title: Ontogenetic changes in pacemaker activity in chick heart.
mesh_terms: D000375:Aging; D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D004558:Electric Stimulation; D006321:Heart / Q000254:growth & development / Q000502:physiology*; D006325:Heart Atria; D008839:Microelectrodes; D010138:Pacemaker, Artificial; D011199:Potentiometry; D013997:Time Factors