[lemma=heart] [lemma=and] [lemma=muscle] [tag=NNS] [□]
[lemma=heart] [lemma=and] [lemma=muscle] [tag=NNS] [□=□]
[lemma=heart] [lemma=and] [lemma=muscle] [tag=NNS] [□ | □]
Ions flowing into or out of cells underlie such vital functions as electrical signaling in neurons and in heart and muscle cells , secretion of hormones and neurotransmitters , cell volume regulation , kidney function and fertilization .