Peb lub siab yog cov leeg nqaij uas muaj qhov sib txuas ua ke tag nrho. Nyob rau hauv nws yog ib tug complex system ntawm cov hlwb tshwj xeeb (pacemakers), uas muaj ib tug ntau theem system rau saib xyuas kev ua hauj lwm. Nws kuj suav nrog Purkinje fibers. Lawv nyob rau hauv myocardium ntawm lub ventricles thiab yog lub luag hauj lwm rau lawv synchronous contraction.
General anatomy of the conduction system
Lub cev kev coj ua ntawm lub siab tau muab faib los ntawm anatomists ua plaub ntu. Lub sinus-atrial (sinoatrial) node belongs rau thawj feem. Nws yog kev sib xyaw ua ke ntawm peb pawg ntawm cov hlwb uas tsim cov impulses ntawm ib zaus ntawm yim caum mus rau ib puas thiab nees nkaum zaug hauv ib feeb. Lub plawv dhia no tso cai rau koj kom tswj tau cov ntshav txaus hauv lub cev, nws saturation nrog oxygen thiab metabolic rate.
Yog vim li cas tus thawj pacemaker tsis tuaj yeem ua nws txoj haujlwm, lub atrioventricular (atrioventricular) ntawm qhov kev ua si. Nws yog nyob rau ntawm ciam teb ntawm lub chambers ntawm lub plawv nyob rau hauv nruab nrab septum. nwsQhov sib txuam ntawm cov hlwb teeb tsa qhov zaus ntawm kev cog lus nyob rau hauv thaj tsam ntawm rau caum txog rau yim caum tus neeg ntaus thiab suav hais tias yog tus txiav txim thib ob.
theem tom ntej ntawm cov txheej txheem conduction yog cov pob khoom ntawm Nws thiab Purkinje fibers. Lawv nyob rau hauv lub interventricular septum thiab braid lub apex ntawm lub plawv. Qhov no ua rau nws muaj peev xwm propagate hluav taws xob impulses sai sai los ntawm ventricular myocardium. Tus nqi tiam nws txawv ntawm plaub caug mus rau rau caum zaus ib feeb.
khoom ntshav
Ib feem ntawm cov txheej txheem kev coj ua uas nyob hauv atria tau txais cov khoom noj los ntawm cov khoom sib cais, cais los ntawm cov seem ntawm myocardium. Lub sinoatrial node yog pub los ntawm ib los yog ob txoj hlab ntsha me me uas khiav los ntawm cov phab ntsa ntawm lub plawv. Lub peculiarity yog nyob rau hauv lub xub ntiag ntawm ib tug disproportionately cov hlab ntsha loj uas dhau los ntawm nruab nrab ntawm cov node. Qhov no yog ib ceg ntawm txoj cai coronary artery. Nws, nyob rau hauv lem, muab ntau ceg me me uas tsim ib tug ntom arterial-venous network nyob rau hauv lub cheeb tsam ntawm cov ntaub so ntswg atrial.
Cov pob khoom ntawm Nws thiab Purkinje fibers kuj tau txais kev noj haus los ntawm cov ceg ntawm txoj hlab ntsha sab xis (interventricular artery) lossis ncaj qha los ntawm nws tus kheej. Qee zaum, ntshav tuaj yeem nkag mus rau cov qauv no los ntawm cov hlab ntsha circumflex. Ntawm no, ib yam nkaus, lub network ntom ntom ntawm capillaries yog tsim, uas nruj nreem braid lub cardiomyocytes.
Cells ntawm thawj hom
Qhov sib txawv ntawm cov hlwb uas ua rau lub cev ua haujlwm yog vim qhov tseeb tias lawv ua haujlwm sib txawv. Muaj peb hom cell.
Cov pacemakers yog P-hlwb lossis cov hlwb ntawm thawj hom. Morphologically, cov no yog cov leeg nqaij me me nrog lub nucleus loj thiab ntau cov txheej txheem ntev intertwined nrog ib leeg. Ob peb lub hlwb uas nyob ib sab raug suav hais tias yog pawg sib koom ua ke los ntawm cov txheej txheem hauv qab daus.
Txhawm rau tsim kev sib cog lus, pob ntawm myofibrils nyob rau hauv ib puag ncig sab hauv ntawm P-hlwb. Cov ntsiab lus no nyob tsawg kawg yog ib feem peb ntawm tag nrho qhov chaw ntawm cytoplasm. Lwm cov organelles random nyob rau hauv lub cell thiab tsawg dua nyob rau hauv dog dig cardiomyocytes. Thiab cov tubules ntawm cytoskeleton, ntawm qhov tsis sib xws, nyob nruj thiab tswj cov duab ntawm cov pacemakers.
Sinoatrial node muaj cov hlwb, tab sis cov khoom seem, suav nrog Purkinje fibers (cov histology uas yuav tau piav qhia hauv qab no), muaj cov qauv sib txawv.
Cells ntawm hom thib ob
Lawv tseem hu ua transient lossis latent pacemakers. Cov duab tsis zoo, luv dua li ib txwm cardiomyocytes tab sis tuab dua, muaj ob lub nuclei, thiab muaj qhov sib sib zog nqus hauv cov phab ntsa ntawm tes. Muaj ntau cov organelles hauv cov hlwb ntau dua li hauv cytoplasm ntawm P-cells.
Cov ntawv cog lus filaments txuas ntxiv raws qhov ntev ntawm lub xov tooj ntawm tes. Lawv yog cov thicker thiab muaj ntau sarcomeres. Qhov no tso cai rau lawv los ua tus thib ob kev txiav txim pacemakers. Cov hlwb no nyob hauv lub atrioventricular node, thiab Nws cov pob khoom thiab Purkinje fibers ntawm micropreparations yog sawv cev los ntawm cov hlwb ntawm peb hom.
Cells ntawm peb hom
Histologists tau txheeb xyuas ntau hom hlwb nyob rau hauv lub davhlau ya nyob twg ntawm cov txheej txheem ntawm lub plawv. Raws li kev faib tawm ntawm no, cov hlwb ntawm hom thib peb yuav muaj cov qauv zoo sib xws nrog cov uas ua rau Purkinje fibers hauv plawv. Lawv muaj ntau voluminous piv rau lwm cov pacemakers, ntev thiab dav. Lub thickness ntawm myofibrils tsis zoo ib yam nyob rau hauv tag nrho cov seem ntawm fiber, tab sis cov sum ntawm tag nrho cov contractile ntsiab yog ntau dua nyob rau hauv ib txwm cardiomyocyte.
Tam sim no koj tuaj yeem sib piv cov hlwb ntawm hom thib peb nrog cov uas ua rau Purkinje fibers. Lub histology (ib qho kev npaj tau los ntawm cov ntaub so ntswg ntawm lub apex ntawm lub plawv) ntawm cov ntsiab lus txawv heev. Lub nucleus muaj cov duab plaub yuav luag, thiab cov fibers contractile yog qhov tsim tsis zoo, muaj ntau ceg thiab txuas rau ib leeg. Tsis tas li ntawd, lawv tsis pom meej meej raws li qhov ntev ntawm lub xov tooj ntawm tes thiab nyob rau ntawm lub sijhawm loj. Ib qho me me ntawm cov organelles uas nyob ib ncig ntawm myofibrils.
Qhov sib txawv ntawm qhov zaus ntawm cov impulses generated thiab ceev ntawm lawv cov conduction xav tau ib tug phylogenetically tsim mechanism rau synchronizing tus txheej txheem ntawm contraction nyob rau hauv tag nrho cov qhov chaw ntawm lub plawv.
Histological qhov sib txawv ntawm cov txheej txheem conduction thiab cardiomyocytes
Cells ntawm hom thib ob thiab thib peb muaj ntau glycogen thiab nws cov metabolites dua li cov cardiomyocytes. Qhov no feature yog tsim los muab ib tug txaus degree ntawm yas muaj nuj nqi thiab npog cov khoom noj khoom haus xav tau kev pab ntawm cov hlwb. Enzymes lub luag haujlwm rau glycolysis thiab glycogen synthesis muaj ntau yam haujlwmnyob rau hauv lub cell ntawm lub conducting system. Nyob rau hauv lub hlwb ua hauj lwm ntawm lub plawv, lub opposite duab yog pom. Vim tias qhov tshwj xeeb no, qhov txo qis hauv cov pa oxygen tau yooj yim dua los ntawm cov pacemakers, suav nrog Purkinje fibers. Kev npaj ntawm kev coj ua tom qab kev kho mob nrog cov tshuaj nquag ua haujlwm qhia tau hais tias muaj kev ua haujlwm siab nrog cholineserase thiab lysosomal enzymes.
