Dab tsi yog qhov tsis zoo thiab qhov txiaj ntsig zoo inotropic? Cov no yog efferent txoj kev uas mus rau lub plawv los ntawm cov chaw ntawm lub hlwb thiab ua ke nrog lawv yog lub thib peb theem ntawm kev tswj.
Discovery keeb kwm
Lub zog uas lub paj hlwb muaj nyob rau hauv lub siab tau pom thawj zaug los ntawm cov kwv tij G. thiab E. Weber xyoo 1845. Lawv pom tias vim muaj hluav taws xob stimulation ntawm cov hlab ntsha, muaj qhov txo qis hauv lub zog thiab zaus ntawm lub plawv contractions, uas yog, cov nyhuv inotropic thiab chronotropic tau pom. Nyob rau tib lub sijhawm, qhov excitability ntawm lub plawv cov leeg yuav txo qis (cov nyhuv batmotropic tsis zoo) thiab, nrog rau nws, qhov ceev uas excitation txav los ntawm myocardium thiab cov kab ke ua haujlwm (dromotropic tsis zoo).
Thawj zaug nws tau qhia tias kev chim siab ntawm cov paj hlwb puas cuam tshuam rau lub plawv, I. F. Zion hauv xyoo 1867, thiab tom qab ntawd tau kawm nws kom ntxaws ntxiv los ntawm I. P. Pavlov nyob rau hauv 1887. Cov paj hlwb sympathetic cuam tshuam rau tib thaj chaw ntawm lub plawv zoo li lub vagus, tab sis nyob rau hauv qhov kev coj. Nws manifests nws tus kheej nyob rau hauv muaj zog contraction ntawm lub atrial ventricles, nce lub plawv dhia, nce plawv excitability thiab ceev conduction ntawm excitation (zoo. Cov nyhuv inotropic, chronotropic, bathmotropic thiab dromotropic teebmeem).
Innervation ntawm lub siab
Lub plawv yog ib lub cev uas muaj zog heev. Ib tug impressive tus naj npawb ntawm receptors nyob rau hauv cov phab ntsa ntawm nws cov chav thiab nyob rau hauv lub epicardium muab lub laj thawj los xav txog nws ib tug reflexogenic cheeb tsam. Qhov tseem ceeb tshaj plaws nyob rau hauv lub teb ntawm rhiab formations ntawm lub cev yog ob hom mechanoreceptor neeg, uas yog nyob rau hauv feem ntau nyob rau hauv sab laug ventricle thiab atria: A-receptors uas teb rau cov kev hloov nyob rau hauv lub nro ntawm lub plawv phab ntsa, thiab B-receptors uas. zoo siab heev thaum lub sij hawm nws passive stretching.
Nyob rau hauv lem, cov afferent fibers txuam nrog cov receptors yog cov hlab ntsha vagus. Qhov pub dawb qhov xaus ntawm cov hlab ntsha nyob hauv qab endocardium yog cov terminals ntawm cov centripetal fibers uas ua rau cov hlab ntsha sympathetic. Nws feem ntau lees paub tias cov qauv no tau koom ncaj qha rau hauv kev txhim kho ntawm qhov mob syndrome, radiating segmentally, uas characterizes kev tawm tsam ntawm cov kab mob coronary. Cov nyhuv inotropic yog qhov txaus siab rau ntau tus.
Nyob zoo ib tsoom niam txiv kwv tij neej tsas sawv daws
Efferent innervation tshwm sim vim ob qhov kev faib ntawm ANS. Cov sympathetic preanglionic neurons koom nrog yog nyob rau hauv cov teeb meem grey nyob rau hauv lub sab sauv peb thoracic ntu nyob rau hauv tus txha caj qaum, uas yog lub lateral horns. Nyob rau hauv lem, preanglionic fibers txav mus rau cov neurons ntawm lub siab xav ganglion (superior thoracic). Cov fibers yog postganglionic ua ke nrog parasympatheticcov hlab ntsha vagus tsim cov hlab ntsha sab saud, nruab nrab thiab qis ntawm lub plawv.
Tag nrho cov khoom nruab nrog yog permeated los ntawm sympathetic fibers, thaum lawv innervate tsis tau tsuas yog lub myocardium, tab sis kuj cov khoom ntawm lub conduction system. Parasympathetic preanglionic neurons koom nrog hauv plawv innervation ntawm lub cev yog nyob rau hauv medulla oblongata. Cov axons cuam tshuam nrog lawv txav ntawm cov hlab ntsha vagus. Tom qab cov hlab ntsha vagus nkag mus rau hauv lub hauv siab kab noj hniav, ceg uas muaj nyob rau hauv cov hlab ntsha ntawm lub plawv tawm ntawm nws.
Derivatives ntawm lub paj hlwb vagus, uas khiav ntawm cov hlab plawv, yog parasympathetic preganglionic fibers. Excitation los ntawm lawv kis mus rau intramural neurons, thiab tom qab ntawd, ua ntej ntawm tag nrho cov, mus rau lub Cheebtsam ntawm kev coj system. Cov kev cuam tshuam uas tau kho los ntawm txoj cai vagus paj hlwb feem ntau yog hais los ntawm cov hlwb ntawm lub sinoatrial node, thiab sab laug - los ntawm lub atrioventricular node. Cov hlab ntsha vagus tsis tuaj yeem cuam tshuam ncaj qha rau ventricles ntawm lub plawv. Cov nyhuv inotropic ntawm cardiac glycosides yog raws li qhov no.
Intramural neurons
Intramural neurons tseem nyob hauv plawv hauv cov neeg coob, thiab lawv tuaj yeem nyob ob leeg thiab sib sau ua ke hauv ganglion. Cov xov tooj tseem ceeb ntawm cov hlwb no nyob ib sab ntawm cov pob txha sinoatrial thiab atrioventricular, sib sau ua ke nrog efferent fibers nyob rau hauv lub interatrial septum, intracardiac plexus ntawm paj hlwb. Nws muaj tag nrho cov ntsiab lus uas xav tau txhawm rau kaw lub zos reflex arcs. Nws yog rau qhov noVim li no, lub paj hlwb intramural hlab ntsha apparatus raug xa mus rau qee kis mus rau metasympathetic system. Dab tsi ntxiv nthuav txog cov nyhuv inotropic?
Txoj kev cuam tshuam ntawm paj hlwb
Thaum cov hlab ntsha tsis muaj zog innervate cov ntaub so ntswg ntawm cov pacemakers, lawv tuaj yeem cuam tshuam rau lawv qhov excitability thiab yog li ua rau muaj kev hloov pauv hauv qhov zaus ntawm kev tsim cov peev txheej thiab lub plawv contractions (chronotropic effect). Tsis tas li ntawd, kev cuam tshuam ntawm cov hlab ntsha tuaj yeem hloov pauv tus nqi ntawm electrotonic kis ntawm excitation, thiab yog li lub sijhawm ntawm cov theem ntawm lub plawv voj voog (dromotropic teebmeem).
Txij li thaum qhov kev txiav txim ntawm cov neeg kho kom haum xeeb nyob rau hauv qhov muaj pes tsawg leeg ntawm lub paj hlwb muaj kev hloov pauv hauv lub zog metabolism thiab qib ntawm cyclic nucleotides, feem ntau, cov hlab ntsha tsis muaj zog tuaj yeem cuam tshuam lub zog ntawm lub plawv contractions, uas yog, cov nyhuv inotropic.. Raws li kev cuam tshuam ntawm neurotransmitters hauv kev kuaj mob, cov txiaj ntsig ntawm kev hloov pauv tus nqi ntawm qhov pib excitation ntawm cardiomyocytes, uas raug xaiv los ua da dej motropic, tau ua tiav.
Txhua txoj hauv kev no los ntawm cov hlab ntsha cuam tshuam rau myocardial contractility thiab lub plawv dhia yog qhov tseem ceeb tshaj plaws, tab sis yog qhov thib ob rau cov txheej txheem myogenic uas hloov pauv cov kev cuam tshuam. Qhov tsis zoo inotropic nyhuv nyob qhov twg?
Cov paj hlwb vagus thiab nws cov teebmeem
Raws li qhov tshwm sim ntawm kev ua rau lub paj hlwb vagus, ib qho chronotropic tsis zoo tshwm sim, thiab tawm tsam nws keeb kwm yav dhau - cov nyhuv inotropic tsis zoo (cov tshuaj yuav tau tham hauv qab no) thiabdromotropic. Muaj cov teebmeem tonic tas li ntawm bulbar nuclei ntawm lub plawv: yog tias nws raug txiav ob sab, lub plawv dhia nce los ntawm ib thiab ib nrab mus rau ob thiab ib nrab zaug. Yog tias qhov khaus khaus muaj zog thiab ntev, ces qhov cuam tshuam ntawm cov hlab ntsha vagus tsis muaj zog nyob rau lub sijhawm lossis txawm tias nres. Qhov no yog hu ua "kev khiav tawm" ntawm lub siab los ntawm kev cuam tshuam.
Kev sib cais ntawm tus neeg nruab nrab
Thaum cov hlab ntsha vagus tau txhawb nqa, cov txiaj ntsig tsis zoo chronotropic cuam tshuam nrog inhibition (lossis qeeb) ntawm impulse tiam hauv lub pacemaker ntawm lub sinus node. Thaum kawg ntawm cov hlab ntsha vagus, thaum nws khaus, tus neeg nruab nrab, acetylcholine, raug tso tawm. Nws kev cuam tshuam nrog muscarinic-sensitive cardiac receptors nce permeability ntawm cov cell membrane ntawm pacemakers rau cov poov tshuaj ions. Yog li ntawd, membrane hyperpolarization tshwm sim, qeeb los yog suppressing txoj kev loj hlob ntawm qeeb spontaneous diastolic depolarization, vim hais tias ntawm cov membrane muaj peev xwm ncav cuag ib tug tseem ceeb theem tom qab, uas cuam tshuam rau lub slowing ntawm lub plawv dhia. Nrog muaj zog stimulation ntawm lub paj hlwb vagus, tsub kom diastolic depolarization tshwm sim, hyperpolarization ntawm pacemakers tshwm, thiab lub plawv nres kiag li.
Thaum lub sij hawm vagal cuam tshuam, lub amplitude thiab lub sij hawm ntawm qhov kev ua ntawm atrial cardiomyocytes txo. Thaum cov hlab ntsha vagus stimulated, atrial stimulation pib nce, automation yog suppressed thiab conduction.atrioventricular node qeeb qeeb.
Electrical fiber stimulation
Hluav taws xob stimulation ntawm cov fibers uas tshwm sim los ntawm stellate ganglion ua rau kom lub plawv dhia ceev thiab nce hauv myocardial contractions. Tsis tas li ntawd, cov nyhuv inotropic (zoo) yog txuam nrog kev nce hauv permeability ntawm cardiomyocyte membrane rau calcium ions. Yog tias cov calcium uas tam sim no tau nce, theem ntawm electromechanical txuas txuas ntxiv, ua rau muaj kev nce hauv myocardial contractility.
Inotropics
Cov tshuaj Inotropic yog cov tshuaj uas ua rau kom myocardial contractility. Cov nto moo tshaj plaws yog cardiac glycosides ("Digoxin"). Tsis tas li ntawd, muaj cov tshuaj uas tsis yog-glycoside inotropic. Lawv tsuas yog siv nyob rau hauv mob plawv tsis ua hauj lwm los yog thaum muaj mob hnyav decompensation nyob rau hauv cov neeg mob uas mob plawv tsis ua hauj lwm. Cov tshuaj tsis-glycoside inotropic tseem ceeb yog: Dobutamine, Dopamine, Norepinephrine, Adrenaline. Yog li, cov nyhuv inotropic hauv kev ua haujlwm ntawm lub plawv yog qhov hloov pauv ntawm lub zog uas nws cog lus.
