What field of study focuses on tiny structures found in living tissues?

The field of study that focuses on tiny structures found in living tissues is histology. Histology is the microscopic study of tissues, involving the examination of cells and their arrangement within different types of tissues. This discipline is essential for understanding how tissues function in normal and abnormal states, including the identification of cellular structures, organization, and their relationship to the overall function of organs.

Histologists use various staining techniques and microscopy to visualize these tiny structures at a cellular level, which is crucial for diagnosing diseases, understanding developmental biology, and conducting research in areas such as oncology and regenerative medicine. This emphasis on microscopic anatomy sets histology apart from other fields like anatomy, which addresses overall body structures, pathology, which studies disease processes, and physiology, which focuses on the functions and mechanisms in living organisms.