Respiratory tract infection, exposure to cold air, and emotional stress are all known triggers of:

Arrange these elements of the intrinsic conduction system in the order that a depolarizing impulse travels during a normal heartbeat. rank from first to last. do not overlap any tiles. view available hint(s) reset av nodeav bundleinternodal pathwaysbundle branchessa nodepurkinje fibers

Match the following terms describing electrical events with the correct phases of the cardiac cycle. the ventricular muscle cells depolarize at the start of this phase. during this phase, na+ entry through the funny channels causes the pacemaker potential of sa nodal cells to gradually become less negative until it reaches threshold. the ventricular muscle cells repolarize right before this phase. the cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. a. isovolumetric relaxation b. ventricular ejection c. isovolumetric contraction d. ventricular filling

This is the interaction of two organisms where one is and the other is neither nor harmed.