What is Histology?
Histology is the branch of science that studies biological tissues, whether of animals or plants. This branch looks at the formation, structure and function of living tissues.
Tissues are formed from the junction of several cells. Therefore, the analysis made for this study is on a microscopic scale, being necessary for this the use of equipment that allow the observation of the cells. Incidentally, histology was only able to develop after the invention of the optical microscope.
As a discipline, histology is part of the Biological and Health Sciences. In biology, however, it is usually subdivided according to the focus given to the object of study. For example, Animal Histology studies the tissues of animals; the histology Plant, the study of plant tissues; and Human Histology, is intended for the study of the tissues of the human body.
Etymologically, the word histology originated from the junction of the Greek term hystos, which means “tissue”, and logos, which means “study”.
In the human organism, according to the division made by histology, the tissues are organized into four basic groups: epithelial tissue, connective tissue, muscle tissue and nervous tissue.
Each of these tissues presents particular organization and functions:
- Epithelial tissue:very close cells, mainly serving to coat and protect internal and external surfaces of the body. It protects the body against the penetration of microorganisms and other physical aggression.
- Connective tissue:cells with spaces between them, serving to guarantee the sustentation and connection between the other tissues and organs of the body. It serves to unite and separate the organs.
- Muscle tissue:cells have elongated appearance. It serves so that the body can move. The plain, striated and skeletal tissue are some examples.
- Nervous tissue:formed by neurons and neuróglias (protective and supporting cells). Responsible for managing all the vital functions of the organism.
On the other hand, plant tissues are divided into two main groups: meristematic tissues and adult tissues.
The meristems are characterized by great capacity of cell division (mitosis) and are formed by undifferentiated cells.
From the development of meristematic tissues, adult tissues (the permanent tissues of the plant) are formed, which have specific functions and are divided into: lining fabrics, filling tissues (parenchyma), supporting tissues and conducting tissues.