What do we know about a science like histology? Indirectly with its main provisions could be found at school. But in more detail this science is studied in higher school (universities) in medicine.
At the level of the school curriculum, we know that there are four types of tissues, and they are one of the basic components of our body. But people who are planning to choose or have already chosen medical profession as their profession, need to become more familiar with such a branch of biology as histology.
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 section of science includes several others.
As an academic discipline, this science includes:
- cytology (the science that studies the cell);
- embryology (studying the process of embryo development, the features of the formation of organs and tissues);
- general histology (the science of the development, functions and structure of tissues, studies the features of tissues);
- private histology (studies the microstructure of organs and their systems).
The levels of organization of the human body as a holistic system
This hierarchy of the object of study of histology consists of several levels, each of which includes the next. Thus, visually imagine this as a multi-level nested doll.
- Organism . This is a biologically integral system that is formed in the process of ontogenesis.
- Organs This is a complex of tissues that interact with each other, performing their basic functions and ensuring that the organs perform basic functions.
- Tissues . At this level, cells are combined with derivatives. Tissue types are being studied. Despite the fact that they can consist of a variety of genetic data, their basic properties determine the base cells.
- Cells . This level represents the basic structural and functional unit of tissue - the cell, as well as its derivatives.
- Subcellular level . At this level, constituent cells are studied - the nucleus, organelles, plasmolemma, cytosol and more.
- Molecular level . This level is characterized by the study of the molecular composition of cell components, as well as their functioning.
Fabric Science: Tasks
As for any science, a number of tasks are also identified for histology that are performed during the study and development of 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 cell features such as adaptability, variability, and reactivity;
- development of the theory of tissue regeneration after damage, as well as methods of tissue replacement therapy;
- interpretation of the molecular genetic regulation device, the creation of new methods of gene therapy, as well as the movement of stem embryonic cells;
- studying the process of human development in the embryo phase, other periods of human development, as well as problems with reproduction and infertility.
Stages of development of histology as a science
As you know, the field of study of the structure of tissues was called "histology". What is it, scientists began to find out before our era.
So, in the history of the development of this sphere, three main stages can be distinguished - domicroscopic (until the 17th century), microscopic (until the 20th century) and modern (until today). We consider each of the stages more specifically.
Domicroscopic period
At this stage, such scientists as Aristotle, Vesalius, Galen and many others were involved in histology in its initial form. At that time, the objects of study were tissues that were separated from the human or animal organism by the preparation method. This stage began in the 5th century BC and lasted until 1665.
Microscopic period
The next, microscopic, period began in 1665. Its dating is due to 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 publication "Monograph", where the concept of "cell" was first used.
Prominent scientists of this period who studied tissues and organs were Marcello Malpigi, Anthony van Levenguk and Nehemiah Grue.
The cell structure was continued to be studied by such scientists as Jan Evangelista Purkinje, Robert Brown, Matthias Schleiden and Theodore Schwann (his photo is posted below). The latter eventually formed a cellular theory, which is relevant to this day.
A science such as histology continues to develop. What is it, at this stage, are studying Rudolf Virchow, Camillo Golgi, Theodore Boveri, Keith Roberts Porter, Christian Rene de Duve. Also related to this are the work of other scientists, such as Ivan Dorofeevich Chistyakov and Peter Ivanovich Peremezhko.
The modern stage of development of histology
The last stage, a science that studies the tissues of organisms, begins in 1950. The time frame was determined so because it was then that an 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
We proceed directly to the main object of study of such a science as histology. Tissues are evolutionary systems of cells and non-cellular structures that are combined due to the similarity of structure and having common functions. In other words, tissue is one of the components of the body, which is a union of cells and their derivatives, and is the basis for building the internal and external organs of a person.
Tissue is not exclusively made up of cells. The composition of the tissue may include the following components: muscle fibers, syncytium (one of the stages of the development of male sex cells), platelets, red blood cells, horny scales of the epidermis (post-cellular structures), as well as collagen, elastic and reticular intercellular substances.
The emergence of the concept of "fabric"
The concept of “fabric” was first applied by the English scientist Nehemiah Grew. Having studied plant tissue then, the scientist noticed the similarity of cellular structures with the fibers of textile fabric. Then (1671) fabrics were described by such a concept.
Marie Francois Xavier Bichat, a French anatomist, in his works further strengthened the concept of tissues. Varieties and processes in tissues were also studied by Aleksei Alekseevich Zavarzin (theory of parallel series), Nikolai Grigoryevich Khlopin (theory of divergent development) and many others.
But the first classification of tissues in the form in which we now know it was first proposed by German microscopists Franz Leydig and Keliker. According to this classification, tissue types include 4 main groups: epithelial (borderline), connective (musculoskeletal), muscle (contracted) and nervous (excitable).
Histological examination in medicine
Today, histology as a science that studies tissues helps a lot in diagnosing the state of internal organs of a person and prescribing further treatment.
When a person is diagnosed with a suspected malignant tumor in the body, histological examination is one of the first to be prescribed. This is, in fact, the study of a tissue sample from the patient’s body, obtained by biopsy, puncture, curettage, using surgical intervention (excision biopsy) and other methods.
Thanks to histological examination, a science that studies the structure of tissues helps to prescribe the most appropriate treatment. In the photo above, you can see a sample of tracheal tissue stained with hematoxylin and eosin.
Such an analysis is carried out if it is necessary:
- confirm or deny the diagnosis made earlier;
- establish an accurate diagnosis in the event that controversial issues arise;
- determine the presence of a malignant tumor in the early stages;
- observe the dynamics of changes in malignant diseases in order to prevent them;
- carry out differential diagnosis of processes occurring in 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 treatment already prescribed.
Tissue samples are examined in detail under a microscope in a traditional or accelerated manner. The traditional method is longer, it is used much more often. In this case, paraffin is used.
But the accelerated method makes it possible to get the results of the analysis within an hour. This method is used when there is an urgent need to decide on the removal or preservation of the patient’s organ.
The results of histological analysis, as a rule, are the most accurate, since they make it possible to study tissue cells in detail for the presence of a disease, the degree of damage to the organ, and methods of its treatment.
Thus, a science that studies tissues makes it possible not only to study the structure of an organism, 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.