ABSTRACT
The cause of some phenotypes may be self-evident in the pattern of structural lesions observed at necropsy or, more commonly, after a combination of additional histopathologic assessment, functional analysis, and/or biochemical or molecular testing. In some instances, however, more subtle changes in organelle anatomy warrant further morphologic evaluation at the subcellular level. Such ancillary studies involve ultrastructural (electron microscopic [EM]) evaluation. The information provided by examining organs and tissues using EM promotes a deeper understanding of biological events by revealing the cytoarchitectural basis for normal cell and tissue function as well as more exact explanations about causes and consequences of disease.
