Myogenic mechanism (original) (raw)
El mecanismo miogénico se refiere al mecanismo por el cual las arterias y arteriolas reaccionan ante un aumento o descenso de la presión arterial para mantener el flujo sanguíneo dentro de lo normal en los vasos sanguíneos * Datos: Q6947924
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| dbo:abstract | El mecanismo miogénico se refiere al mecanismo por el cual las arterias y arteriolas reaccionan ante un aumento o descenso de la presión arterial para mantener el flujo sanguíneo dentro de lo normal en los vasos sanguíneos El músculo liso de los vasos sanguíneos reacciona al estiramiento del músculo abriendo canales iónicos, que causan la despolarización del músculo. Esto reduce significativamente el volumen de sangre capaz de pasar a través de la luz, por lo que se reduce el flujo sanguíneo a través de los capilares. Alternativamente, cuando el Músculo Liso en los vasos sanguíneos se relaja, los canales iónicos se cierran, resultando una vasodilatación de los vasos sanguíneos. Esto incrementa el flujo sanguíneo a través de la luz. * Datos: Q6947924 (es) The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow constant within the blood vessel. Myogenic response refers to a contraction initiated by the myocyte itself instead of an outside occurrence or stimulus such as nerve innervation. Most often observed in (although not necessarily restricted to) smaller resistance arteries, this 'basal' myogenic tone may be useful in the regulation of organ blood flow and peripheral resistance, as it positions a vessel in a preconstricted state that allows other factors to induce additional constriction or dilation to increase or decrease blood flow. The smooth muscle of the blood vessels reacts to the stretching of the muscle by opening ion channels, which cause the muscle to depolarize, leading to muscle contraction. This significantly reduces the volume of blood able to pass through the lumen, which reduces blood flow through the blood vessel. Alternatively when the smooth muscle in the blood vessel relaxes, the ion channels close, resulting in vasodilation of the blood vessel; this increases the rate of flow through the lumen. This system is especially significant in the kidneys, where the glomerular filtration rate (the rate of blood filtration by the nephron) is particularly sensitive to changes in blood pressure. However, with the aid of the myogenic mechanism, the glomerular filtration rate remains very insensitive to changes in human blood pressure. Myogenic mechanisms in the kidney are part of the autoregulation mechanism which maintains a constant renal blood flow at varying arterial pressure. Concomitant autoregulation of glomerular pressure and filtration indicates regulation of preglomerular resistance. Model and experimental studies were performed to evaluate two mechanisms in the kidney, myogenic response and tubuloglomerular feedback. A mathematical model showed good autoregulation through a myogenic response, aimed at maintaining a constant wall tension in each segment of the preglomerular vessels. Tubuloglomerular feedback gave rather poor autoregulation. The myogenic mechanism showed 'descending' resistance changes, starting in the larger arteries, and successively affecting downstream preglomerular vessels at increasing arterial pressures. This finding was supported by micropuncture measurements of pressure in the terminal interlobular arteries. Evidence that the mechanism was myogenic was obtained by exposing the kidney to a subatmospheric pressure of 40 mmHg; this led to an immediate increase in renal resistance, which could not be prevented by denervation or various blocking agents. (en) Il meccanismo miogenico è il modo in cui arterie ed arteriole reagiscono ad un aumento o diminuzione della pressione sanguigna per mantenere costante il flusso di sangue all'interno dei vasi sanguigni. Il muscolo liscio dei vasi sanguigni reagisce allo stiramento del muscolo aprendo i canali ionici, che causano la depolarizzazione del muscolo, portando alla contrazione muscolare: ciò riduce significativamente il volume di sangue in grado di passare attraverso il lume, che a sua volta riduce il flusso di sangue attraverso il vaso sanguigno. Al contrario, quando la muscolatura liscia del vaso sanguigno si rilassa, i canali ionici si chiudono con conseguente vasodilatazione dei vasi sanguigni, questo aumenta la velocità di flusso attraverso il vaso. Questo sistema è particolarmente importante nei reni, dove il tasso di filtrazione glomerulare, cioè la velocità di filtrazione del sangue da parte del nefrone, è particolarmente sensibile ai cambiamenti di pressione sanguigna. Tuttavia, con l'aiuto del meccanismo miogenico, la velocità di filtrazione glomerulare diviene meno sensibile alle variazioni di pressione. Il meccanismo miogenico nel rene sono parte del meccanismo di autoregolazione che mantiene costante il flusso ematico renale al variare della pressione arteriosa. L'autoregolazione della pressione glomerulare e di filtrazione indica la regolazione delle resistenze preglomerulari. Studi sperimentali sono stati condotti per valutare i due meccanismi nel rene, la risposta miogenica e il feedback tubuloglomerulare. Un modello matematico ha dimostrato una buona autoregolazione attraverso il meccanismo miogenico, inteso a mantenere una tensione costante nella parete in ogni segmento dei vasi preglomerulari. Il feedback tubuloglomerulare dà una scarsa autoregolazione. Il meccanismo miogeno modula cambiamenti di resistenza decrescenti, a partire dalle arterie più grandi e successivamente sino vasi preglomerulari a valle per aumentare la pressione arteriosa. Questo risultato è stato sostenuto da misurazioni con micropunture nelle arterie interlobulari terminali; la prova che il meccanismo era miogenico è stata ottenuta esponendo il rene ad una pressione "subatmosferica" di 40 mmHg; questo ha portato ad un aumento immediato delle resistenze renali, che non poteva essere impedito da denervazione o da vari agenti bloccanti. (it) Миогéнный механи́зм — основной механизм регуляции физиологических систем, основанный на ответной реакции гладких миоцитов на растяжение. Дело в том, что сокращение миоцитов зависит от степени их растяжения. В этом случае ответ относится к сокращению, инициированному самим миоцитом, а не внешним явлением или стимулом, таким как нервный импульс. Такой отличительной особенностью, как миогенный механизм регуляции, в большинстве случаев обладают миоциты, имеющие свойство автоматии: пейсмейкеры/водители ритма (в сердечной мышце). Артерии и артериолы реагируют на увеличение или уменьшение кровяного давления, чтобы сохранить объем крови внутри кровеносных сосудов постоянным. (ru) |
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| rdfs:comment | El mecanismo miogénico se refiere al mecanismo por el cual las arterias y arteriolas reaccionan ante un aumento o descenso de la presión arterial para mantener el flujo sanguíneo dentro de lo normal en los vasos sanguíneos * Datos: Q6947924 (es) The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow constant within the blood vessel. Myogenic response refers to a contraction initiated by the myocyte itself instead of an outside occurrence or stimulus such as nerve innervation. Most often observed in (although not necessarily restricted to) smaller resistance arteries, this 'basal' myogenic tone may be useful in the regulation of organ blood flow and peripheral resistance, as it positions a vessel in a preconstricted state that allows other factors to induce additional constriction or dilation to increase or decrease blood flow. (en) Il meccanismo miogenico è il modo in cui arterie ed arteriole reagiscono ad un aumento o diminuzione della pressione sanguigna per mantenere costante il flusso di sangue all'interno dei vasi sanguigni. (it) Миогéнный механи́зм — основной механизм регуляции физиологических систем, основанный на ответной реакции гладких миоцитов на растяжение. Дело в том, что сокращение миоцитов зависит от степени их растяжения. В этом случае ответ относится к сокращению, инициированному самим миоцитом, а не внешним явлением или стимулом, таким как нервный импульс. Такой отличительной особенностью, как миогенный механизм регуляции, в большинстве случаев обладают миоциты, имеющие свойство автоматии: пейсмейкеры/водители ритма (в сердечной мышце). (ru) |
| rdfs:label | Mecanismo miogénico (es) Meccanismo miogenico (it) Myogenic mechanism (en) Миогенный механизм (ru) |
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