What do we know about the science of histology? Indirectly, its main provisions could be found at school. But in more detail this science is studied in higher school (universities) in medicine.
We know at school level that there are four types of tissues, and they are one of the basic components of our body. But people who plan to choose or have already chosen medicine as their profession need to get acquainted with such a section of biology as histology in more detail.
What is histology
Histology is a science that studies the tissues of living organisms (humans, animals and other multicellular organisms), their formation, structure, functions and interaction. This branch of science includes several others.
As an academic discipline this science includes:
- cytology (science that studies the cell);
- embryology (the study of the process of development of the embryo, the features of the formation of organs and tissues);
- general histology (the science of the development, function and structure of tissues, studies the characteristics of tissues);
- private histology (studies the microstructure of organs and their systems).
Levels of human organizationorganism as an integral system
This hierarchy of the object of histology study consists of several levels, each of which includes the next one. Thus, it can be visually represented as a multi-level nesting doll.
- Organism. This is a biologically integral system that is formed in the process of ontogeny.
- Organs. This is a complex of tissues that interact with each other, performing their main functions and ensuring that the organs perform basic functions.
- Fabrics. At this level, cells are combined together with derivatives. The types of tissues are being studied. Although they may be composed of a variety of genetic data, their basic properties are determined by basic cells.
- Cells. This level represents the main structural and functional unit of tissue - the cell, as well as its derivatives.
- Subcellular level. At this level, the components of the cell are studied - the nucleus, organelles, plasmolemma, cytosol, and so on.
- Molecular level. This level is characterized by the study of the molecular composition of cell components, as well as their functioning.
Tissue Science: Challenges
As for any science, a number of tasks are also allocated for histology, which are performed in the course of studying and developing this field of activity. Among these tasks, the most important are:
- histogenesis study;
- interpretation of the general histological theory;
- study of the mechanisms of tissue regulation and homeostasis;
- the study of such features of the cell as adaptability, variability andreactivity;
- development of the theory of tissue regeneration after damage, as well as methods of tissue replacement therapy;
- interpretation of the device of molecular genetic regulation, the creation of new methods of gene therapy, as well as the movement of embryonic stem cells;
- study of the process of human development in the embryonic phase, other periods of human development, as well as problems with reproduction and infertility.
Stages in the development of histology as a science
As you know, the field of study of the structure of tissues is called "histology". What is it, scientists began to find out even before our era.
Thus, in the history of the development of this sphere, three main stages can be distinguished - pre-microscopic (until the 17th century), microscopic (until the 20th century) and modern (until today). Let's consider each of the stages in more detail.
Pre-microscopic period
At this stage, histology in its initial form was studied by such scientists as Aristotle, Vesalius, Galen and many others. At that time, the object of study were tissues that were separated from the human or animal body by the method of preparation. This phase began in the 5th century BC and lasted until 1665.
Microscopic period
The next microscopic period began in 1665. Its dating is explained by the great invention of the microscope by Robert Hooke in England. The scientist used a microscope to study various objects, including biological ones. The results of the study were published in the journal"Monograph", where the concept of "cell" was first used.
Prominent tissue and organ scientists of this period were Marcello Malpighi, Anthony van Leeuwenhoek and Nehemiah Grew.
The structure of the cell continued to be studied by such scientists as Jan Evangelista Purkinje, Robert Brown, Matthias Schleiden and Theodor Schwann (his photo is posted below). The latter eventually formed the cell theory, which is still relevant today.
Such a science as histology continues its development. What it is, at this stage, are studying Rudolf Virchow, Camillo Golgi, Theodore Boveri, Keith Roberts Porter, Christian Rene de Duve. Also related to this are the works of other scientists, such as Ivan Dorofeevich Chistyakov and Pyotr Ivanovich Peremezhko.
Modern stage of development of histology
The last stage of science, studying the tissues of organisms, begins in the 1950s. The time frame is defined so because it was then that the electron microscope was first used to study biological objects, and new research methods were introduced, including the use of computer technology, histochemistry and historadiography.
What are fabrics
Let's go directly to the main object of study of such a science as histology. Tissues are evolutionarily arisen systems of cells and non-cellular structures that are united due to the similarity of structure and having common functions. In other words, tissue is one of the components of the body, which isthe union of cells and their derivatives, and is the basis for building internal and external human organs.
Tissue does not consist solely of cells. The composition of the tissue may include the following components: muscle fibers, syncytium (one of the stages in the development of male germ cells), platelets, erythrocytes, horny scales of the epidermis (post-cellular structures), as well as collagen, elastic and reticular intercellular substances.
The emergence of the concept of "fabric"
For the first time the concept of "fabric" was used by the English scientist Nehemiah Grew. While studying plant tissues at that time, the scientist noticed the similarity of cellular structures with textile fibers. Then (1671) fabrics were described by such a concept.
Marie Francois Xavier Bichat, a French anatomist, in his works even more firmly fixed the concept of tissues. Varieties and processes in tissues were also studied by Aleksey Alekseevich Zavarzin (the theory of parallel series), Nikolai Grigorievich Khlopin (the theory of divergent development) and many others.
But the first classification of tissues in the form in which we know it now was first proposed by German microscopists Franz Leydig and Keliker. According to this classification, tissue types include 4 main groups: epithelial (border), connective (musculoskeletal), muscular (contractible) and nervous (excitable).
Histological examination in medicine
Today, histology, as a science that studies tissues, is very helpful in diagnosing the condition of human internal organs andprescribing further treatment.
When a person is diagnosed with a suspected malignant tumor in the body, one of the first appointments is a histological examination. This is, in fact, the study of a tissue sample from the patient's body obtained by biopsy, puncture, curettage, surgical intervention (excision biopsy) and other methods.
Thanks to histological examination, the science that studies the structure of tissues helps to prescribe the most correct treatment. In the photo above, you can see a sample of tracheal tissue stained with hematoxylin and eosin.
This analysis is carried out if necessary:
- confirm or refute an earlier diagnosis;
- to establish an accurate diagnosis in case of controversial issues;
- determine the presence of a malignant tumor in the early stages;
- monitor the dynamics of changes in malignant diseases in order to prevent them;
- to carry out differential diagnostics of the processes occurring in the organs;
- determine the presence of a cancerous tumor, as well as the stage of its growth;
- to analyze the changes occurring in the tissues with the already prescribed treatment.
Tissue samples are studied in detail under a microscope in a traditional or accelerated way. The traditional method is longer, it is used much more often. It uses paraffin.
But the accelerated method makes it possible to get the results of the analysis within an hour. This method is usedwhen there is an urgent need to make a decision regarding the removal or preservation of the patient's organ.
The results of histological analysis are usually the most accurate, since they make it possible to study tissue cells in detail for the presence of a disease, the degree of organ damage and methods of its treatment.
Thus, the science that studies tissues makes it possible not only to examine the structure of the body, organs, tissues and cells of a living organism under a microscope, but also helps to diagnose and treat dangerous diseases and pathological processes in the body.
