embryonic period

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Related to embryonic period: fetal period

embryonic period

the earliest period or phase of lung development in utero, lasting from the third week after conception to the sixth week. It is sometimes not named as a defined period of lung development, which is instead considered to begin with the following pseudoglandular period. During this period, a ventral respiratory diverticulum (lung bud) arises from the caudal end of the laryngotracheal groove and grows into bronchial buds and the primordial trachea. Also called embryonic phase.

embryonic period (em″breon´ik pe´reod),

n the stage between the second and eighth week of embryonic development, during which differentiation of organs and organ systems occurs.


emanating from or pertaining to embryo. See also embryo.

embryonic death
see early embryonic mortality (below).
embryonic disk
larger cells of the mammalian blastocyst which develop into the embryo.
early embryonic mortality
death of the embryo, i.e. before it becomes a fetus; a principal cause of temporary infertility in farm livestock. Amongst causes are errors in timing of insemination, chromosomal defects, asynchronous development of the endometrium.
embryonic period
see embryo.
embryonic regulation
ability of embryonic tissues to recognize changes in their size and location and to make the necessary adjustments to form the disk-shaped assembly of appropriate structures.
embryonic stem cell
stem cell of fetal origin.
embryonic vesicle
see chorionic vesicle.
References in periodicals archive ?
At these temperatures, this range in embryonic period falls within that typical of dorid nudibranchs with similarly sized eggs and planktotrophic development and is also at least a week shorter than embryonic periods known for species with non-feeding modes of development in the NE Pacific Ocean (Hadfield and Switzer-Dunlap 1987; Goddard 1996; Goddard and Hermosillo 2008).
However, it is estimated that most losses of pregnancy occur in the first 50 d of gestation, during the embryonic period.
By stage 10 of the embryonic period (circa 22 days), the embryo is 2.
The timing and sequence of events in the development of the human respiratory system during the embryonic period proper.
The percentage of females that parasitized, the parasitisto rate (number of eggs parasitized/number of eggs in the cardboard), embryonic period (between egg to adult emergence), emergence rate (eggs with a hole made were counted to evaluate), number of individuals/egg, sex ratio (number of females/number of females + males) and longevity of female offspring were evaluated.
All tests developed to date cover only the embryonic period and probably predict only the potential to cause structural malformation.
1] micromeres prevents the formation of ctene rows and their associated endodermal canals during the embryonic period, supporting this cell fate assignment[3, 5].
The other 3 embryonic periods, including embryonic development, postembryonic development, and emergence stage of the 1st breathing pore, also showed the similar trends with variations in temperature.