GIẢI PHẪU SINH LÝ T.HOAN

GII PHU SINH L H TUN HON

Gii phu-Sinh l timc im cu to tim

Tim nm trong trung tht, trn c honh, sau xng c, gia hai phi, hi lch sang tri. Hnh th ngoi: hnh thp ba mt, mt y, mt nh. nh tim (mm tim) nm chch sang tri, xung di. y tim pha trn, quay ra sau ng vi mt sau hai tm nh. Cc mt tim: mt trc (sau xng c), mt honh v mt phi (phi tri).


Hnh th trong: hai tm nh v hai tm tht. Hai tm nh ngn bi vch gian nh. Thnh tm nh mng hn tm tht. L nh tht thng tm nh vi tm tht v c van nh tht y, van hai l bn tri, van ba l bn phi. Cc tnh mch vo tm nh. Hai tm tht ngn bi vch gian tht, cu to bi lp c dy. Cc ng mch ln i ra t tm tht c cc van t chim ngn cch.


Thnh tim: ngoi tm mc, c tim, ni tm mc. Ngoi tm mc l ti kn gm hai bao: bao si v bao thanh mc gm l thnh v l tng. Gia hai l l khoang o.

Gii phu-Sinh l timc im cu to timo

Thnh tim: C tim to thnh mng li, mng si c tim c on ha vo nhau to cu dn truyn xung ng lm tim hot ng nh mt hp bo duy nht. Trong c tim c cc si c mang tnh thn kinh pht xung t ng gip c co bp nhp nhng. Ni tm mc l mng mng ph ln ton b mt trong bung tim.


H thng dn truyn ca tim: Nt xoang nh (Keith-Flack) nm trong thnh tm nh phi. Nt nh tht (Tawara) nm di lp ni mc tm nh phi.


H thng dn truyn ca tim: B His tch ra t nt nh tht, nm mt phi vch nh tht v i dc vch ny, chia hai nhnh vo hai tm tht ri ta thnh mng li Purkinje. Mch v thn kinh tim: M vnh, h thng dn truyn ca tim, TK thc vt.

Tnh t ng ca tim

Nt Keith Flack (nt xoang) Nt Tawara B His li Pourkinje (V)

Gii phu-Sinh l timCc tnh cht sinh l ca c tim

Tnh hng phn: Tun theo nh lut khng hoc tt c: khi kch thch cha ti ngng cha co, kch thch ti ngng co vi bin ti a v gi n nh mc ny.


Tnh hng phn: C tim hng phn nh s bin i in th mng: bnh thng mt ngoi mng (+), mt trong (-); khi hng phn: Na+ vo trong mt ngoi mng (-), mt trong (+) t mc ti a trong vi phn ngn giy, duy tr 0,2 0,3 giy ri kt thc t ngt tr v bnh thng.


Tnh dn truyn: Tc dn truyn bng 1/10 si c xng, 1/250 si TK. Tng ng 0,02 4 m/s. S dn truyn chm v khc nhau tng phn ca tim do s lin quan vi chc nng to nhp co bp v bm mu ca tim. Tm nh co tm tht co.


Tnh tr c chu k: G tr tuyt i, khong 0,27s khi tim ang co, c tim khng p ng vi bt k kch thch no. G tr tng i, khong 0,03s lc t bo ti cc tr v bnh thng, c tim ch p ng vi kch thch cao hn ngng ngoi tm thu.


Tnh tr c chu k: G hng vng, khong 0,03s kh nng hng phn tng hn mc bnh thng. G hi phc hon ton. Sau ti cc, mng t bo tr li phn cc nh bnh thng.


Tnh nhp iu: Bnh thng tim p theo nhp nt xoang khong 70 nhp/pht. Nt nh tht pht xung ng 40 60 nhp/pht. B His: 30 40 nhp/pht. Mng Purkinje: 20 40 nhp/pht.

Gii phu-Sinh l timChu k hot ng ca tim

Trong mt chu k tim, mu c bm t tm tht ra cc M khi tm tht co v dc ht t cc TM v tim khi tim gin. S hot ng ca tim trong mt chu k gn lin vi s ng m cc van tim v s bin i p lc trong cc bung tim. Tim p khong 75 nhp/pht, thi gian mt chu k 0,8s gm hai th: tm thu v tm trng.


Th tm thu: Tm nh thu (0,1s) lm p lc tng cao hn tm tht van nh tht m hon ton y nt lng mu cn li xung tm tht (3/4 lng mu do lc ht ca tm tht). Sau tm nh dn trong sut thi gian cn li ca chu k tim, p sut nh gim dn n mc c tr s m.


Th tm thu: Tm tht thu (0,3s) gm 2 thi k: + Thi k tng p: p sut tht cao hn nh ng van nh tht, nhng van t chim cha m; p sut tht tng dn m van t chim. + Thi k tng mu: mu ra khi tht qua M ch v M phi. Khi tm tht bt u dn, p sut gim thp ng van t chim..


Th tm trng: 0,4s. C nh v tht u ngh, gm ba thi k: + Dn ng tch: tht dn nhng th tch khng thay i, p sut gim dn thp hn nh. Cng lc nh dn lm mu t cc TM v p sut nh tng dn h m van nh tht mu chy vo tht. + y mu nhanh:mu t nh chy nhanh xung tht. + y mu chm, lc ny lng mu t nh xung tht. n y bt u nh thu.

Gii phu-Sinh l timLu lng ca tim

Lu lng tim l lng mu tim bm vo M trong mt pht, gi l th tch/pht. Bnh thng khong 5 l/pht. Th tch tm thu l lng mu mt tm tht y ra khi tim trong mt ln tm tht thu. Bnh thng 70 ml.

Gii phu-Sinh l timiu ha hot ng ca tim

Khi ngh, tim bm i 4 6 lt mu mi pht. iu ha do cc yu t bn ngoi tim: - C ch TK: h TKTV trong h ph giao cm c ch nt xoang, nt nh tht lm gim mi hot ng ca c tim; h giao cm tc dng ngc li. C ch TK thng qua cc cht trung gian ha hc l acetylcholin v noradrenalin.


iu ha do cc yu t bn ngoi tim: o Cc phn x iu ha tim: + PX gim p: khi p sut quai M ch v xoang M cnh tng kch thch th th ti ch kch thch dy X tim p chm, HA gim. + PX Gollz: nh mnh vng thng v kch thch dy X tim ngng p.


iu ha do cc yu t bn ngoi tim: o Cc phn x iu ha tim: + PX tim tim: khi mu dn v tim nhiu th tch bung tim tng kch thch th th gc TM ch c ch dy X tng sc co bp c tim y mu ra khi tim. + PX mt tim: p mnh vo hai nhn cu kch thch dy V kch thch dy X tim p chm.


iu ha do cc yu t bn ngoi tim: - C ch th dch: Hormon ty thng thn, tuyn gip lm tim p nhanh. Ca2+ tng trng lc c tim tim p nhanh. K+ ngc li. Nng kh carbonic/mu tng v oxy/mu gim tim p nhanh v ngc li. Khi thn nhit tng tim p nhanh v ngc li..


iu ha ti tim: C ch Frank Starling: mu v tht nhiu lm c tim di ra khin cc si actin v myosin gi ln nhau v tr thun li to lc co c. Nh vy mu cng v nhiu th c tim co bp cng khe.

2.Gii phu-Sinh l ng mchc im cu to ng mch

Thnh M dy, gm ba lp: + Lp ngoi: to bi m lin kt cha nhiu b si to keo lm thnh dai, bn kh v. C nhiu u dy TKTV trong lp ny. + Lp gia: gm cc si c trn, si lin kt v si n hi. Lp ny ngn cch lp ngoi bi mng ngn chun ngoi. + Lp trong: t bo ni mc nhn, trong cng l lp di ni m c kh nng ti to v pht trin. Lp ny ngn cch lp gia bi mng ngn chun trong

2.Gii phu-Sinh l ng mchHA M v cc yu t nh hng n HA M

Mu chy trong lng mch do hai yu t quyt nh: s chnh lch p sut gia hai u on mch (do s co bp ca c tim to nn) v sc cn mch mu. Trong lc y mu ca tim thng sc cn thnh mch lm mu chy c trong M vi p sut nht nh gi l HA.


HA ti a (HA tm thu) l tr s HA M cao nht trong chu k tim; phn nh lc co tm tht. HA ti thiu (HA tm trng) l tr s HA thp nht o c trong th tm trng; phn nh trng lc thnh mch. HA max HA min = 40 mmHg. Nu # 20 mmHg HA kt.


Cc yu t nh hng ti HA: Tim: lc co bp ca c tim, nhp tim. Mu: qunh, th tch mu. Mch mu: ng knh, trng lc mch. Yu t khc: tui, ch n, vn ng.

2.Gii phu-Sinh l ng mchiu ha tun hon ng mch

C ch TK: H giao cm: trung tm vn mch hnh-cu no pht xung theo cc dy co mch co cc M nh v tiu M tng HA. Khi xung ng n tim tng tn s tim, tng co bp c tim. Cc si dy dn mch ( phn trc vng di i) gim trng lc thnh mch, tng lu lng mu ti c.


C ch TK: H ph giao cm: dy X lm dn mch ni tng. Cc si ph giao cm gy dn mch ngoi vi, nhng gy co mch no, mch vnh; cc si i trong dy cng lm dn mch cc tng trong h chu.


C ch TK: Cc PX iu ha HA: o Cc PX bt ngun t cc th th nm trong h tun hon: + PX cm th p: di cung M ch, xoang M cnh (PX iu ha tim). + PX cm th ha hc: di cung M ch, xoang M cnh (PX iu ha tim) lin quan nng cc kh carbonic, oxy v H+ trong mu. + PX cm th th tch: bung tim.


C ch TK: Cc PX iu ha HA: Cc PX bt ngun t cc th th nm ngoi h tun hon: + Kch thch gy au HA gim mnh; nu kch thch yu HA tng. + Kch thch nhit dn mch ti ch, co mch chung HA tng. Kch thch lnh th ngc li.


C ch th dch: Cc yu t co mch: + Adrenalin v noradrenalin: h giao cm b kch thch ty thng thn tit ra co mch tng HA.


C ch th dch: Cc yu t co mch: + H renin-angiotensin: mu n thn gim thn tit renin lm angiotensin I chuyn thnh angiotensin II co mch (c M v TM), tng ti hp thu Na+, nc tng th tch ngoi bo, tng HA.


C ch th dch: Cc yu t co mch: + Vasopressin: HA gim vng di i tng tit vasopressin co mch, tng ti hp thu nc ng thn tng HA.


C ch th dch: Cc yu t dn mch (v tng tnh thm mao mch gy thot huyt tng): gm cc cht trung gian ha hc, ch yu trong qu trnh vim: bradykinin, histamin, prostaglandin, Cc yu t khc: Ca2+ tng co mch, co c trn. Gy dn mch khi tng K+, Mg2+, CO2 (O2 gim).

3.Gii phu-Sinh l tnh mchc im cu to tnh mch

Cu to thnh TM cng ba lp nhng lp o gia mng, t c n hi km, d xp. Thnh phn to keo pht trin mnh, c nhiu mch mu nui dng. Lng TM nm di tim c nhiu van. H TM dn mu v tim, cha mu, y mu gp phn iu ha lu lng tim.

3.Gii phu-Sinh l tnh mchNguyn nhn ca tun hon tnh mch

Sc bm ca c tim: cui h M 60 70 mmHg mao mch 17 35 mmHg u TM 10 15 mmHg tm nh phi (-). Sc ht ca tim: Th tm thu sn van nh tht h xung pha mm tim bung nh dn gim p sut nh ht mu TM v. Th tm trng p sut trong tim gim to sc ht t TM v nh, v t nh xung tht.

3.Gii phu-Sinh l tnh mchNguyn nhn ca tun hon tnh mch

Sc ht ca lng ngc. nh hng ca c v van TM: khi co, c xng s p vo TM y mu v tim. nh hng ca nhp p M: khi p s p vo TM. nh hng ca trng lc: cng xa tim p lc mu TM cng ln mu chy v tim t ni c p lc cao n ni thp hn.

3.Gii phu-Sinh l tnh mchiu ha tun hon tnh mch

Gy co TM: lnh, adrenalin,, pilocacpin, nicotin, Gy dn TM: nng, nng carbonic tng, oxy gim, cocain, cefein,

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GIẢI PHẪU SINH LÝ T.HOAN