Hanganga me te Mahi o te Myocardium
Ko te uaua o te ngākau, e mōhiotia whānuitia ana ko te uaua o te ngākau, he mahi nui tāna ki te hauora o te ngākau, ā, he mea nui te mārama ki tōna hanganga me tana mahi hei mārama ki te mahi a te ngākau me te pupuri i te ora. Mā tēnei whakamātautau whānui ka hurahia ngā taipitopito uaua o te hanganga o te ngākau me ōna mahi ā-tinana, e whakaatu ana i tōna hiranga ki te pūnaha tohanga toto.
Hanganga Ā-tinana o te Myocardium
Te Hanganga Pūtau
Ko te myocardium te mea nui i titoa e ngā pūtau uaua motuhake e mōhiotia ana ko ngā cardiomyocytes. He ahurei te hanganga me te mahi o ēnei pūtau ki te whakataurite ki ētahi atu pūtau uaua o te tinana. Ko ngā cardiomyocytes te mea e kitea ai ngā rārangi – he rārangi mārama me ngā rārangi pōuri o ngā miro pūmua whakawhāiti – e kitea ana i raro i te karu hiko. Ko tēnei āhua rārangi nā te whakaritenga whakarite o ngā miro actin me myosin e āwhina ana i te whakawhāiti.
Ngā Kōpae Whakauru
Ko tētahi o ngā āhuatanga matua o ngā cardiomyocytes ko te noho mai o ngā kōpae kua whakapūmautia. He hononga matatini ēnei hanganga e hono ana i ngā cardiomyocytes takitahi, e āhei ai te kiko ki te mahi hei wāhanga kotahi. Kei roto i ngā kōpae kua whakapūmautia ngā desmosomes, e whakarato ana i te kaha ā-ringa mā te piri tahi i ngā pūtau, me ngā hononga āputa, e āhei ai te tuku tere o ngā tohu hiko puta noa i te myocardium. He mea nui tēnei mahi tahi mō te kaha o te ngākau ki te pupuhi toto pai.
Ngā Papa o te Pakitara o te Ngākau
E toru ngā paparanga matua o te pakitara o te ngākau: te epicardium, te myocardium, me te endocardium.
1. Epicardium: Koinei te paparanga o waho rawa o te ngākau, he kiko honohono me te ngako te nuinga. He paparanga tiaki tēnei, ā, he maha ngā wā kei roto ngā uaua toto e whāngai ana ki te uaua o te ngākau.
2. Myocardium: Ko te paparanga matotoru o waenganui te kiko uaua e whai kawenga ana mō ngā whakahekenga. Koinei te paparanga tino kaha, tino kaha hoki o te pakitara o te ngākau.
3. Endocardium: Ko tēnei paparanga o roto rawa e whakarārangi ana i ngā rūma o te ngākau, e kapi ana hoki i ngā takirere ngākau. He mea tito mai i ngā pūtau endothelial e whakarato ana i te mata maeneene mō te rere o te toto, ā, e whai wāhi ana ki te whakaiti i te mōrearea o te thrombosis.
Te Mahi a te Myocardium
Pūnaha Arataki me te Mahi Hiko
Ko te mahi matua a te uaua ngākau he whakahaere i te mahi pupuhi o te ngākau, e tutukihia ana mā te pūnaha kawe hiko tino taunga e tīmata ana, e hora ana hoki i ngā hikohiko. Ko ngā wāhanga matua o te pūnaha kawe hiko ko:
1. Pūnga Sinoatrial (SA): E mōhiotia ana ko te kaiwhakaoho manawa tūturu o te ngākau, kei te atrium matau te pūnga SA, ā, ka tīmata i ngā hiko e whakatakoto ana i te tere o te tere o te ngākau.
2. Pūnga Atrioventricular (AV): Kei te hononga i waenga i te atria me ngā ventricles, ka whiwhi te pūnga AV i ngā nekehanga mai i te pūnga SA, ā, ka whakaroa i te manawa kia pai ai te whakahekenga o te atria i mua i ngā ventricles.
3. Paihere o His: Ka tukuna e tēnei ara ngā nekehanga mai i te pūnga AV ki ngā ventricles mā roto i ngā peka paihere maui me matau.
4. Ngā muka Purkinje: Ka tohatohahia e ēnei muka ngā hiko puta noa i ngā ventricles, kia mōhio ai ka tīmata te whakahekenga o te uaua ngākau i te tihi ka neke ake ki te turanga, ka panaia te toto.
Mahi Whakakōpiri
Ko te mahi whakakōpiri o te uaua ngākau e ārahihia ana e te tikanga miro reti, e uru ana ki te taunekeneke i waenga i ngā miro actin me te myosin i roto i ngā cardiomyocytes. Ko te tukanga whakakōpiri (systole) me te whakangā (diastole) e whakahaeretia ana e te rerenga me te putanga o ngā iona konupūmā ki roto i ngā pūtau. I te wā systole, ka herea ngā iona konupūmā ki te troponin, ka puta he huringa āhua e āhei ai te myosin ki te here ki te actin me te whakaputa kaha. I te wā diastole, ka kaha te pupuhi i ngā iona konupūmā ki waho o ngā pūtau, ka arahi ki te whakangā.
Te Tukunga Toto
He tino kaha te pākia o te uaua ngākau ki ngā matūkai, ā, me nui te toto e hiahiatia ana hei pupuri i tana mahi. Ko ngā uaua ngākau, e peka mai ana i te aorta, ka tuku toto whai hāora ki te uaua ngākau. Ka uru ēnei uaua me ō rātou manga ki roto i te uaua ngākau, ka tuku toto ki ngā rohe rerekē o te uaua ngākau. Ka kohia te toto uaua mai i te uaua ngākau e ngā uaua ngākau, ka huihui hei hanga i te sinus ngākau e rere ana ki te atrium matau.
Te Whai Hua o te Mīhini
Ko te kaha o te ngākau ki te pupuhi toto i runga i te pai he tohu i te hanganga o te uaua ngākau me tōna urutau ki ngā hiahia hemodynamic o te tinana. I ia wā o te pao o te ngakau, me whakaputa e ngā ventricles te pēhanga e tika ana hei wikitoria i te ātete i roto i ngā tohanga toto pūnaha me ngā tohanga toto pūkahukahu. Mā te whakahekenga ōrite o te uaua ngākau ka taea e te ngākau te whakarerekē i tana putanga kia tutuki ai ngā hiahia rerekē o te tinana, pērā i te wā e whakakorikori tinana ana, e ahotea ana rānei.
Te Whakarerekētanga me te Whakahoutanga
He tino kaha te urutau o te uaua ngākau. Hei whakautu ki te pikinga o te mahi, pērā i ngā kaitākaro manawanui, ka piki haere te uaua ngākau, arā, ka nui haere te rahi o ngā cardiomyocytes, ka kaha ake te ngākau. I tua atu, i roto i ngā āhuatanga mate pēnei i te toto toto tiketike, te ngoikore rānei o te ngākau, ka rerekē pea te urutau o te uaua ngākau, e tohuhia ana e te nui rawa o te fibrosis, te whakarerekētanga o te hanganga pūtau, me te ngoikore o te kaha o te mahi whakapūmau.
Te Mate o te Ngākau
He mea nui te mārama ki te pathology myocardial hei aro atu ki ngā mate manawa. Ko ngā āhuatanga pēnei i te myocardial infarction (whakaekenga manawa) ka puta mai i te haukotinga o te rere o te toto ki te myocardium, ka arahi ki te mate pūtau me te ngoikore o te mahi a te manawa. Ko ngā āhuatanga mau tonu pēnei i te cardiomyopathies, ina he rerekē te hanganga me te mahi a te myocardium, e whakaatu ana hoki i te hiranga o te pupuri i te hauora o te myocardium.
Opaniraa
He mea nui te hanganga me te mahi a te uaua ngākau ki te mahi a te ngākau ki te pupuri i te taurite o te tohanga toto me te hauora whānui. Ko tōna hanganga pūtau ahurei, te tikanga whakahekenga tukutahi, me tōna āheinga ki te urutau ki ngā āhuatanga rerekē o te tinana e whakaatu ana i tōna hiranga. Kei te haere tonu te rangahau ki te mahi a te uaua ngākau ki te whakaputa māramatanga ki ngā āhuatanga noa o te tinana me ngā āhuatanga mate, e tuku ana i ngā huarahi pea mō ngā wawaotanga rongoā i roto i ngā mate ngākau. He mea whakamiharo te uaua ngākau o te hangarau koiora, he mea nui ki te mauri o te ora.
