Protein signalling in heart development Protein signalling in heart development The heart is the first functional organ in a vertebrate embryo. There are 5 stages to heart development. Specification of cardiac precursor cells: The lateral plate mesoderm delaminates to form two layers: the dorsal somatic (parietal) mesoderm and the ventral splanchnic (visceral) mesoderm. The heart precursor cells come from the two regions of the splanchnic mesoderm called the cardiogenic mesoderm. These cells can differentiate into endocardium which lines the heart chamber and valves and the myocardium which forms the musculature of the ventricles and the atria. The heart cells are specified in anterior mesoderm by
How Many More Times Wolf's "How Many More Years" (1951), as well as other songs by blues musicians he admired at the time of recording. In 1970, "How Many More Times" was dropped from Led Zeppelin's typical setlist, although they continued to perform it on occasion until the early stages of their 1975 North American tour, when it was re-introduced in full as a result of Jimmy Page's injured finger, which temporarily prevented him from playing the more challenging "Dazed and Confused". In a contemporary review for "Led Zeppelin" on release, John Mendelsohn of "Rolling Stone" called "How Many More Times" as the album's