Orange cut in cross-section.
Orange cut in a longitudinal section.
Histology is literally, "the study of tissue." Tissue sections cannot be produced which are completely accurate and representative "snap shots" of the tissue in its' living state. But instead, histologists seek to preserve the tissue in the most life-like state possible. In reality, what we are able to achieve is a somewhat distorted, yet permanent, representation of the tissue's living condition.
Histologists must learn to be able to visualize how specimen handling, including gross dissection and tissue processing, affect the appearance of tissues at both the macroscopic and microscopic levels.
A clear understanding of anatomy and the ability to spatially visualize the specimen in three dimensions is extremely helpful. The histologist must use this background knowledge and understanding to visual identify any alterations in the tissue appearance caused during gross dissection and/or tissue processing; Apply this insight for correct specimen orientation during embedding.
In visually assessing and identifying tissue samples, note that:
- Some sections cut through tubes or invaginations are not large enough to show the entire lumen.
- Many cells and tissues are organized into partitions, which divide the structure into numerous smaller areas which may be transected in any given specimen.
- Many submitted specimens may not show all the structural details that are depicted in images in histology atlases or anatomy textbooks.
- You may become quite skillful at visually identifying many specimen types, but you MUST still verify the specimen type using an electronic or paper-based worksheet.