{"id":20222,"date":"2011-03-05T11:36:00","date_gmt":"2011-03-05T11:36:00","guid":{"rendered":"http:\/\/trainingsnews.com\/mecanismele-intrinseci-cardiace-2"},"modified":"2011-03-05T11:36:00","modified_gmt":"2011-03-05T11:36:00","slug":"mecanismele-intrinseci-cardiace-2","status":"publish","type":"post","link":"https:\/\/cvnextjob.com\/index.php\/2011\/03\/05\/mecanismele-intrinseci-cardiace-2\/","title":{"rendered":"Mecanismele intrinseci cardiace"},"content":{"rendered":"
<\/div>
Sunt demonstrate de faptul c\u0103 inima scoas\u0103 din organism, deci lipsit\u0103 de influen\u0163e exterioare, continu\u0103 s\u0103 se contracte \u015fi chiar \u00ee\u015fi poate adapta \u00een anumite limite debitul prin modific\u0103ri adecvate de frecven\u0163\u0103 \u015fi\/sau ale volumului sistolic. <\/span><\/div>\n
Frecven\u0163a cardiac\u0103 (ce poate cre\u015fte cu 10-30% fa\u0163\u0103 de nivelul bazal ) este influen\u0163at\u0103 prin destinderea pasiv\u0103 a pere\u0163ilor atriuului drept.<\/span><\/div>\n
Volumul cardiac este influen\u0163at “in vivo” de trei factori:<\/span><\/div>\n
1.   presarcina<\/span><\/u> (sau gradul de \u00eentindere a fibrei miocardice \u00eenainte de \u00eenceputul sistolei);<\/span><\/div>\n
2.   contractilitatea miocardului<\/span><\/u>;<\/span><\/div>\n
3.   postsarcina<\/span><\/u> ( sau rezisten\u0163a opus\u0103 s\u00e2ngelui de c\u0103tre tonusul vascular).<\/span><\/div>\n
Adaptarea prin mecanisme intrinseci a fost demonstrat\u0103 experimental pe un preparat “cord-pulmon” lipsit de inerva\u0163ie prin \u00eentreruperea circula\u0163iei cerebrale de c\u0103tre Frank (1895) \u015fi Starling (1910) stabilindu-se “legea inimii” sau legea Frank-Starling. At\u00e2t \u00een condi\u0163ii de \u00eentoarcere venoas\u0103 crescut\u0103 (presarcina) c\u00e2t \u015fi \u00een condi\u0163iile cre\u015fterii presiunii \u00een aort\u0103 (postsarcina) for\u0163a de contrac\u0163ie a miocardului poate cre\u015fte peste valoarea de repaus prin \u00eentinderea fibrei musculare, for\u0163a fiind direct propor\u0163ional\u0103 cu gradul de alungire a fibrei (p\u00e2n\u0103 la o alungire maximal\u0103, adic\u0103 120% fa\u0163\u0103 de condi\u0163iile de repaus).<\/span><\/div>\n
            Prin cre\u015fterea volumului telediastolic sarcomerele devin u\u015for alungite cresc\u00e2ndu-se astfel num\u0103rul situsurilor pentru interac\u0163iunea dintre filamentele de actin\u0103 \u015fi cele de miozin\u0103, gradul de \u00eentrep\u0103trundere (glisare) cresc\u00e2nd realiz\u00e2ndu-se situarea filamentelor \u00eentr-o pozi\u0163ie de interdigita\u0163ie optim\u0103 pentru contrac\u0163ie. Inima nu arunc\u0103 \u00een circula\u0163ie toat\u0103 cantitatea de s\u00e2nge din ventriculul st\u00e2ng unde se acumuleaz\u0103 o rezerv\u0103 de s\u00e2nge (cre\u015fterea volumului telediastolic sau diastolic final) care produce o \u00eentindere mai accentuat\u0103 a fibrelor miocardice astfel \u00eenc\u00e2t dup\u0103 15-30 secunde se va stabili un nou echilibru cu expulzarea \u00eentregii cantit\u0103\u0163i de s\u00e2nge din ventricul.<\/span><\/div>\n","protected":false},"excerpt":{"rendered":"

Sunt demonstrate de faptul c\u0103 inima scoas\u0103 din organism, deci lipsit\u0103 de influen\u0163e exterioare, continu\u0103 s\u0103 se contracte \u015fi chiar \u00ee\u015fi poate adapta \u00een anumite limite debitul prin modific\u0103ri adecvate de frecven\u0163\u0103 \u015fi\/sau ale volumului sistolic. Frecven\u0163a cardiac\u0103 (ce poate cre\u015fte cu 10-30% fa\u0163\u0103 de nivelul bazal ) este influen\u0163at\u0103 prin destinderea pasiv\u0103 a pere\u0163ilor […]<\/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\/20222"}],"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=20222"}],"version-history":[{"count":0,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts\/20222\/revisions"}],"wp:attachment":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/media?parent=20222"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/categories?post=20222"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/tags?post=20222"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}