{"id":107741,"date":"2018-02-17T16:10:00","date_gmt":"2018-02-17T16:10:00","guid":{"rendered":""},"modified":"2023-01-08T10:37:52","modified_gmt":"2023-01-08T10:37:52","slug":"centrii-cardiovasculari-3","status":"publish","type":"post","link":"https:\/\/cvnextjob.com\/index.php\/2018\/02\/17\/centrii-cardiovasculari-3\/","title":{"rendered":"Centrii cardiovasculari"},"content":{"rendered":"
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Centrii bulbopontini reprezint\u0103 zona principal\u0103 unde sunt prelucrate informa\u0163iile corelate cu activitatea reflex\u0103 cardiovascular\u0103. \u00cen forma\u0163ia reticulat\u0103 din por\u0163iunea inferioar\u0103 a trunchiului cerebral, mai exact \u00een cele 2\/3 superioare ale bulbului ( deasupra obexului \u00een regiunea ariei postrema) \u015fi 1\/3 inferioar\u0103 a protuberan\u0163ei ( deasupra nucleilor vestibulari ), din plan\u015feul ventriculului patru, ventral aproape p\u00e2n\u0103 la piramide, se afl\u0103 o arie larg\u0103, difuz\u0103, denumit\u0103 clasic centrul vasomotor. Se descrie \u015fi un centru cardioinhibitor, constituit, \u00een mare parte, de nucleul ambiguu bulbar.<\/span><\/div>\n
            Cercet\u0103rile cu microelectrozi au stabilit c\u0103 stimularea zonelor rostrale \u015fi laterale ale acestei arii determin\u0103 cre\u015fterea tonusului vascular (vasoconstric\u0163ie), hipertensiune \u015fi tahicardie- reflex presor (fig. 41), \u00een timp ce stimularea unor regiuni mai restr\u00e2nse \u00een jurul obexului produce vasodilata\u0163ie, hipotensiune \u015fi bradicardie \u2013 reflex depresor (fig.42), cele dou\u0103 autoritmice fiind \u00een rela\u0163ie de inerva\u0163ie reciproc\u0103.          <\/span><\/div>\n
            “Centrul” cardiovasomotor pare a fi compus din dou\u0103 por\u0163iuni: o zon\u0103 excitatoare, cuprinz\u00e2nd por\u0163iunile laterale ale forma\u0163iunii reticulate, a c\u0103rei excitare determin\u0103 stimularea simpaticului, urmat\u0103 de vasoconstric\u0163ie bilateral\u0103 \u015fi accelerarea frecven\u0163ei cardiace \u015fi o zon\u0103 inhibitoare, medial\u0103, care inhib\u0103 activitatea simpaticului, produc\u00e2nd vasodilata\u0163ie \u015fi r\u0103rirea frecven\u0163ei cardiace  8rezultat \u015fi al stimul\u0103rii directe a nucleului dorsal vagal).<\/span><\/div>\n
Centrul cardiovasomotor este conceput, deci, ca un mecanism de barostat reglabil, prev\u0103zut cu tonus \u015fi automatism propriu, care ac\u0163ioneaz\u0103 ca un tot unitar, determin\u00e2nd modific\u0103ri coordonate concomitente cardiace \u015fi vasculare, de obicei fiind asociate cre\u015fterea frecven\u0163ei cardiace cu vasoconstric\u0163ie, sau sc\u0103derea frecven\u0163ei cardiace cu vasodilata\u0163ie, aceste interrela\u0163ii nefiind \u00eens\u0103 obligatorii \u015fi invariabile.<\/span><\/div>\n
            Nucleul dorsal al vagului, denumit \u00eenainte centrul cardioinhibitor, se afl\u0103 de asemenea \u00een forma\u0163iunea reticulat\u0103, lateral centrului cardiovasomotor, fiind centrul care genereaz\u0103 desc\u0103rc\u0103rile tonice vagale \u00een repaus. Acest centru prime\u015fte aferen\u0163e de la nivelul baro- \u015fi chemoreceptorilor, impulsuri care \u00eei men\u0163in \u015fi moduleaz\u0103 activitatea tonic\u0103. Denervarea sinoaortic\u0103 abole\u015fte aproape tonusul vagal, demonstr\u00e2nd c\u0103 neuronii din nucleul dorsal (visceromotor) al vagului nu sunt activi dec\u00e2t \u00een prezen\u0163a influen\u0163elor aferen\u0163iale, din acest punct de vedere diferind de “centrul” cardiovasomotor, care posed\u0103 o activitate tonic\u0103 permanent\u0103, intensificat\u0103 chiar prin deaferentare sinoaortic\u0103.<\/span><\/div>\n
            Activitatea reflex\u0103 a centrilor pontobulbari (barostatul) este influen\u0163at\u0103 permanent de aferen\u0163ele baro- \u015fi chemoreceptoare de la nivelul zonelor reflexogene specifice, sau din alte teritorii nespecifice (pe calea forma\u0163iunii reticulate), influen\u0163at\u0103, \u00eentre\u0163inut\u0103 \u015fi adecvat\u0103 solicit\u0103rilor \u015fi circumstan\u0163elor \u015fi de con\u0163inutul \u00een CO2  , O2  \u015fi H+ al s\u00e2ngelui care ac\u0163ioneaz\u0103 direct asupra centrilor sau indirect prin intermediul chemoreceptorilor.<\/span><\/div>\n
            Activitatea centrilor bulbopontini este corelat\u0103 \u015fi cu cea a altor centri bulbari, \u00een special cu cea a centrilor respiratori. Respira\u0163ia obi\u015fnuit\u0103 nu influen\u0163eaz\u0103 la adult activitatea cardiac\u0103, \u00een schimb, \u00een timpul respira\u0163iilor profunde frecven\u0163a cardiac\u0103 se accelereaz\u0103 \u00een inspira\u0163ie \u015fi se r\u0103re\u015fte \u00een expira\u0163ie (aritmie sinusal\u0103, prezent\u0103 la copii \u015fi \u00een timpul respira\u0163iei obi\u015fnuite).<\/span><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Centrii bulbopontini reprezint\u0103 zona principal\u0103 unde sunt prelucrate informa\u0163iile corelate cu activitatea reflex\u0103 cardiovascular\u0103. \u00cen forma\u0163ia reticulat\u0103 din por\u0163iunea inferioar\u0103 a trunchiului cerebral, mai exact \u00een cele 2\/3 superioare ale bulbului ( deasupra obexului \u00een regiunea ariei postrema) \u015fi 1\/3 inferioar\u0103 a protuberan\u0163ei ( deasupra nucleilor vestibulari ), din plan\u015feul ventriculului patru, ventral aproape p\u00e2n\u0103 […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts\/107741"}],"collection":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/comments?post=107741"}],"version-history":[{"count":0,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts\/107741\/revisions"}],"wp:attachment":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/media?parent=107741"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/categories?post=107741"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/tags?post=107741"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}