{"id":20213,"date":"2011-03-05T11:42:00","date_gmt":"2011-03-05T11:42:00","guid":{"rendered":"http:\/\/trainingsnews.com\/reglarea-umorala-hemodinamicii-2"},"modified":"2011-03-05T11:42:00","modified_gmt":"2011-03-05T11:42:00","slug":"reglarea-umorala-hemodinamicii-2","status":"publish","type":"post","link":"https:\/\/cvnextjob.com\/index.php\/2011\/03\/05\/reglarea-umorala-hemodinamicii-2\/","title":{"rendered":"Reglarea umoral\u0103 a hemodinamicii"},"content":{"rendered":"
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   Catecolaminele <\/span><\/div>\n
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            La om medulosuprarenalele descarc\u0103 \u00een circula\u0163ie un amestec de catecolamine \u00een care epinefrina reprezint\u0103 aproximativ 80% \u015fi norepinefrina 20%.<\/span><\/div>\n
Obi\u015fnuit concentra\u0163iile normale de catecolamine exercit\u0103 influen\u0163e minime asupra activit\u0103\u0163ii cordului \u015fi vaselor dar, c\u00e2nd concentra\u0163iile lor sanguine cresc catecolaminele produc importante modific\u0103ri ale distribu\u0163iei fluxului sanguin.<\/span> <\/span><\/div>\n
Norepinefrina activeaz\u0103 predominant receptorii ?, care se g\u0103sesc mai abundent \u00een arteriolele renale, cutanate, splahnice \u015fi  din musculatura scheletic\u0103 \u015fi \u00een venulele \u015fi venele cutanate \u015fi splahnice, de aceea produce o vasoconstic\u0163ie mai intens\u0103 \u00een aceste teritorii, precum \u015fi receptorii \u03b21, care mediaz\u0103 efectele sale cardiace \u015fi vasculare similare cu cele ale norepinefrinei, dar mai slabe, concomitent cu dilata\u0163ia puternic\u0103 a vaselor musculaturii scheletice (urmarea activ\u0103rii receptorilor <\/span>\u03b2<\/span>2).<\/span><\/div>\n
            Dopamina, cea de a treia catecolamin\u0103 eliberat\u0103 \u00een circula\u0163ie ac\u0163ioneaz\u0103 asupra unor receptori specifici, dintre care unii (receptorii D1) activeaz\u0103 adenilatciclaza \u015fi al\u0163ii (receptorii D2), ac\u0163ioneaz\u0103 prin alte mecanisme \u00eenc\u0103 neprecizate, exercitnd efecte stimulante asupra cordului (efect <\/span>\u03b2<\/span>1 adrenergic), m\u0103rind debitul cardiac, mai ales prin cre\u015fterea for\u0163ei de contrac\u0163ie miocardic\u0103 \u015fi mai pu\u0163in prin cre\u015fterea frecven\u0163ei \u015fi, concomitent, produce vasoconstric\u0163ie renal\u0103, mezenteric\u0103, coronarian\u0103 \u015fi cerebral\u0103.<\/span><\/div>\n
            Sistemul renin\u0103-angiotensin\u0103 \u00een condi\u0163ii fiziologice nu produce efecte circulatorii sistemice prinn ac\u0163iune vasoconstrictoare direct\u0103, angiotensina ac\u0163ioneaz\u0103 doar intrarenal, contribuind la autoreglarea iriga\u0163iei renale. <\/span><\/div>\n
            Vasopresina (ADH), \u00een doze mari, s-a dovedit un vasoconstrictor foarte puternic, justific\u00e2nd denumirea de vasopresin\u0103, dar cantit\u0103\u0163ile fiziologice existente \u00een condi\u0163ii obi\u015fnuite \u00een plasm\u0103 se consider\u0103 c\u0103 sunt prea mici ca s\u0103 influen\u0163eze tonusul vascular. <\/span><\/div>\n
Cercet\u0103ri mai recente demonstreaz\u0103 \u00eens\u0103 c\u0103 \u015fi \u00een doze apropiate de cele fiziologice, ADH poate provoca constric\u0163ia unor paturi vasculare (musculatura scheletic\u0103, rinichi, coronare) prin ac\u0163iune direct\u0103, precum \u015fi indirect poten\u0163\u00e2nd ac\u0163iunile norepinefrinei.<\/span><\/div>\n
            Hormonii tiroidieni exercit\u0103 asupra sistemului cardiovascular ac\u0163iuni similare cu cele ale catecolaminelor, cu care de altfel au interrela\u0163ii foarte str\u00e2nse.<\/span><\/div>\n
            Mineralocorticoizii suprarenalieni nu influen\u0163eaz\u0103 direct tonusul vascular, \u00een shimb, prin faptul c\u0103 provoac\u0103 acumulare de Na+ \u015fi ap\u0103 \u00een pere\u0163ii vasculari m\u0103resc responsivitatea vaselor la stimulii constrictori fiziologici \u015fi la activitatea reflex\u0103 simpatic\u0103. <\/span><\/div>\n
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Mai recent (Thibault \u015fi colab.,1983) s-a identificat un factor natriuretic atrial (auriculina, atriopeptina) care este sintetizat de miocitele atriale la stimularea prin distensie a atriului drept \u015fi vaselor pulmonare. <\/span><\/div>\n
Acest factor care se al\u0103tur\u0103 factorului natriuretic hipotalamic, ar fi un polipeptid (cu greutate molecular\u0103 de 400 daltoni \u015fi cu 151 de aminoacizi) care exercit\u0103 efecte depresoare at\u00e2t prin poten\u0163area natriurezei c\u00e2t \u015fi prin ac\u0163iune direct\u0103, relaxant\u0103 asupra musculaturii netede vasculare.<\/span><\/div>\n
 Factori tisulari locali , printre care prostaglandinele, serotonina (5-HT),Histamina, bradikinina, CO2  , oxidul nitric, prostacicline, neurotensin\u0103 intervin \u00een modularea efectelor controlului cardiovascular at\u00e2t \u00een condi\u0163iii fiziologice c\u00e2t \u015fi patologice.<\/span><\/div>\n
\n<\/div>\n","protected":false},"excerpt":{"rendered":"

   Catecolaminele             La om medulosuprarenalele descarc\u0103 \u00een circula\u0163ie un amestec de catecolamine \u00een care epinefrina reprezint\u0103 aproximativ 80% \u015fi norepinefrina 20%. Obi\u015fnuit concentra\u0163iile normale de catecolamine exercit\u0103 influen\u0163e minime asupra activit\u0103\u0163ii cordului \u015fi vaselor dar, c\u00e2nd concentra\u0163iile lor sanguine cresc catecolaminele produc importante modific\u0103ri ale distribu\u0163iei fluxului sanguin. Norepinefrina activeaz\u0103 predominant receptorii ?, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[11],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts\/20213"}],"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\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/comments?post=20213"}],"version-history":[{"count":0,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts\/20213\/revisions"}],"wp:attachment":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/media?parent=20213"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/categories?post=20213"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/tags?post=20213"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}