Chapter 1. Subject and Aims of Histology. Levels of Structural and Functional Organization of Living Beings
Histology (derived from the Greek word histos meaning "tissue", and logos meaning "study") is a scientific study exploring patterns of development, structure and functioning of tissues, interstitial interactions during historical and individual evolution of humans and other multicellular organisms. The focus of Histology is to study tissues, which are topographically and functionally related cell systems and their derivatives with common phylogenetic background that form organs.
Histology as a scientific and educational subject includes several sections.
Cytology is the study of the cell as a key histological element within tissues. Here, we will discuss the general and specific principles of cell structure, cytophysiology, reproduction and death mechanisms, reactive changes and regenerating capacity in case of cell damage. Embryology is the study of embryogenesis, patterns of developing germ layers, tissues and organs, critical periods of human development; embryology is closely linked to teratology (the study of congenital disorders) General histology is the study of tissue development, structure, functions, and regeneration. Specific histology deals with the microscopic structure of organs and organ systems, interstitial interactions during organogenesis, reactive and regenerative properties of organs, age-related changes during ontogenesis.
The human and animal organisms are holistic biological systems in which it is conditionally possible to distinguish several interrelated, interacting and subordinate levels of organization: molecular, subcellular, cellular, tissue and organ. Each of these levels is to a certain extent autonomous and includes structural units of subordinate levels.