Sinoatrial (SA) node fibers muaj peev xwm depolarize spontaneously kom txog rau thaum lub peev xwm ntawm txog −40 mV, uas ua rau muaj peev xwm ua haujlwm tshiab (Fig. 2.3). Cov pacemaker muaj peev xwm kis tau mus rau kev ua haujlwm myocardial fibers, ua rau muaj peev xwm ua haujlwm myocardium (Fig. 2.3).
Thaum qhov pib mus txog ntawm SA node dab tsi channel qhib ua rau ntxiv depolarization ntawm daim nyias nyias?
Thaum qhov pib mus txog ntawm SA node (ib qho autorhythmic cell), dab tsi channel qhib ua rau ntxiv depolarization ntawm daim nyias nyias? Ceev calcium channels Yog, tsis zoo li cov paj hlwb lossis cov leeg mob plawv, cov calcium uas ceev ceev yog lub luag haujlwm rau lub sijhawm depolarization ntawm autorhythmic cell ua lub peev xwm.
Yuav ua li cas thaum SA node ncav cuag qhov pib?
Thaum lub peev xwm pacemaker hauv SA node nce mus txog qhov pib, ib qho peev xwm tsim tawm.
SA node mus txog qhov pib li cas?
Cells tuaj yeem ncav cuag qhov pib muaj peev xwm los ntawm kev txhawb nqa los ntawm cov hlwb uas nyob ib sab, lossis, yog tias lawv yog cov hlwb pacemaker, muaj qhov tsis siv neeg. Tus cwj pwm, lub peev xwm ua pacemaker muaj peev xwm tsuas muaj peb theem, xaiv theem xoom, peb, thiab plaub. Theem xoom yog theem ntawm depolarization.
Yuav ua li cas thaum qhov pib mus txog?
Thaum lub depolarization ncav cuag -55 mV tus neuron yuav tua qhov muaj peev xwm ua. Qhov no yog qhov pib. Yog tias cov neuron tsis ncav cuag qhov tseem ceeb ntawm qhov pib, ces tsis muaj peev xwm ua rau hluav taws. … Nco ntsoov, sodium muaj tus nqi zoo, yog li cov neuron tau zoo dua thiab ua rau depolarized.
