It is the microscopic study of tissues of the body and how these tissues are organized to form organs. The word "histology" is derived from two Greek words, histo="tissue" and logos="study".
In histology, two main components of the tissues are studied:
(i) cells and
(ii) extracellular matrix.
Importance of Histology:
As gross anatomy shows you the picture of the body from outside, histology goes deep into the body to show you the microscopic features.
In this way, students can correlate how microscopic structures are related with the gross structures.
Knowledge of histology also aids in understanding the pathology of tissues. This is because histology gives you the normal image of a tissue while pathology discusses what changes occur in this normal tissue when it becomes abnormal or diseased. So, there is always a link between histology and pathology.