Sequential cross sections of a 48-hour chick embryo mounted in rows on microscope slides. A prominent heart and a few branchial grooves are present. This stage is characterized by ventral flexion and dextral torsion, resulting in a C-shaped embryo.

48 Hour Chick Embryo Serial Cross Section Chart
72 Hour Chick Embryo
48 Hour Chick Embryo Cross Section
48 Hour Chick Embryo Serial Cross Sectional
96 Hour Chick Embryo
72 Hour Chick Embryo Labeled

Observation of living and plastic-embedded chick embryos

The development of chick embryos has been studied since Aristotle. It is one of the most intensely studied organisms. One reason for this is that there are great similarities between avian and mammalian embryology. Another advantage is that the embryo is relatively accessible and can be operated on or treated with teratogens (substances that perturb development) while still in ovo(in the egg). Finally, fertilized chicken eggs are available year round and can be 'held' at 10-14ºC for several weeks before being set, producing embryos upon demand.

Embedded embryos

Through the trunk region of 48 hours chick embryo with lateral body fold Neural tube. Cross Section of the 72 Hour Chick Embryo through the head and heart.
24 Hour Chick Embryo - Free download as Powerpoint Presentation (.ppt) or view presentation slides online. 24hr Chick Cross Sections. Embryology Reviewer. 48-Hour Chick Reviewer. 48hr Whole Mount Labled.
8 - Embryo of chicken (24 hour) w.m. 9 - Embryo of chicken (24 hour) serial transverse sections. 10 - Embryo of chicken (48 hour) w.m. 11 - Embryo of chicken (48 hour) serial transverse sections. 12 - Embryo of chicken (72 hour) w.m. 13 - Embryo of chicken (72 hour) serial transverse sections. 14 - Embryo of chicken (96 hour) w.m.

1. Examine plastic embedded specimens of '13-hour' or '16-hour', '24-hour', '33-hour','48-hour' and '72-hour' chick embryos. These terms refer to classic studies of chick development. In reality, chick embryos will develop at different rates for a number of reasons, including incubation temperature. In modern times, chicks always take longer to reach these stages. Two more accurate ways of describing the relative developmental age of a chick embryo are (1) the number of somites and (2) comparison to a staging series, such as the one devised by Hamburger and Hamilton (H&H; hamburger.pdf). The somites are the blocks of tissue on either side of the neural tube. Try to determine the number of somites and the H&H stage number of your embryos.

2. Try to identify the structures indicated in the diagrams. Pay particular attention to the developing circulatory system. Try to determine which germ layer forms each structure. Highlights include:

13- to 16-hour.Identify the area opaca and area pellucida. Locate the primitive streak. Hensen's node is located at the anterior end of the streak.

24-hour.Locate the neural folds and Hensen's node. Identify the anterior end of the embryo.

33-hour.The embryo is lying along the center of the blastodisc, dorsal side up. The heart is to the right, along the side of the hindbrain. It is a simple, looped tube;connected to the vitelline vein and the ventral aorta. What is the function of the vitelline vein? Identify the forebrain, midbrain and hindbrain. The optic vesicles are outpockets on either side of the forebrain. The neural plate runs along the dorsal midline and is not yet closed. You may also be able to see the notochord running along the midline.

48-hour.The head has bent forward and the body has begun to twist. The optic cup(eye) and the otic vesicle (ear) have formed. The neural tube has closed, except in the region of the hindbrain. A series of aortic arches run between the pouches

In this article we will discuss about the development stage of chick embryo, fertilized eggs are procured from recognised poultry farm and incubated in the laboratory.

1. Chick: M. 4 Hours of Incubation:

1. Four hours after incubation of the egg shows differentiation of the blastodisc into area pellucida and area opaca. (Fig. 7).

2. One quadrant of area pelluciada becomes thickened, which marks the future caudal end of embryo.

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3. After 7 to 8 hours, the thickening becomes more elongated and represented start of primitive streak.

2. Chick: W.M. 16 Hours Embryo:

Comments:

1. 16 hours after incubation the primitive streak becomes so distinct that embryos are characterized as being in primitive streak stage. (Fig. 8).

2. In fixed and stained slide, w.m. is composed of central furrow, called as primitive groove lined by thickened primitive ridges.

3. At the cephalic end of the primitive streak, closely-packed cells form thickened area, called as Hensen’s node. Part of area pellucida adjacent to the primitive streak shows increased thickness and forms embryonic elliptical shape.

4. Area pellucida assumes elliptical shape.

5. Elongated primitive streak represents long axis of future embryonic body.

6. Caudal end of the streak is that which lies close to the area opaca.

3. W.M. 18 Hours Chick Embryo:

1. It is a W.M. of 18 hours stage of chick embryo.

2. At this stage the dark peripheral area opaca and central translucent area pellucida are distinctly visible.

3. In the anterior part is present the pro-amnion, which is a small and comparatively more translucent region of area pellucida and is characterised by the absence of mesoderm.

4. In the middle of area pellucida, in the posterior half, runs a primitive streak having a primitive groove through its centre. The primitive groove is being bound by primitive folds.

5. In the anterior half of area pellucida, in the middle, runs a neural groove bound by neural folds.

6. The primitive streak and neural groove is separated by a thickening-the Hensen’s node having a small depression in the centre-the Hensen’s pit.

7. The primitive streak gives rise to an out-growth, the notochord immediately below the primitive groove.

4. W.M. of 21 Hours Chick Embryo:

1. It is a W.M. of 21 hours chick embryo.

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2. At this stage the dark peripheral area opaca and central translucent and colourless area pellucida are distinctly visible.

3. In the anterior part are present the pro-anmnion, which is a small and comparatively more translucent region of area pellucida and is characterised by the absence of mesoderm.

4. In the middle of area pellucida, in the posterior half, runs a primitive streak having a primitive groove through its centre. The primitive groove is being bound by primitive folds.

5. In the anterior half of area pellucida, in the middle, runs a neural groove bound by neural folds.

6. The primitive streak and neural groove are separated by a thickening, the Hensen’s nod having a small depression in the centre of the Hensen’s pit.

7. The primitive streak gives rise to a small outgrowth, the notochord immediately below the primitive groove and to mesoderm on either side.

8. At this stage embryonic and extra ambryonic regions have also become distinguished in the area pellucida.

9. In the anterior most part the ectoderm has given rise to head fold, which is a pocket-like extension of neural folds.

10. With the ectoderm the underlying endoderm is also transformed into a pocket-like structure the -foregut.

48 Hour Chick Embryo Serial Cross Section Chart

11. The proambion is comparatively reduced in size.