Fig. 5

The relationship between the morphological changes in the heart primordium and the beginning of the calcium transient and contraction. The drawings at the left of each panel show the morphological changes in the heart primordium. The drawing in A represents the heart primordium before initiation of the calcium transient and contraction. In B, the green and yellow areas correspond to the expression of calcium transients and contraction, respectively. The drawing in C represents the heart primordium after the calcium transient and contraction have already begun. These changes shown in A, B, and C were observed at approximately E 10.0 days. The drawings in D and E represent the heart primordium at E 10.25 days and E 10.5 days, respectively. The images in the center of each panel represent the whole embryos corresponding to each cartoon. The images at the right of each panel were recorded after removal of the pericardium of each embryo shown in the center