96 Hour Chick Embryo Serial Section

24 hr chick Note that in the 24 hour chick, Hensen's node is located further caudally and the primitive streak is present only at the posterior end of the embryo. As Hensen's node retreats posteriorly, the organs which define the embryonic axis are formed anterior to it. CHICK EMBRYO AT 24 HOURS At 24 hrs. Incubation period the chick embryo is oval in shape. The primitive streak is seen. 48 HOUR CHICK EMBRYO 96 HOUR CHICK EMBRYO.

At about 33 hours after fertilization, the embryo is about 4 mm long and the first flexion of the originally straight embryo starts in the head region. The cranial flexure will be visible a few hours later. At this stage 12 to 13 somites are formed. The eye vesicles are rather large. The forebrain vesicle or prosencephalon will divide, the midbrain vesicle or mesencephalon remains undivided while the hindbrain vesicle or rhombencephalon will form a series of smaller neuromeres. The sinus rhomboidalis (diamond-shaped) is still present as the only opening of the neural tube and the primitive streak is only rudimentary. Symbolmt font mac osx.

The infundibulum (= derived from the diencephalon) appears as a half circular structure at the ventral side of the caudal part of the forebrain. The notochord or chorda dorsalis ends just behind this ventral vesicle. Later on, 36 hours after fertilization, the heart, which has a bilateral origin in the mesodermal layer, is a S-shaped tube which protrudes to the right of the embryo (in upper view). Outside, in the area vasculosa (= forseen of blood vessels) the formation of blood islands continues.

The primitive streak can only still be discerned below the sinus rhomboidalis. Early embryonic developmental features that are shown on this page: • Whole mount preparation 33 hours () • Whole mount preparation 36 hours () • Cross sections 36 hrs; formation of eye, heart and intestines ( ) Stage 33 hours Information: At about 33 hours after fertilization, the embryo is about 4 mm long and the first flexion of the originally straight embryo starts in the head region and the cranial flexure will be visible a few hours later. At this stage 12 to 13 somites are formed. The eye vesicles are rather large. The forebrain vesicle or prosencephalon will divide, the midbrain vesicle or mesencephalon remains undivided while the hindbrain vesicle or rhombencephalon will form a series of smaller neuromeres. The sinus rhomboidalis (diamond-shaped???) is still present as the only opening of the neural tube and the primitive streak is only rudimentary.