Contents • • • • • • • • Introduction Historically, an important way of teaching embryology is by direct observation of histological sections at different stages of development. Even today the best way to observe anatomical development and relationships is by direct observation in serial sections through the embryo and fetus. The sections below are from the original teaching set prepared at UNSW that were digitized and put online in 1996 as a teaching resource. The Stage 13 and 22 images are available in at least two formats, an unlabeled set (image 1 - 49) and a labeled set (image 50 - 98) in a rostro-caudal sequence (head to tail).

Jan 05, 2012  Chicken: 72 h: This page on the embryology in chicken relates to the following. The rotation of the embryo to the left is arrived such behind the region of the heart and only the caudal part of the embryo must twist 90 degrees. The two flexures in the head region are almost completed. Left wholemount preparation and right cross section. Book - The Early Embryology of the Chick - Figures. Dissection of a 35-hour chick embryo. Of 33-hour chick. The location of each section is indicated on a.

Stage 22 embryo also has a set of selected images showing more detail of some organ and tissue development. In addition, there are now 3D animations based upon reconstruction of the embryos from these serial sections. 2011 - Selected slides are currently being rescanned at to show specific developmental details. Author Comments Start here by looking through the early (week 4) embryo (stage 13) labeled images.

It is not so important to identify every single feature, observe what structures are present and where they are in the middle of the embryonic period (week 4). Then if you like, look through the unlabeled images. What can you now recognise? Next look through the late (week 8) embryo (stage 22) labeled images as you did before. Then look through the same embryo stage selected labeled images.

These show organ and tissue development of specific structures by the end of the embryonic period. What has changed? Finally put the systems together by watching the embryo animations based upon these sections. How different are the embryonic systems to the adult anatomy? More about these. Links: Carnegie Stage 13 About Stage 13 Embryo Sections - This image is from a serial section of a 6mm CRL pig embryo with some features of the Stage 14 embryo. This embryo is approximately equal to the day 42 human embryo.

Use these serial images to identify internal features and relationships that exist within the embryo at this stage. Then compare these images with the later features of the Carnegie stage 22 human embryo.

The mechanisms of development of posterior levels of neural tubes of chick embryos were analyzed by study of serial cross‐sections of a continuous series of normal embryos between 40 to 72 hours of incubation. Two extirpation experiments were performed in ovo on other embryos of the same stages. Descriptive studies revealed the presence of an overlap zone in which two types of neural tube formation occurred. Open neural tube formation (by fusion of neural folds) occurred dorsally in this region; closed neural tube formation (by canalization of solid medullary cord tissue) occurred ventrally. Queen fighters mugen full game download.

Extirpation of the posterior end of the neural plate produced defects within the lumbosacral region, indicating that the posterior neural plate participates in the formation of the lumbosacrum, and that the overlap zone is therefore in the lumbosacral region. Extirpation of the prospective neural tissue in the anterior end of the tail bud indicated that only the most posterior levels of the neural tube originate exclusively by cavitation of the tail bud. In both extirpation experiments a neural tube formed independently within the tail bud tissue, indicating that formation of the neural tube in this region is not dependent upon direct continuity with neural tissue anteriorly.