Ngā Tauira Pātai e Matapaki ana i te Tukanga Impulse Io
He wāhanga nui o te pūnaha io te tukanga whakaoho io, e āhei ai te whakawhitiwhiti kōrero i waenga i ngā pūtau io me waenga i ngā pūtau io me ētahi atu wāhanga o te tinana. He mea nui te mārama ki tēnei ariā mō te ako i te āhua o te tinana, ahakoa mō te mātauranga ōkawa, te rangahau, ngā tono mahi rānei i roto i te rāngai hauora. Ka kapi i tēnei tuhinga te ariā taketake, ā, ka whakaratohia he tauira raruraru me ngā otinga hei āwhina i tō mārama ki tēnei tukanga.
Pendahuluan
Ko te pūnaha io he mea hanga ki te roro, te taurakira, me te whatunga io e horapa ana puta noa i te tinana. Ko tana mahi matua he whiwhi i ngā whakaohooho, he tukatuka i ngā mōhiohio, me te tuku whakahau ki ngā uaua me ngā repe. Ko ngā whakaoho io he tohu hiko e āhei ai te whakawhitiwhiti kōrero tere me te whai hua i roto i te pūnaha io.
Ko te pānga o te io, te pūmanawa mahi rānei, ka puta mai i te huringa ohorere o te ngaohiko puta noa i te kiriuhi o te pūtau io (neuron), i puta mai i te nekehanga o ngā katote konutai (Na+) me te pāhare pākawa (K+) puta noa i te kiriuhi. Ka tīmata tēnei tukanga ina whiwhi te neuron i tētahi whakaohooho kaha (e neke atu ana i tōna paepae), ka tīmata ai he raupapa o ngā mahi hiko me ngā mahi matū.
Ariā Taketake o te Tukanga Impulse Io
1. Pūmanawa Okioki: I raro i ngā āhuatanga okiokinga, he utu kino te roto o te neuron e pā ana ki tōna waho. Ko tēnei pūmanawa okiokinga he tata ki te -70 mV, e whakatauhia ana e te tohatoha o ngā iona Na+ me K+ me te nui ake o te Na+ i waho o te pūtau me te K+ i roto i te pūtau.
2. Te Whakaiti i te Polarization: Ina whiwhi te neuron i te whakaohooho e tika ana, ka tuwhera ngā awa ion Na+, ka taea ai e te Na+ te tomo ki te pūtau. Mā tēnei ka pai ake te āhua o roto o te pūtau, ā, ki te eke ki tētahi paepae, ka tīmatahia he pūmanawa mahi.
3. Te Whakapūtanga Anō: Kia tae ki te taumata teitei o te mahi, ka tīmata te kati o ngā awa Na+, ka tuwhera hoki ngā awa K+, ka puta te K+ i te pūtau, ā, ka hoki te utu ki te āhua kino i roto i te pūtau.
4. Te Whakapūngao Hiperu me te Pūmanawa Ātete: I ētahi wā, mā te tukunga o te K+ ka nui ake te kino o te pūmanawa kiriuhi i te wā okioki, e kiia nei ko te whakapūngao teitei. I te wāhanga pūmanawa ātete, kāore e taea e te neuron te tīmata i tētahi pūmanawa mahi hou, he uaua rawa rānei ki a ia.
5. Papu Konutai-Pōhā: Whai muri i te pūmanawa mahi, ka whakahokia e tēnei papu te tohatoha katote ki tōna āhua taketake mā te papu i te Na+ ki waho me te K+ ki roto i te pūtau.
Ngā Pātai Tauira me te Kōrero
Pātai 1
Whakamāramahia te tīmatanga o tētahi pūmanawa mahi, me tōna horapa i roto i tētahi neuron.
Kōrero:
Ka tīmata te pūmanawa mahi ina whiwhi te neuron i tētahi whakaohooho kaha hei eke, hei neke atu rānei i tōna paepae whakahekenga irahiko, arā, ko te -55 mV te nuinga o te wā. Kia tae ki tēnei paepae, ka tuwhera ngā hongere irahiko konutai e aro ana ki te ngaohiko, ka taea ai e ngā irahiko Na+ te neke tere ki roto i te neuron. Ka puta te whakahekenga irahiko o taua wāhanga o te kiriuhi o te neuron, ka pai ake ai.
I muri i te taenga o te whakahekenga o te polarization ki tōna taumata teitei, ka kati ngā hongere katote konutai, ā, ka tuwhera ngā hongere katote pāhare pākawa e aro ana ki te ngaohiko, ka whakahaere i te rere o ngā katote K+ mai i roto o te neuron ki waho. E mōhiotia ana tēnei tukanga ko te repolarization, i te mea ka hoki te membrane ki tōna pūmanawa okiokinga kino ake. Ka horapa te nekehanga io mā roto i tētahi tikanga whakaora i te taha o te axon, ka puta ngā tukanga whakahekenga me te repolarization i roto i ngā wāhanga rerekē o te membrane o te neuron.
Pātai 2
He aha te mahi a te pūmanawa ātete-kore ki te whakatau i te ahunga o te rere o te iri i roto i te axon o te neuron?
Kōrero:
E rua ngā wāhanga o te pūmanawa ātete: te ātete tino me te ātete whanaunga. I te wāhanga ātete tino, kāore e taea te whakaoho i te neuron ki te whakaputa i tētahi pūmanawa mahi hou, ahakoa te kaha o te whakaoho. Ka puta tēnei ina noho kore mahi ngā hongere Na+ ahakoa kua oti te whakahekenga polarization. I te wā o te wāhanga ātete whanaunga, ka taea te whakaoho i tētahi pūmanawa mahi hou, engari me kaha ake te whakaoho nā te mea he nui ake te polarization o te membrane.
He mea nui te pūmanawa ātete kia kotahi anake te huarahi e haere ai ngā ira io i te taha o te axon. Kia heke te pororaru o te wāhanga axon, ka uru atu ki te wā ātete, ka ārai i ngā ira kei hoki whakamuri. Nō reira, ka taea anake e ngā ira te haere whakamua ki te wāhanga e whai ake nei, kei te taumata okiokinga tonu, ā, kāore anō kia whakahohehia. Mā tēnei tukanga ka tukuna pai ngā tohu io ki te pito o te axon i te pito o te neuron.
Pātai 3
He aha te mea ka tupu mēnā ka whakararuraruhia te mahi a te papu konutai-pāhare pākawa i roto i tētahi neuron? Whakamāramahia te pānga ki te pūmanawa okiokinga.
Kōrero:
He mahi nui tā te papu konutai-pāhare pākawa (Na+/K+ ATPase) ki te pupuri i te pūmanawa okiokinga o ngā neuron mā te pupuhi i ngā iona Na+ e toru me ngā iona K+ e rua ki roto i te pūtau. E hiahiatia ana he pūngao mai i te ATP mō tēnei tukanga, ā, e pupuri ana i te pikinga kukū e tika ana mō te mahi noa a ngā neuron.
Ki te whakararuraruhia te mahi a tēnei papu, ka rerekē te tohatoha o ngā iona Na+ me K+ i roto, i waho hoki o te neuron, ka nui ake te Na+ e kohikohi ana i roto i te pūtau, ā, ka nui ake te K+ i waho o te pūtau. Ka puta te whakahekenga o te pūmanawa okiokinga i tēnei, ka nui ake te whakaoho o te neuron, ka kore rānei e taea te whakaputa i ngā nekehanga io nā te mea kāore e taea e te neuron te hoki ki tōna pūmanawa okiokinga paerewa. Hei tāpiri, ka taea e te kore taurite o te iona te whakararuraru i te mahi hiko o ētahi atu neuron, ā, ka arahi pea ki ngā raruraru pēnei i te hopuhopu, te arrhythmias, te kino rānei o ētahi atu pūtau io.
Whakamutunga
Hei mārama ki te tukanga whakaoho io, me mōhio pūmau ki te āhua o te kiriuhi io, te tohatoha katote, me te mahi a ngā pūmua kiriuhi pēnei i ngā hongere katote me ngā papu konutai-pāhare pākawa. Mā tēnei māramatanga ka taea e tātou te mārama ake ki ngā tikanga io me ngā mate rerekē ka puta. Mā te whakaharatau i ngā rapanga, ka taea te whakapakari i tō tātou māramatanga ki tēnei tukanga, ā, ka pai ake te whakarite i a tātou mō ngā pātai mātauranga me ngā āhuatanga haumanu ā muri ake nei.
