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 ?
Most of the studies are about the embryonic period and the best studies about hatching and after hatching are mostly done on gallus domesticus [18].
For the chromodorid Felimare californiensis (= Hypselodoris californiensis) (Bergh, 1879) we inferred mode of development based on estimates of embryonic period and egg size.