Embryo Images Normal and Abnormal Mammalian Development is a tutorial that uses scanning electron micrographs (SEMs) as the primary resource to teach mammalian embryology. The 3-D like quality of the micrographs coupled with selected line drawings and minimal text allow relatively easy understanding of the complex morphological changes that occur in utero. Because early human embryos are not readily available and because embryogenesis is very similar across mammalian species, the majority of micrographs that are utilized in this tutorial are of mouse embryos. The remainder are human.

     Navigating this site is relatively self-explanatory. This tutorial is divided into units that may be studied in any order. However, it is recommended that the unit entitled "Body Form" be examined first. Each page has a navigation bar on the left of the screen that allows movement forward and backward within a unit. In addition, each image may be accessed by selecting its number under 'Select Image.' Because some images are part of a grouping (eg, 10, 10a, 10b) the key number should be selected followed by the use of forward . The table of contents for each unit may be accessed by clicking on . indicates the homepage which allows access to any of the units. All of the images have a legend that indicates the age of the embryo. If it is a mouse embryo, the approximate equivalent human age is indicated. To minimize labeling, color-coding is widely used . To view the micrographs without color, the cursor may be placed on the image.

     Two units currently under development are designed to provide information regarding pre-implantation and fetal development as well as the genesis of birth defects.

     This tutorial was developed by Drs. Kathleen K. Sulik and Peter R. Bream Jr. with the assistance of Mr. Tim Poe and Ms. Kiran Bindra. Financial support has been provided by the Greenwood Genetic Center, Greenwood, SC and the University of North Carolina at Chapel Hill. The SEMs used in this tutorial are from the K.K. Sulik collection. The line drawings have been used with permission from Lippincott Williams & Wilkins and are from the 6th and 7th editions of Langman's Medical Embryology by T.W. Sadler. These drawings may not be reproduced without the permission of the publisher. Please email your questions and comments to the Educational Technology Group.