gENERAL PATHOMORPHOLOGY: HISTORY OF DEVELOPMENT AND RESEARCH METHODS. CELL PATHOLOGY. Degenerations. necrosis. apoptosis. general death. HEMODYNAMIC DISORDERS. INFLAMMATION. (N.Lagoda)……………………… . . (Page 70-83)
Lesson No 1
Methodical instructions for students
Theme: PATHOMORPHOLOGY: HISTORY OF DEVELOPMENT, AND RESEARCH METHODS. CELL PATHOLOGY.
Aim: to learn essence of pathomorphology, its value and place among the other medical disciplines. To learn different changes of cell injury.
Objectives of the lesson:to learn history of development of pathomorphology. To learn material and methods of research of pathoanatomy. To learn the bases of clinical and morphological analysis of cell injury.
Questions to control basic knowledge:
1. Definition of pathomorphology as a component part of pathology.
2. Main direction of development of pathomorphology.
3. Description of rivney study of pathological processes.
4. Objects and methods of research of pathomorphology.
5. Description of the basic periods of development of pathomorphology.
Gross specimen: atherosclerosis of the aorta, ulcer of the stomach, cirrhosis of the liver, arterionephrosclerosis.
Microscopic specimen: vessels gialinosis of the ovary, bronchoalveolitis, cirrhosis of the liver, hypertrophy myocardium.
Tables: level studies of pathological processes, research methods in pathoanatomy, representatives of Kiev, Kharkov, Lvov and Odessa schools of clinical pathologists, characteristic of pathomorphology course in higher medical establishments.
Slides: blood clot (micro specimen), infarction of the spleen (macro specimen), myocardial hypertrophy (macro specimen), metastases of cancer in the lung (macro specimen).
Pathomorphologyy (in applied anatomy) is the study of the structure and morphology of the tissues and cells of the body as related to disease.
The method of dissection (autopsy pathology), is the study of disease by the examination of the body after death by a pathologist. The organs and tissues are first described by their appearance at the time of dissection, then by their appearance in the microscopic examination or laboratory analysis of small representative samples of tissue taken for their diagnostic value.
Method of biopsy - biopsy /bl'opse/ [Gk, bios + opsis, view], is the removal of a small piece of living tissue from an organ or other part of the body for microscopic examination to confirm or establish a diagnosis, estimate prognosis, or follow the course of a disease.
The method of experiment (experimental design) [L, experimentum; designare, to mark out], (in research) is a study design used to test variables cause-and-effect relationships. The classic experimental design specifies an experimental group and a control group. The independent variable is administered to the experimental group and not to the control group, and both groups are measured on the same dependent variable. Subsequent experimental designs have used more groups and more measurements over longer periods of time.
Thus, a pathomorphology studies material soubstrat, or structural bases of diseases in man. There is the anatomy of ill man, "medical anatomy", integral component part of pathology (Gk. pathos - suffering) - section of medico-biologic knowledges about ill organism (etiology, pathogeny, morphology, clinic, prophylaxis and diagnostics of diseases).
Complex introduction research of pathological processes gives a possibility to consider structural and functional violations in their dialectical unity. It means that in pathology of man there are no structural violations which would not be accompanied by the functional changes and, on the other hand, in the basis of the latter the definite morphological changes of some structures lie always.
A similar dialectical interrelation between structure and function also has its reflection in practical medicine. According to its point of view, there is no «functional stage» (or disease) which is not accompanied by the structural changes in an organism.
In this connection, modern pathoanatomy deeply studies the question of etiology (close the origin of diseases), pathogeny (mechanisms of development of pathological processes). Thanks to the use of sofisticated methods of research is also develops scientifically grounded measures for timely diagnostics, adequate medical treatment and effective prophylaxis of diseases.
In the last decades, due to wide use of medical preparations, changes of environment, and changes of clinicomorphological pictures of diseases the problem of morbid anatomy has arisen. Generally, it means that the changes in the structure of morbidity and lethality arisen up due to changes of human life conditions.
In the narrowest sense of this term, it means, the change of definite disease. We distinguish spontaneous morbid anatomy (the clinicomorphological picture of disease changes due to the aging changes or constitution of a man and therapeutic one when the use of medicinal preparations lies in the basis of the noted changes). Therapeutic, or induced, morbid anatomy is observed at present in tuberculosis, leprosy, syphilisi, infectious diseases, pathology of pneumonia.
Stages of individual work in class
Study and describe gross specimen:
Atherosclerosis of aorta.Gross specimen.
The most early changes are observed in the first sections of the aorta, under the valves. With time a process spreads to the pectoral, and especially abdominal sections of the internal surface (intima) becomes uneven, plates of greyish or yellow color of irregular form occur on it.
Gradualy studies of pathological processes.Table.
Organ level- the features of development of pathological processes are studied in different organs at researches of ad osulus or with the use of light microscope. System level - the pathological changes within the limits of different systems are studied (system of circulation of blood, digestion, system of blood, and ect.). Tissue and cellular levels - pathological processes are studied by microscopic research of changes in cells and tissues of organism of man. Subcellular level - the morphological changes are studied in ultrastructure of cells (mitochondrion, lysosome, ribosome) by means of the electronic microscope. Molecular level - is based on the results of biochemical researches, which expose violation of structure of different molecules, that lie in the basis of development of «molecular diseases».
The cell — [L cella storeroom], the fundamental unit of all living tissue. Eukaryotic cells consist of a nucleus, cytoplasm, and organelles surrounded by a cytoplasmic membrane. Within the nucleus there are the nucleolus (containing RNA) and chromatin granules (containing protein and DNA) that develop into chromosomes, the determinants of hereditary characteristics. Organelles within the cytoplasm include the endo-plasmic reticulum, ribosomes, the Golgi complex, mitochondria, lysosomes, and the centrosome. Prokaryotic cells are similar but without a nucleus. The specialized nature of body tissue reflects the specialized structure and function of its constituent cells. The damage of elementary structures of the cell leads to development of its pathologies.
The cell’s body[L, cella + AS, body], the part of a cell that contains the nucleus and surrounding cytoplasm exclusive of any projections or processes, such as the axon and dendrites of a neuron or the tail of a spermatozoon. This enlarged area is concerned more with the metabolism of the cell than with a specific function. Ñell’s membrane, the outer covering of a cell, often has projecting microvilli and contains the cellular cytoplasm. The cell membrane is so thin and delicate that it is barely visible with a light microscope and can be studied in detail only with an electronic microscope. The membrane controls the exchange of materials between the cell and its environment by various processes, such as osmosis, phagocytosis, pinocytosis, and secretion. It is also called plasma membrane.
Close the damage of cells can be different:
1) physical factors: thermal, radiation (including ionizing radiation and ultraviolet radiation), gravitation, electromagnetic, changes of gas composition of the atmosphere, changes of humidity of the air and etc.;
2) chemical factors: acids, alkalis, salts of heavy metals, nonorganic and organic matters, medical preparations, pesticides, and other toxic matters;
4) extreme factors: surplus rise or, opposite, surplus decline of the functional loading.
Of course, it is not a full list of the factors which can cause damage of cells, it is necessary also to take into account that the damage can not be caused by only one isolated factor, but their combination, thus they can change in different time domains and life cycle of a cell. A character and degree of its damage depends also on force and nature of pathogenic agent, structural-functional features of an organ or tissue, and also on reactivity of the organism. In one case there are the superficial changes of reverse character.
Pathology in its simplest sense is the study of structural and functional abnormalities that are expressed as diseases of organs and systems. Classic theories of disease attributed all disorders to systemic imbalances or to noxious effects of humors on specific organs. In the 19th century, Rudolf Virchow, often referred to as the father of modern pathology, broke sharply with such traditional concepts by proposing that the basis of all diseases is injury to the smallest living unit of the body, namely, the cell. More than a century later, both clinical and experimental pathology remain rooted in Virchow's cellular pathology.
To evaluate the mechanisms of injury to the cell, it is useful to consider its global needs in a philosophical sense. As a response to the mystical or vitalistic theories of biology, teleology—the study of design or purpose in nature—was discredited as means of scientific investigation. Nevertheless, facts can only be established by observations, but teleologic thinking can be important in framing questions. As an analogy, without understanding of the goals of chess and prior knowledge that a particular computer is programmed to play it, no analysis of the machine would be likely to uncover its method of operation. Moreover, it would be futile to search for the sources of defects in the specific program or overall operating system while lacking an evaluation of the goals of the device. In this sense, it is helpful to understand the problems facing the cell and the strategies that have evolved to cope with them.
A living cell must maintain an organization capable of producing energy. Thus, the most pressing need for a free living cell, whether prokaryotic or eukaryotic, is to establish a structural and functional barrier between its internal milieu and a hostile environment.
At the same time, to survive, the cell must be able to adapt to adverse environmental conditions, such as changes in temperature, solute concentrations, or oxygen supply, the presence of noxious agents, and so on. The evolution of multicellular organisms eased the hazardous lot of individual cells by establishing a controlled extracellular environment in which temperature, oxygenation, ionic content, and nutrient supply are relatively constant. It also permitted the luxury of differentiation of cells for such widely divergent functions as nutrient storage (liver cell glycogen and adipocytes), communication (neurons), contractile activity (heart muscle), synthesis of proteins or peptides for export (liver, pancreas, and endocrine cells), absorption (intestine), and defense against foreign invaders (polymorphonuclear leukocytes, lymphocytes, and macrophages).
Cells encounter many stresses as a result of changes in their internal and external environments. The patterns of response to this stress constitute the cellular bases of disease. If an injury exceeds the adaptive capacity of the cell, it dies. A cell exposed to persistent sublethal injury has a limited repertoire of responses, the expression of which we interpret as evidence of cell injury. In general, the mammalian cell adapts to injury by conserving its resources; it decreases or ceases its differentiated functions and reverts to its ancestral, unicellular character, which is concerned with functions exclusively dedicated to its own survival. In this perspective, pathology is the study of cell injury and the expression of a preexisting capacity to adapt to such injury, on the part of either injured or intact cells.