When the egg is laid, some embryonic development has occurred and usually stops until proper cell environmental conditions are established for incubation to resume. The complexity of the development cannot be understood without training in embryology.
A chick emerges after a brief three weeks of incubation. Nucleus of the egg is surrounded by the negligible amount of yolk.One of the greatest miracles of nature is the transformation of the egg into the chick. The central flask shaped area that is enclosed of white yolk is called. Direito civil brasileiro carlos roberto goncalves vol 1 azw3 Two end of the egg are some fibrous,rope like twisted structure. The layer of yellow yolk is thicker than those of the white yolks. Two types of membrane, shell membrane and vitelline membrane. If we had a way to label cells from rows on either side of the axis of extension, they would be found to mix with one another as a result of these oriented intercalation events. If you continue browsing the site, you agree to the use of cookies on this website.Ĭells converge by intercalating perpendicular to the axis of extension, resulting in the overall extension of the tissue in a preferred direction. The auditory vesicles develop at the level of the myencephalon. The depression at the ventral side of the diencephalon develops in to the hypophysis ( hypo under not visible in this fig.). The dorsal projection of the dieencephalon is also visible and will differentiate in to the epiphysis (epi at the upper side). The eye vesicles differentiate as two lateral projections of the diencephalon and come in contact with the external layer (ectoderm) to form the optic cup (neurectoderm) and the lens (ectoderm). The fore and hind limbs at the level of the 16 th to the 20 th respectively the 27 th to the 32 th somite pairs are visible as small buds at an incubation time of about 3 days. Due to the cranial flexure, the pharyngeal region ( region of the trachea) is now located at the ventral side of the head.
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