Figure 12.

These images obtained by 4-dimensional in vivo OCT imaging of a HH-stage 15 embryonic chick heart depict the peculiar phenomenon of end-systolic stretching of the cross section of the ventricular bend along the original dorso-ventral axis. Asterisks mark the original ventral (light blue) and dorsal (orange) midlines, which are found along the outer and inner curvatures of the ventricular bend, respectively. Note the striking increase in the thickness of the CJ layer between diastole and early end-systole (indicated by white and blue arrows). Late end-systolic stretching of the cross section of the ventricular bend leads to a slight decrease in the CJ thickness (compare blue and magenta arrows). White lines mark the diastolic length of the original dorso-ventral axis.