INITIATION AND EARLY CHANGES IN THE CHARACTER OF THE HEART BEAT IN VERTEBRATE EMBRYOS

Abstract

After a brief historical review of work on the subject prior to 1900, Patten takes up, as an anatomical foundation for what follows, the sequential formation of the primary regions of the heart; then considers the first contractions in the myocardium, shifts in the location of the pace-making center, early changes in the character of the embryonic heart beat, and electrical recordings from early tubular stages of the embryonic heart. Omitted from this review are the effect of age differences and temp. changes on heart rate, the influence of various chemical substances on the character of cardiac pulsation, and the effects of hormones.