{"id":53389,"date":"2019-11-30T00:00:00","date_gmt":"2019-11-29T21:00:00","guid":{"rendered":"https:\/\/prohoster.info\/blog\/blog_prohoster\/malenkij-sekret-bolshogo-serdtsa-pervaya-v-istorii-kardiogramma-sinego-kita"},"modified":"2020-02-18T14:01:17","modified_gmt":"2020-02-18T11:01:17","slug":"malenkij-sekret-bolshogo-serdtsa-pervaya-v-istorii-kardiogramma-sinego-kita","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/malenkij-sekret-bolshogo-serdtsa-pervaya-v-istorii-kardiogramma-sinego-kita","title":{"rendered":"Mal\u00e9 tajemstv\u00ed velk\u00e9ho srdce: prvn\u00ed kardiogram modr\u00e9 velryby v historii","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

\"Mal\u00e9
\n
\nJe t\u011b\u017ek\u00e9 polemizovat s tvrzen\u00edm, \u017ee nej\u017eiv\u011bj\u0161\u00ed p\u0159edstavivost m\u00e1 pr\u00e1v\u011b p\u0159\u00edroda. Ka\u017ed\u00fd z\u00e1stupce fl\u00f3ry a fauny m\u00e1 sv\u00e9 jedine\u010dn\u00e9 a ob\u010das i podivn\u00e9 vlastnosti, kter\u00e9 n\u00e1m \u010dasto ned\u00e1vaj\u00ed smysl. Vezm\u011bme si nap\u0159\u00edklad raka bogomola. Tento drav\u00fd tvor je schopen za\u00fato\u010dit na svou ob\u011b\u0165 nebo nep\u0159\u00edtele sv\u00fdmi siln\u00fdmi klepety rychlost\u00ed 83 km\/h, a jejich zrakov\u00fd syst\u00e9m je jedn\u00edm z nejslo\u017eit\u011bj\u0161\u00edch, kter\u00e9 kdy \u010dlov\u011bk zkoumal. Raci bogomolov\u00e9, a\u010dkoliv jsou zu\u0159iv\u00ed, nejsou p\u0159\u00edli\u0161 velc\u00ed \u2014 dor\u016fstaj\u00ed a\u017e do 35 cm. Nejv\u011bt\u0161\u00edm obyvatelem mo\u0159\u00ed a oce\u00e1n\u016f, jak na t\u00e9to planet\u011b, je modr\u00e1 velryba. D\u00e9lka tohoto savce m\u016f\u017ee p\u0159esahovat v\u00edce ne\u017e 30 metr\u016f a v\u00e1\u017eit 150 tun. Navzdory impozantn\u00edm rozm\u011br\u016fm nem\u016f\u017eeme modr\u00e9 velryby pova\u017eovat za ob\u00e1van\u00e9 lovce, proto\u017ee d\u00e1vaj\u00ed p\u0159ednost planktonu.<\/p>\n

Anatomie modr\u00fdch velryb v\u017edy zaj\u00edmala v\u011bdce, kte\u0159\u00ed cht\u011bj\u00ed l\u00e9pe pochopit, jak pracuje tak obrovsk\u00fd organismus a jeho org\u00e1ny. I kdy\u017e o existenci modr\u00fdch velryb v\u00edme ji\u017e n\u011bkolik set let (od roku 1694, pokud jsme p\u0159esn\u00ed), ti\u0161i ob\u0159i neodhalili v\u0161echny sv\u00e9 tajemstv\u00ed. Dnes se sezn\u00e1m\u00edme se studiem, ve kter\u00e9m skupina v\u011bdc\u016f ze Stanfordsk\u00e9 univerzity vyvinula za\u0159\u00edzen\u00ed, kter\u00e9 umo\u017enilo po\u0159\u00eddit prvn\u00ed z\u00e1znamy srde\u010dn\u00edho tepu modr\u00e9 velryby. Jak funguje srdce p\u00e1na mo\u0159\u00ed, jak\u00e9 objevy v\u011bdci u\u010dinili a pro\u010d nem\u016f\u017ee existovat organismus v\u011bt\u0161\u00ed ne\u017e modr\u00e1 velryba? O tom se dozv\u00edme z v\u00fdstavy v\u00fdzkumn\u00e9 skupiny. Jdeme na to.<\/a><\/noindex><\/p>\n

Hrdina v\u00fdzkumu<\/h3>\n

\nModr\u00e1 velryba je nejv\u011bt\u0161\u00ed savec, nejv\u011bt\u0161\u00ed obyvatel mo\u0159\u00ed a oce\u00e1n\u016f, nejv\u011bt\u0161\u00ed zv\u00ed\u0159e, nejv\u011bt\u0161\u00ed velryba. Co dodat, modr\u00e1 velryba je opravdu nejv\u011bt\u0161\u00ed ve v\u0161ech dimenz\u00edch \u2014 d\u00e9lka 33 metr\u016f, v\u00e1ha 150 tun. Tyto \u010d\u00edsla jsou orienta\u010dn\u00ed, ale i tak jsou ohromuj\u00edc\u00ed.<\/p>\n

\"Mal\u00e9
\n
\nDokonce hlava tohoto giganta si zaslou\u017e\u00ed zvl\u00e1\u0161tn\u00ed \u0159\u00e1dek v knize rekord\u016f Guiness, proto\u017ee tvo\u0159\u00ed p\u0159ibli\u017en\u011b 27 % z celkov\u00e9 d\u00e9lky t\u011bla. O\u010di modr\u00fdch velryb jsou p\u0159itom pom\u011brn\u011b mal\u00e9, ne v\u011bt\u0161\u00ed ne\u017e grapefruit. Pokud se v\u00e1m bude t\u011b\u017eko d\u00edvat na o\u010di velryby, \u00fasta si v\u0161imnete okam\u017eit\u011b. Tlamu modr\u00e9 velryby m\u016f\u017ee pojmout a\u017e 100 lid\u00ed (stra\u0161ideln\u00fd p\u0159\u00edklad, ale modr\u00e9 velryby lidi ne\u017eerou, aspo\u0148 ne \u00famysln\u011b). Velk\u00e1 velikost \u00fast je d\u00e1na gastronomick\u00fdmi preferencemi: velryby j\u00ed plankton, polykaj\u00edc\u00ed obrovsk\u00e9 objemy vody, kterou pak vypou\u0161t\u011bj\u00ed pomoc\u00ed filtra\u010dn\u00edho za\u0159\u00edzen\u00ed, p\u0159i\u010dem\u017e vyfiltrovan\u00e9 j\u00eddlo z\u016fst\u00e1v\u00e1. Za dost p\u0159\u00edzniv\u00fdch okolnost\u00ed modr\u00e1 velryba zkonzumuje za den p\u0159ibli\u017en\u011b 6 tun planktonu.<\/p>\n

\"Mal\u00e9
\n
\nDal\u0161\u00edm d\u016fle\u017eit\u00fdm rysem modr\u00fdch velryb jsou jejich pl\u00edce. Jsou schopny zadr\u017eet dech a\u017e na 1 hodinu a potopit se do hloubky a\u017e 100 m. Stejn\u011b jako ostatn\u00ed mo\u0159\u0161t\u00ed savci modr\u00e9 velryby ob\u010das vyplouvaj\u00ed na hladinu, aby se nadechly. Po vyplut\u00ed na hladinu velryby pou\u017e\u00edvaj\u00ed d\u00fdchac\u00ed otvor \u2014 otvor pro d\u00fdch\u00e1n\u00ed z dvou velk\u00fdch otvor\u016f (nosn\u00edch d\u00edrek) na zadn\u00ed \u010d\u00e1sti hlavy. V\u00fddech velryby p\u0159es d\u00fdchac\u00ed otvor je \u010dasto doprov\u00e1zen vertik\u00e1ln\u00edm gejz\u00edrem vody vysok\u00fdm a\u017e 10 m. Vzhledem k podm\u00ednk\u00e1m ob\u00fdv\u00e1n\u00ed velryb funguj\u00ed jejich pl\u00edce mnohem efektivn\u011bji ne\u017e na\u0161e \u2014 pl\u00edce velryby absorbuj\u00ed 80-90 % kysl\u00edku, zat\u00edmco na\u0161e pouze asi 15 %. Objem plic je p\u0159ibli\u017en\u011b 3000 litr\u016f, zat\u00edmco u \u010dlov\u011bka se tento \u00fadaj pohybuje kolem 3-6 litr\u016f.<\/p>\n

\"Mal\u00e9
\nModel srdce modr\u00e9 velryby v muzeu v New Bedfordu (USA).<\/i><\/p>\n

C\u00e9vn\u00ed syst\u00e9m modr\u00e9 velryby je rovn\u011b\u017e pln\u00fd rekordn\u00edch parametr\u016f. Nap\u0159\u00edklad c\u00e9vy jsou obrovsk\u00e9, pr\u016fm\u011br jedin\u00e9 aorty \u010din\u00ed p\u0159ibli\u017en\u011b 40 cm. Srdce modr\u00fdch velryb je pova\u017eov\u00e1no za nejv\u011bt\u0161\u00ed srdce na sv\u011bt\u011b a v\u00e1\u017e\u00ed p\u0159ibli\u017en\u011b jednu tunu. S tak velk\u00fdm srdcem m\u00e1 velryba tak\u00e9 hodn\u011b krve \u2014 v\u00edce ne\u017e 8000 litr\u016f u dosp\u011bl\u00e9 jedince.<\/p>\n

A nyn\u00ed jsme se plynule dostali k podstat\u011b samotn\u00e9ho v\u00fdzkumu. Srdce modr\u00e9 velryby je velk\u00e9, jak jsme ji\u017e pochopili, ale bije pom\u011brn\u011b pomalu. D\u0159\u00edve se p\u0159edpokl\u00e1dalo, \u017ee puls \u010din\u00ed p\u0159ibli\u017en\u011b 5-10 \u00fader\u016f za minutu, ve vz\u00e1cn\u00fdch p\u0159\u00edpadech a\u017e 20. Av\u0161ak nikdo dosud neprov\u00e1d\u011bl p\u0159esn\u00e1 m\u011b\u0159en\u00ed.<\/p>\n

V\u011bdci ze Stanfordovy univerzity tvrd\u00ed, \u017ee m\u011b\u0159\u00edtko v biologii m\u00e1 obrovsk\u00fd v\u00fdznam, zejm\u00e9na pokud jde o ur\u010den\u00ed funk\u010dn\u00edch vlastnost\u00ed org\u00e1n\u016f \u017eiv\u00fdch bytost\u00ed. Studium r\u016fzn\u00fdch organism\u016f, od my\u0161\u00ed po velryby, pom\u00e1h\u00e1 ur\u010dit limity rozm\u011br\u016f, kter\u00e9 \u017eiv\u00fd organismus nem\u016f\u017ee p\u0159ekro\u010dit. Srdce a kardiovaskul\u00e1rn\u00ed syst\u00e9m jako celek jsou d\u016fle\u017eit\u00fdmi atributy takov\u00fdchto v\u00fdzkum\u016f.<\/p>\n

U mo\u0159sk\u00fdch savc\u016f, jejich\u017e fyziologie se pln\u011b p\u0159izp\u016fsobila jejich zp\u016fsobu \u017eivota, hraj\u00ed d\u016fle\u017eitou roli adaptace spojen\u00e9 s pot\u00e1p\u011bn\u00edm a zadr\u017een\u00edm dechu. Bylo zji\u0161t\u011bno, \u017ee u mnoha takov\u00fdch organism\u016f b\u011bhem pono\u0159en\u00ed kles\u00e1 srde\u010dn\u00ed frekvence na \u00farove\u0148 pod klidov\u00fdm stavem. Po vystoupen\u00ed na povrch se srde\u010dn\u00ed rytmus zrychluje. <\/p>\n

Sn\u00ed\u017een\u00e1 srde\u010dn\u00ed frekvence b\u011bhem pono\u0159en\u00ed je nezbytn\u00e1 pro sn\u00ed\u017een\u00ed rychlosti dod\u00e1v\u00e1n\u00ed kysl\u00edku do tk\u00e1n\u00ed a bun\u011bk, \u010d\u00edm\u017e se zpomaluje proces vy\u010derp\u00e1n\u00ed kysl\u00edkov\u00fdch z\u00e1sob v krvi a sni\u017euje se spot\u0159eba kysl\u00edku samotn\u00fdm srdcem. <\/p>\n

Existuje hypot\u00e9za, \u017ee cvi\u010den\u00ed (tj. zv\u00fd\u0161en\u00e1 fyzick\u00e1 aktivita) moduluje reakci na pono\u0159en\u00ed a zvy\u0161uje srde\u010dn\u00ed frekvenci b\u011bhem pot\u00e1p\u011bn\u00ed. Tato hypot\u00e9za je zvl\u00e1\u0161\u0165 d\u016fle\u017eit\u00e1 pro v\u00fdzkum modr\u00fdch velryb, proto\u017ee vzhledem k jejich specifick\u00e9mu zp\u016fsobu potravy (n\u00e1hl\u00fd skok pro polyk\u00e1n\u00ed vody) by rychlost metabolismu teoreticky m\u011bla p\u0159ekro\u010dit z\u00e1kladn\u00ed hodnoty (klidov\u00fd stav) a\u017e 50kr\u00e1t. P\u0159edpokl\u00e1d\u00e1 se, \u017ee takov\u00e9 skoky urychluj\u00ed vy\u010derp\u00e1n\u00ed kysl\u00edku a t\u00edm zkracuj\u00ed dobu pono\u0159en\u00ed.<\/p>\n

Zv\u00fd\u0161en\u00e1 srde\u010dn\u00ed frekvence a zv\u00fd\u0161en\u00e9 dod\u00e1v\u00e1n\u00ed kysl\u00edku z krve do sval\u016f b\u011bhem skoku mohou hr\u00e1t d\u016fle\u017eitou roli vzhledem k metabolick\u00fdm n\u00e1rok\u016fm b\u011bhem takov\u00e9 fyzick\u00e9 aktivity. Je tak\u00e9 nutn\u00e9 vz\u00edt v \u00favahu n\u00edzkou koncentraci myoglobinu*<\/i> (Mb) u modr\u00fdch velryb (5-10kr\u00e1t ni\u017e\u0161\u00ed ne\u017e u jin\u00fdch mo\u0159sk\u00fdch savc\u016f: 0,8 g Mb na 100 g-1 sval\u016f u modr\u00fdch velryb a 1,8-10 g Mb u jin\u00fdch mo\u0159sk\u00fdch savc\u016f.<\/p>\n

Myoglobin*<\/b> \u2014 kysl\u00edk v\u00e1zaj\u00edc\u00ed b\u00edlkovina ve svalech kostry a srdce.<\/p><\/blockquote>\n

Na z\u00e1v\u011br, fyzick\u00e1 z\u00e1t\u011b\u017e, hloubka pono\u0159en\u00ed a v\u016fl\u00ed kontrola m\u011bn\u00ed srde\u010dn\u00ed frekvenci b\u011bhem pot\u00e1p\u011bn\u00ed prost\u0159ednictv\u00edm autonomn\u00edho nervov\u00e9ho syst\u00e9mu. <\/p>\n

Dal\u0161\u00edm faktorem sni\u017euj\u00edc\u00edm srde\u010dn\u00ed frekvenci m\u016f\u017ee b\u00fdt i stla\u010den\u00ed\/roz\u0161\u00ed\u0159en\u00ed plic b\u011bhem ponoru\/vzletu.<\/p>\n

Takto je srde\u010dn\u00ed frekvence b\u011bhem ponoru a p\u0159i pobytu na povrchu p\u0159\u00edmo spojena s modely arteri\u00e1ln\u00ed hemodynamiky.<\/p>\n

\"Mal\u00e9
\nFinval<\/i><\/p>\n

D\u0159\u00edve proveden\u00fd v\u00fdzkum biomechanick\u00fdch vlastnost\u00ed a rozm\u011br\u016f st\u011bn aorty u finvala (Balaenoptera physalus<\/i>) uk\u00e1zal, \u017ee b\u011bhem ponor\u016f p\u0159i srde\u010dn\u00ed frekvenci \u226410 \u00fader\u016f\/min aorta vykazuje efekt rezervo\u00e1ru (Windkessel efekt<\/i>), kter\u00fd udr\u017euje pr\u016ftok krve b\u011bhem dlouh\u00fdch diastolick\u00fdch obdob\u00ed*<\/i> mezi srde\u010dn\u00edmi kontrakcemi a sni\u017euje pulzaci krvn\u00edho toku do tuh\u00e9 dist\u00e1ln\u00ed aorty.<\/p>\n

Diastola*<\/b> (diastolick\u00e9 obdob\u00ed) \u2014 obdob\u00ed uvoln\u011bn\u00ed srdce mezi kontrakcemi.<\/p><\/blockquote>\n

V\u0161echny v\u00fd\u0161e uveden\u00e9 hypot\u00e9zy, teorie a dedukce by m\u011bly m\u00edt hmatateln\u00e9 d\u016fkazy, tedy b\u00fdt potvrzeny nebo vyvr\u00e1ceny v praxi. K tomu v\u0161ak je pot\u0159eba prov\u00e9st elektrokardiografii voln\u011b se pohybuj\u00edc\u00edmu modr\u00e9mu velryb\u011b. Prost\u00e9 metody zde nebudou fungovat, proto v\u011bdci vytvo\u0159ili sv\u016fj p\u0159\u00edstroj pro elektrokardiografii.<\/p>\n

\r\n \"P\u0159ehr\u00e1t\r\n
<\/div>\r\n <\/div><\/center>
\nVideo, ve kter\u00e9m v\u00fdzkumn\u00edci stru\u010dn\u011b hovo\u0159\u00ed o sv\u00e9 pr\u00e1ci.<\/i><\/p>\n

EKG plejtvana byla zaznamen\u00e1na pomoc\u00ed na m\u00edru vyroben\u00e9ho EKG registr\u00e1toru, kter\u00fd byl zabudov\u00e1n do speci\u00e1ln\u00ed kapsle se 4 p\u0159\u00edsavkami. Povrchov\u00e9 EKG elektrody byly integrov\u00e1ny do dvou z t\u011bchto p\u0159\u00edsavek. V\u00fdzkumn\u00edci se vydali na \u010dlunu do z\u00e1livu Monterey (Tich\u00fd oce\u00e1n, pobl\u00ed\u017e Kalifornie). Kdy\u017e se v\u011bdc\u016fm kone\u010dn\u011b poda\u0159ilo potkat modr\u00e9ho plejtvana, kter\u00fd vyplul na povrch, p\u0159ipevnili k jeho t\u011blu (vedle lev\u00e9 ploutve) EKG registr\u00e1tor. Podle d\u0159\u00edve shrom\u00e1\u017ed\u011bn\u00fdch \u00fadaj\u016f je tento plejtv\u00e1n samcem ve v\u011bku 15 let. Je d\u016fle\u017eit\u00e9 poznamenat, \u017ee toto za\u0159\u00edzen\u00ed je neinvazivn\u00ed, co\u017e znamen\u00e1, \u017ee nevy\u017eaduje zav\u00e1d\u011bn\u00ed jak\u00fdchkoli senzor\u016f nebo elektrod do k\u016f\u017ee zv\u00ed\u0159ete. Pro plejtvana je tedy tento postup naprosto bezbolestn\u00fd a s minim\u00e1ln\u00edm stresem z kontaktu s lidmi, co\u017e je rovn\u011b\u017e velmi d\u016fle\u017eit\u00e9, vzhledem k tomu, \u017ee byly zachyceny \u00fadaje o srde\u010dn\u00edm tepu, kter\u00e9 by mohly b\u00fdt zkresleny vlivem stresu. V d\u016fsledku toho byla z\u00edsk\u00e1na 8,5 hodinov\u00e1 EKG nahr\u00e1vka, podle kter\u00e9 byli v\u011bdci schopni vypracovat profil srde\u010dn\u00edho rytmu (viz obr\u00e1zek n\u00ed\u017ee).<\/p>\n

\"Mal\u00e9
\nObr\u00e1zek \u010d. 1: profil srde\u010dn\u00edho rytmu modr\u00e9ho plejtvana.<\/i><\/p>\n

Tvar EKG sign\u00e1lu byl podobn\u00fd tomu, kter\u00fd byl zaznamen\u00e1n u men\u0161\u00edch kytovc\u016f v zajet\u00ed pomoc\u00ed stejn\u00e9ho za\u0159\u00edzen\u00ed. Chov\u00e1n\u00ed plejtvana b\u011bhem hled\u00e1n\u00ed potravy bylo zcela b\u011b\u017en\u00e9 pro jeho druh: pot\u00e1p\u011bn\u00ed po dobu 16,5 minuty do hloubky 184 m a povrchov\u00e9 intervaly od 1 do 4 minut.<\/p>\n

Profil srde\u010dn\u00edho rytmu, v souladu se srde\u010dn\u011b-c\u00e9vn\u00ed odpov\u011bd\u00ed na pot\u00e1p\u011bn\u00ed, uk\u00e1zal, \u017ee frekvence srde\u010dn\u00edch tep\u016f od 4 do 8 \u00fader\u016f za minutu dominovala v doln\u00ed f\u00e1zi pot\u00e1p\u011bn\u00ed p\u0159i hled\u00e1n\u00ed potravy, bez ohledu na d\u00e9lku pot\u00e1p\u011bn\u00ed nebo maxim\u00e1ln\u00ed hloubku. Frekvence srde\u010dn\u00edch tep\u016f p\u0159i pot\u00e1p\u011bn\u00ed (vypo\u010d\u00edt\u00e1no za celou dobu pot\u00e1p\u011bn\u00ed) a minim\u00e1ln\u00ed okam\u017eit\u00e1 frekvence srde\u010dn\u00edch tep\u016f b\u011bhem pot\u00e1p\u011bn\u00ed klesaly s d\u00e9lkou pot\u00e1p\u011bn\u00ed, zat\u00edmco maxim\u00e1ln\u00ed povrchov\u00e1 frekvence srde\u010dn\u00edch tep\u016f po pot\u00e1p\u011bn\u00ed se zvy\u0161ovala s d\u00e9lkou pot\u00e1p\u011bn\u00ed. Jin\u00fdmi slovy, \u010d\u00edm d\u00e9le byl plejtv\u00e1n pod vodou, t\u00edm pomaleji mu bije srdce b\u011bhem pot\u00e1p\u011bn\u00ed a t\u00edm rychleji po vyplut\u00ed.<\/p>\n

Podle allometrick\u00fdch rovnic u savc\u016f, velryba s hmotnost\u00ed 70000 kg m\u00e1 srdce v\u00e1\u017e\u00edc\u00ed 319 kg a jej\u00ed \u00faderov\u00fd objem (objem krve vypu\u0161t\u011bn\u00fd p\u0159i jednom \u00faderu) je p\u0159ibli\u017en\u011b 80 l, tud\u00ed\u017e by m\u011bla m\u00edt klidovou srde\u010dn\u00ed frekvenci 15 \u00fader\u016f\/min.<\/p>\n

B\u011bhem doln\u00edch f\u00e1z\u00ed pot\u00e1p\u011bn\u00ed byla okam\u017eit\u00e1 srde\u010dn\u00ed frekvence od 1\/3 do 1\/2 p\u0159edpokl\u00e1dan\u00e9 klidov\u00e9 srde\u010dn\u00ed frekvence. Nicm\u00e9n\u011b, rytmus srdce se zvy\u0161oval ve f\u00e1zi vyno\u0159en\u00ed. V povrchov\u00fdch intervalech byla srde\u010dn\u00ed frekvence p\u0159ibli\u017en\u011b dvakr\u00e1t vy\u0161\u0161\u00ed ne\u017e p\u0159edpokl\u00e1dan\u00e1 klidov\u00e1 srde\u010dn\u00ed frekvence a p\u0159ev\u00e1\u017en\u011b se pohybovala od 30 do 37 \u00fader\u016f za minutu po hlubok\u00fdch ponorech (> 125 metr\u016f) a od 20 do 30 \u00fader\u016f za minutu po m\u011blk\u00fdch ponorech.<\/p>\n

Tato pozorov\u00e1n\u00ed mohou nazna\u010dovat, \u017ee zrychlen\u00ed srde\u010dn\u00edch kontrakc\u00ed je nezbytn\u00e9 pro dosa\u017een\u00ed po\u017eadovan\u00e9 v\u00fdm\u011bny dechov\u00fdch plyn\u016f a reperfuzi (obnoven\u00ed tok krve) tk\u00e1n\u00ed mezi hlubok\u00fdmi ponory.<\/p>\n

M\u011blk\u00e9 kr\u00e1tkodob\u00e9 no\u010dn\u00ed ponory byly spojeny s odpo\u010dinkem a proto v\u00edce charakteristick\u00e9 pro m\u00e9n\u011b aktivn\u00ed stav. Typick\u00e9 srde\u010dn\u00ed frekvence pozorovan\u00e9 b\u011bhem 5 minutov\u00e9ho no\u010dn\u00edho ponoru (8 \u00fader\u016f za minutu) a prov\u00e1zej\u00edc\u00edho 2 minutov\u00e9ho povrchov\u00e9ho intervalu (25 \u00fader\u016f za minutu) mohou celkov\u011b v\u00e9st k tomu, \u017ee rytmus srdce bude kolem 13 \u00fader\u016f za minutu. Tato cifra, jak vid\u00edme, je p\u0159ekvapiv\u011b bl\u00edzk\u00e1 v\u00fdpo\u010dtov\u00fdm predikc\u00edm allometrick\u00fdch model\u016f.<\/p>\n

D\u00e1le v\u011bdci vytvo\u0159ili profily srde\u010dn\u00ed frekvence, hloubky a relativn\u00edho objemu plic pro 4 jednotliv\u00e9 ponory, jejich\u017e anal\u00fdza umo\u017enila prozkoumat potencion\u00e1ln\u00ed vliv fyzick\u00e9 aktivity a hloubky na regulaci srde\u010dn\u00edho rytmu.<\/p>\n

\"Mal\u00e9
\nObr\u00e1zek \u010d. 2: profily srde\u010dn\u00ed frekvence, hloubky a relativn\u00edho objemu plic pro 4 jednotliv\u00e9 ponory.<\/i><\/p>\n

B\u011bhem konzumace potravy ve velk\u00fdch hloubk\u00e1ch velryba prov\u00e1d\u00ed specifick\u00fd man\u00e9vr, kdy n\u00e1hle otev\u00edr\u00e1 svou tlamu, aby nas\u00e1la vodu s planktonem, a pot\u00e9 filtruje potravu. Bylo zaznamen\u00e1no, \u017ee \u010detnost srde\u010dn\u00edch tep\u016f b\u011bhem nas\u00e1v\u00e1n\u00ed vody je 2,5kr\u00e1t vy\u0161\u0161\u00ed ne\u017e b\u011bhem filtrace. To jasn\u011b ukazuje na z\u00e1vislost rytmu srdce na fyzick\u00e9 z\u00e1t\u011b\u017ei.<\/p>\n

Co se t\u00fd\u010de plic, jejich vliv na srde\u010dn\u00ed rytmus je vysoce nepravd\u011bpodobn\u00fd, proto\u017ee nebyly pozorov\u00e1ny \u017e\u00e1dn\u00e9 zna\u010dn\u00e9 zm\u011bny relativn\u00edho objemu plic b\u011bhem zkouman\u00fdch ponor\u016f. <\/p>\n

V ni\u017e\u0161\u00edch f\u00e1z\u00edch m\u011blk\u00fdch ponor\u016f bylo kr\u00e1tkodob\u00e9 zv\u00fd\u0161en\u00ed srde\u010dn\u00edch tep\u016f spojeno pr\u00e1v\u011b se zm\u011bnami relativn\u00edho objemu plic a mohlo b\u00fdt zp\u016fsobeno aktivac\u00ed receptoru pro plicn\u00ed rozta\u017een\u00ed.<\/p>\n

Shrnuj\u00edc v\u00fd\u0161e uveden\u00e9 pozorov\u00e1n\u00ed, v\u011bdci dosp\u011bli k z\u00e1v\u011bru, \u017ee b\u011bhem krmen\u00ed ve velk\u00fdch hloubk\u00e1ch doch\u00e1z\u00ed k kr\u00e1tkodob\u00e9mu zv\u00fd\u0161en\u00ed srde\u010dn\u00ed frekvence o 2,5kr\u00e1t. Nicm\u00e9n\u011b pr\u016fm\u011brn\u00e1 maxim\u00e1ln\u00ed srde\u010dn\u00ed frekvence b\u011bhem man\u00e9vr\u016f p\u0159i krmen\u00ed st\u00e1le \u010dinila pouze polovinu p\u0159edpokl\u00e1dan\u00e9 hodnoty v klidu. Tato data podporuj\u00ed hypot\u00e9zu, \u017ee pru\u017en\u00e9 oblouky aorty velk\u00fdch velryb realizuj\u00ed efekt z\u00e1sobn\u00edku b\u011bhem pomal\u00e9ho srde\u010dn\u00edho rytmu b\u011bhem ponoru. Krom\u011b toho rozsah vy\u0161\u0161\u00edch srde\u010dn\u00edch tep\u016f po ponoru potvrdil hypot\u00e9zu, \u017ee odpor aorty a z\u00e1t\u011b\u017e srdce klesaj\u00ed b\u011bhem povrchov\u00e9ho intervalu v d\u016fsledku destruktivn\u00edho z\u00e1sahu vych\u00e1zej\u00edc\u00edch a odr\u00e1\u017een\u00fdch tlakov\u00fdch vln v aort\u011b. <\/p>\n

Silnou bradykardii, kterou pozorovali v\u011bdci, lze pova\u017eovat za ne\u010dekan\u00fd v\u00fdsledek v\u00fdzkumu, vzhledem k obrovsk\u00e9 n\u00e1maze velryby p\u0159i man\u00e9vru nas\u00e1v\u00e1n\u00ed vody s planktonem. Nicm\u00e9n\u011b metabolick\u00e9 n\u00e1klady tohoto man\u00e9vru nemus\u00ed odpov\u00eddat srde\u010dn\u00ed frekvenci nebo konvek\u010dn\u00edmu transportu kysl\u00edku \u010d\u00e1ste\u010dn\u011b kv\u016fli kr\u00e1tk\u00e9 dob\u011b krmen\u00ed a mo\u017en\u00e9 aktivaci glykolytick\u00fdch, rychle kontrahuj\u00edc\u00edch svalov\u00fdch vl\u00e1ken.<\/p>\n

B\u011bhem v\u00fdpadu se mod\u0159\u00ed velryby rozj\u00ed\u017ed\u011bj\u00ed na vysokou rychlost a nas\u00e1vaj\u00ed objem vody, kter\u00fd m\u016f\u017ee b\u00fdt v\u011bt\u0161\u00ed ne\u017e jejich vlastn\u00ed t\u011blo. V\u011bdci se domn\u00edvaj\u00ed, \u017ee vysok\u00fd odpor a energie pot\u0159ebn\u00e1 k man\u00e9vrov\u00e1n\u00ed rychle vy\u010derp\u00e1vaj\u00ed celkov\u00e9 z\u00e1soby kysl\u00edku v organismu, \u010d\u00edm\u017e omezuj\u00ed dobu ponoru. Mechanick\u00e1 s\u00edla pot\u0159ebn\u00e1 k nas\u00e1v\u00e1n\u00ed velk\u00e9ho objemu vody pravd\u011bpodobn\u011b mnohon\u00e1sobn\u011b p\u0159evy\u0161uje aerobn\u00ed metabolickou s\u00edlu. Pr\u00e1v\u011b proto b\u011bhem takov\u00fdch man\u00e9vr\u016f frekvence srde\u010dn\u00edho tepu sice vzr\u016fst\u00e1, ale na velmi kr\u00e1tkou dobu.<\/p>\n

Pro podrobn\u011bj\u0161\u00ed sezn\u00e1men\u00ed se s nuancemi v\u00fdzkumu doporu\u010duji nahl\u00e9dnout do zpr\u00e1vy v\u011bdc\u016f<\/a><\/noindex>.<\/p>\n

Epilog<\/h3>\n

\nJedn\u00edm z nejd\u016fle\u017eit\u011bj\u0161\u00edch zji\u0161t\u011bn\u00ed je, \u017ee pro v\u00fdm\u011bnu plyn\u016f a reperfuzi b\u011bhem kr\u00e1tk\u00fdch povrchov\u00fdch interval\u016f pot\u0159ebuj\u00ed mod\u0159\u00ed velryby t\u00e9m\u011b\u0159 maxim\u00e1ln\u00ed srde\u010dn\u00ed frekvenci, bez ohledu na charakter vy\u010derp\u00e1n\u00ed z\u00e1sob kysl\u00edku v krvi a svalech b\u011bhem ponor\u016f. Pokud vezmeme v \u00favahu, \u017ee v\u011bt\u0161\u00ed jedinci modr\u00fdch velryb mus\u00ed vynalo\u017eit v\u00edce n\u00e1mahy, aby z\u00edskali potravu za krat\u0161\u00ed \u010das (podle alometrick\u00fdch hypot\u00e9z), nevyhnuteln\u011b \u010del\u00ed n\u011bkolika fyziologick\u00fdm omezen\u00edm jak b\u011bhem ponoru, tak b\u011bhem povrchov\u00e9ho intervalu. To znamen\u00e1, \u017ee evolu\u010dn\u011b je velikost jejich t\u011bla omezen\u00e1, proto\u017ee by-li v\u011bt\u0161\u00ed, proces z\u00edsk\u00e1v\u00e1n\u00ed potravy by byl velmi n\u00e1kladn\u00fd a nekompenzoval by se z\u00edskanou potravou. Sami badatel\u00e9 se domn\u00edvaj\u00ed, \u017ee srdce modr\u00e9 velryby pracuje na hranici sv\u00fdch mo\u017enost\u00ed. <\/p>\n

V budoucnu v\u011bdci pl\u00e1nuj\u00ed roz\u0161\u00ed\u0159it mo\u017enosti sv\u00e9ho za\u0159\u00edzen\u00ed, v\u010detn\u011b p\u0159id\u00e1n\u00ed akcelerometru, aby l\u00e9pe porozum\u011bli vlivu r\u016fzn\u00fdch fyzick\u00fdch aktivit na srde\u010dn\u00ed rytmus. Tak\u00e9 pl\u00e1nuj\u00ed aplikovat sv\u016fj EKG senzor na jin\u00e9 mo\u0159sk\u00e9 obyvatelstvo. <\/p>\n

Jak uk\u00e1zal tento v\u00fdzkum, b\u00fdt nejv\u011bt\u0161\u00edm tvorem s nejv\u011bt\u0161\u00edm srdcem nen\u00ed tak snadn\u00e9. Nicm\u00e9n\u011b, a\u0165 u\u017e maj\u00ed mo\u0159sk\u00e9 obyvatel\u00e9 jakoukoli velikost nebo jakoukoli dietu, mus\u00edme ch\u00e1pat, \u017ee sloupec vody, kter\u00fd lid\u00e9 pou\u017e\u00edvaj\u00ed k rybolovu, t\u011b\u017eb\u011b a p\u0159eprav\u011b, z\u016fst\u00e1v\u00e1 jejich domovem. My jsme pouze host\u00e9, a proto se mus\u00edme chovat odpov\u00eddaj\u00edc\u00edm zp\u016fsobem.<\/p>\n

P\u00e1te\u010dn\u00ed off-topic:<\/b>

\r\n \"P\u0159ehr\u00e1t\r\n
<\/div>\r\n <\/div><\/center>
\nVz\u00e1cn\u00e9 z\u00e1b\u011bry, na nich\u017e modr\u00e1 velryba demonstruje kapacitu sv\u00e9ho \u00fast.<\/i><\/p>\n

\r\n \"P\u0159ehr\u00e1t\r\n
<\/div>\r\n <\/div><\/center>
\nDal\u0161\u00edm obrem mo\u0159\u00ed je vorva\u0148. V tomto videu v\u011bdci pomoc\u00ed d\u00e1lkov\u011b \u0159\u00edzen\u00e9ho ROV Hercules zaznamenali zv\u011bdav\u00e9ho vorvana v hloubce 598 metr\u016f.<\/i><\/p>\n

D\u011bkuji za pozornost, z\u016fsta\u0148te zv\u011bdav\u00ed a p\u0159eji v\u0161em skv\u011bl\u00e9 v\u00edkendy, kamar\u00e1di! \ud83d\ude42<\/p>\n

D\u011bkujeme, \u017ee s n\u00e1mi z\u016fst\u00e1v\u00e1te. L\u00edb\u00ed se v\u00e1m na\u0161e \u010dl\u00e1nky? Chcete vid\u011bt v\u00edce zaj\u00edmav\u00fdch materi\u00e1l\u016f? Podpo\u0159te n\u00e1s objedn\u00e1vkou nebo doporu\u010den\u00edm zn\u00e1m\u00fdm, cloudov\u00e9 VPS pro v\u00fdvoj\u00e1\u0159e od 4,99 $<\/a><\/noindex>, 30 % sleva pro u\u017eivatele Habra na jedine\u010dn\u00fd analog entry-level server\u016f, kter\u00fd jsme pro v\u00e1s vymysleli:<\/b> Ve\u0161ker\u00e1 pravda o VPS (KVM) E5-2650 v4 (6 jader) 10GB DDR4 240GB SSD 1Gbps od 20 $ nebo jak spr\u00e1vn\u011b rozd\u011blit server?<\/a><\/noindex> (k dispozici varianty s RAID1 a RAID10, a\u017e 24 jader a a\u017e 40GB DDR4).<\/p>\n

Dell R730xd za polovinu ceny?<\/b> Jen u n\u00e1s 2 x Intel TetraDeca-Core Xeon 2x E5-2697v3 2.6GHz 14C 64GB DDR4 4x960GB SSD 1Gbps 100 TB od 199 $<\/a><\/noindex> v Nizozemsku! Dell R420 \u2014 2x E5-2430 2.2GHz 6C 128GB DDR3 2x960GB SSD 1Gbps 100TB \u2014 od 99 $!<\/b><\/b> \u010ct\u011bte o tom Jak postavit infrastrukturu podnikov\u00e9 t\u0159\u00eddy s pou\u017eit\u00edm server\u016f Dell R730xd E5-2650 v4 v hodnot\u011b 9000 eur za pakatel?<\/a><\/noindex>
\n
Zdroj: habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

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