phosphate kusukela creatine phosphate ukuze Adp. Njengoba amasheya creatine kuseli okuningi ATP resynthesis washeshe kakhulu. Ngesikhathi esifanayo, i-namachibi of pyruvic acid acidosis acid resynthesis kuyoba kancane.

ATP futhi CP inganyamalala ngokuphelele uma resynthesis kuyinto ubuthi eziphukile. Khona-ke i-calcium futha stop zokusebenza, okuholela imisipha is itjhuguluko engekhe yalungiseka encishisiwe (ie ukuza contracture). Ngakho, uma behlukaniswa mshini ukusikwa kwemisipha.

inqubo zomzimba

Kafushane, siphawula ukuthi zokunciphisa imisipha Imicu yotshani mfushane ngamunye myofibrils sarcomeres. Kwayo ka myosin (obukhulu) kanye actin (mncane) imikhawulo exhunywe esimweni esikhululekile. Kodwa ukuqala ngokuhambisa ukunyakaza ngomunye nomunye lapho lwenteke mshini imisipha. Physiology (kafushane) uchaza inqubo lapho myosin ukuthonywa ikhishwe amandla awadingayo ukuguqula ATP ukuze Adp. Ngakho umsebenzi myosin eziyojatshulelwa kuphela uma okuqukethwe okwanele-calcium ion buthelela ku reticulum sarcoplasmic.