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Jaina Biology
and seven and half days and nights of the embryonic development.43 This total gestation period or time of development, for human beings is almost equal to "the total gestation period of about 280 days for human beings, from the beginning of the last menstrual period before conception until the time of birth", as explained by modern Biology.44
Formation of the Heart (Hiyaya )44/a
Jaipa Biology does not throw much light on the formation of the heart. But its reference to the generation of sonita (blood) in the sixth month of the growth of the foetus 45 and the development of circulatory vessels (700 Širās and 9 dbamanis in the seventh month)46 and to heart (hiyayam) in the adult suggests that in contrast to many47 organs which develop in the embryo without having to function at the same time, the heart and the circulatory system function, while undergoing development.
According to Modern Biology, 48 "The heart forms first as a sample tube from the fusion of two thin-walled tubes beneath the developing head”. In this early condition it is essentially like a fish heart, consisting of four chambers arranged in a series : the sinus venosus, which receives blood from the veins, the single atrium, the single ventricle, and the arterial cone, which leads to the aortic arches.49
“In the beginning the heart is a fairly straight tube, with the atrium lying posterior to the ventricle ; but since the tube grows faster than the points to which its front and rear ends are attached it is forced to bulge out to one side. The ventricle then twists in an S-shaped curve down and in fornt of the atrium, coming to lie posterior and ventral to it as it does in the adult. The sinus venosus gradually becomes incorporated into the atrium as the latter grows around it, and most of the arterial cone is merged with the wall of the ventricle" 50
43. Tandula Veyaliya, 2, p. 6 43/a Bhagavati Sūtra, 1.7.62. 44. Bhagavati Sūtra, 1.7.62, 45. Biology, p. 440. 45/a Tandula Veyaliya 16, p. 35 46. Taņdula Veyaliya 2 p. 6. 47. Ibid. 48. Ibid. 16, p. 35. 49. Biology, D. 440 50. Biology pp. 440-1.
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