Патологическая физиология теоретический курс = Pathological physiology theoretical course. Учебное пособие
.pdftory work using a virtual laboratory workshop, solving and discussing situational tasks in pathological physiology. Description, analysis and analysis of pathogenesis schemes, classification of pathophysiological processes.
Performing laboratory work on pathological physiology requires creative work of students and involves the acquisition of students' research skills.
This manual outlines the basic, indicative laboratory work. In laboratory classes and during preparation to it, the student is obliged to use the following textbooks and teaching aids as compulsory literature and to orient oneself to them when performing assignments:
1.Baymatov V.N. Manual on pathological physiology: Textbook. SPb.: Publishing House "Lan’", 2013. 352 p.
2.Lyutinsky, S.I. Manual on the pathological physiology of farm animals / S.I. Lyutinsky, V.S. Stepin. Moscow: Kolos, 2001.
3.Savoy, A.G. Pathological physiology. / A.G. Savoy, V.N. Baymatov, V.M. Meshkov. Moscow: Coloss, 2008.
The final stage of the lesson is the determination of the total level of knowledge. Objective assessment of the student's mastery of the material of each lesson (the total level of knowledge) allows the teacher to constantly see the level of each student and conduct individual work with him, thereby improving the quality of teaching.
T o p i c 1
SUBJECT, TASKS AND METHODS OF PATHOLOGICAL
PHYSIOLOGY. THE IMPORTANCE
OF THE EXPERIMENT
IN PATHOPHYSIOLOGICAL RESEARCHES
Purpose of the lesson. To study the subject and tasks of pathological physiology of farm animals, determine its place in the system of veterinary education, the tasks of the pathophysiol-
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ogy manual. To get acquainted with modern methods of studying pathological processes and functions of a sick organism, the basic equipment used in pathophysiological studies. Analyze the basic principles of the experimental approach to cognition of the mechanisms and patterns of disturbance and restoration of the functions of the animal organism, the modeling of pathological processes.
Tasks.
1.To determine a subject of pathological physiology of animals, its importance in the formation of a veterinarian, the relationship and correlation of theory and practice in the cognition of the vital activity of a sick organism.
2.List and briefly describe the main methods of pathophysiological studies. What specific tasks can each of these methods solve, what are their capabilities?
3.To study the basic instruments and laboratory equipment, surgical instruments, medications, suture and dressing materials used in observations and experiments on animals, methods of preparing them for work.
4.To determine the nature and extent of changes in the frequency and strength of cardiac contractions in an animal under various effects: a) irritation of the vagosympathetic trunk and intestinal receptors; B) the effect on the heart of cold and heat, adrenaline and acetylcholine; C) violation of the function of the conduction system of the heart by imposing ligatures (Stannius' experience).
Based on the obtained results, a conclusion is made about the significance of the experimental method in pathophysiological studies.
Research Methodology
When starting the first and second tasks of the topic, it is important to disclose the essence of pathological physiology as a science, its place and role in the system of higher veterinary edu-
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cation and the formation of medical thinking, the main tasks facing the pathological physiology of farm animals in the light of modern requirements, the importance of the workshop in the process of studying the discipline, its general goals and specific tasks, to understand the methodology and techniques of pathophysiological studies.
The third task involves the study of the structure and the principle of the action of the main equipment, instruments and other material and technical means of clinical and experimental significance, most commonly used in pathophysiological studies, familiarity with the general rules for their preparation for usage and operation, the conditions for the correct and safe use of various devices and tools.
Before carrying out this work, students receive an introductory safety instruction by the teacher, after which each signifies in a special journal.
To reveal the role of the experimental approach to the study of pathological processes and mastering the technique of experiment (4th task), it is necessary to conduct an experiment on animals (frogs).
Place the animal with abdomen up on the dissection board, open the thorax and expose the heart. Prepare for work and connect to the facility installation for graphic recording of heartbeats on the kymograph (cardiograph).
Enable the recording, and, without affecting the object, visually observe the activity of the heart, analyze the resulting cardiogram (determine the frequency, rhythm and sequence of contractions of various parts of the heart, the duration of the heart cycle, its phases, the magnitude of the ventricular amplitude). Then, carrying out those or other effects specified in the task, determine the nature and degree of changes in the functions of the heart, especially its response to the violation of various conditions.
As a result, students will receive experimental models of individual forms of cardiac dysfunction (tachycardia and bradycar-
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dia of different etiology, complete transverse dissociation). When analyzing the obtained data, it is necessary to explain which pathogenic factors can cause similar pathological reactions of the organ in natural conditions, and under what diseases they are observed.
At the end of the lesson, students get acquainted with the rules for documenting experimental and clinical studies, writing a research protocol as a scientific document.
Experimental models to study the physiology, pathophysiology
Pathological physiology of animals is the main discipline in the studying of a veterinarian, because it lays the foundation for all clinical disciplines. The experiment is the main method of pathophysiology.
The experiment in the broadest definition of the word is the active influence of man on nature and artificial reproduction of the different phenomena. The peculiarity of pathophysiological experiment is to reproduce on laboratory animals of experimental disease models with the aim of establishing the mechanisms of their occurrence, development and outcome in live-stock animals and companion animals.
The experimental model of the disease is the synthetic simulation of disease in laboratory animals, which has certain features of the corresponding disease of domestic animals.
The experiment gives an opportunity to observe and study the disease from its beginning to its outcome, which is impossible in the clinic. It is possible to control the environmental conditions influencing the course of the disease, as well as the original state of animals that are the object of experience. Experiment is the only way of studying such effects on the organism, the use of which is unacceptable in the clinic (trauma, transplantation of tumors, irradiation). Experimental studies give an objective material for the designing of scientific theories.
There are an acute and chronic experiments.
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Acute experiment (vivisection) is based on surgical intervention in the animal organism. It allows to study acute diseases, such as shock, collapse, crush syndrome, acute respiratory failure, circulation, kidneys and etc.
A chronic experiment is long. It provides an opportunity to study the dynamics of disease development. It is used for modeling chronic diseases, such as atherosclerosis, hypertension, diabetes mellitus, peptic ulcer etc.
Stages of the pathophysiological experiment:
1.Designing the experiment.
2.Modeling of normal and pathological processes.
3.Observation: obtaining information about changes in the organism of experimental animals.
4.Analysis of the obtained results.
Let's consider each stage of the pathophysiological experiment in more detail.
Designing an experiment – this stage of experimental research involves:
a)evaluate the hypothesis;
b)setting on objective and research task;
c)sampling formation (species, age, sex of animals);
d)experiment should be designed with later statistical tests in mind;
e)determining the amount of research.
There are various methods of modeling disease. Dissection method. By dissection of the liver, hepatic failure
is simulated, kidney – acute renal failure, pancreas – diabetes mellitus, pituitary – panhypopituitarism etc.
Method of destruction. Using surgical treatment (cutting of the nerves, destruction of nerve centers, tissue damage), physical factors (ionizing radiation, temperature etc.), chemical agents (poisons, inhibitors), immune effects (antibodies, tissue serum).
Overload method. Inducing functional overwork of the highest centers of the CNS, neurosis is modulated; creating an artificial heart defects – reproduce heart failure; the introduction
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of large quantities of cholesterol and NaCl model respectively atherosclerosis and arterial hypertension.
Creating deficiency. Creating a deficiencyof oxygen in the chamber, hypoxia is simulated; applying low-vitamins diets, get a- an hypovitaminosis, insufficiency of antioxidants.
The method of dysfunction of the nervous and hormonal regulation. Widely used irritation or damage to nerve structures, pharmacological intervention in the exchange of neurotransmitters, the introduction of a large number of hormones or their analogues.
Method of creating barriers. Bandaging blood vessels, simulate myocardial infarction and arterial hypertension, and the common bile duct – mechanical jaundice. Introduction to the coronary vessels of emboli is used to reproduce myocardial infarction.
Method of exogenous induction. Introduction into the body or effect on it by factors that are specific pathogens of the disease. To simulate all infectious diseases, malignant tumors, allergies.
The method of transplantation is used in the study of malignant tumors, sclerotic vascular lesions.
The method of exteriorization is the study of pathological processes outside the body: in tissue cultures, on isolated organs. Used in the study of tumor growth, atherosclerosis, allergic reactions.
The methods used to obtain information on changes in the organism of experimental animals are:
1.Morphological (macroscopic study, light and electron microscopy, etc.).
2.Functional (registration of muscle contractions, electrocardiography, encephalography, recording of spirograms, determination of oxygen consumption, etc.).
3.Biochemical (determination of the concentration of substrates, hormones, electrolytes, metabolic products, enzyme activity).
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4. Immunological (determination of antibody titer, blast transformation of lymphocytes, etc.).
With the help of these methods, information on changes in the molecular, subcellular, cellular, tissue, organ, systemic levels and at the level of the organism as a whole is obtained.
In the experimental studies, the following methods of analysis can be used:
1.Mathematical methods. These include statistical methods that allow us to identify the correlation between different groups of indicators; methods of mathematical modeling.
2.Comparative methods of analysis:
a)phylogenetic – modeling and comparison of pathological processes in species of animals that are at different levels of evolutionary development;
b)ontogenetic – study and comparison of pathological processes in animals at different stages of their individual development;
c)topographic-anatomical – study and comparison of pathological processes in different organs, in different parts of the same organ, in different cells.
3. The method of combining pathogenic effects involves the use of different combinations of pathogenic influences. Under these conditions, it is sometimes possible to identify such properties of the pathological process that remain hidden if only one factor acts on the body.
4. Method of corrective influences. They model the pathological process, and then try to eliminate some of its manifestations by the introduction of certain substances or other influences.
Conclusion: as a result of a pathophysiological experiment, veterinary science receives exhaustive knowledge about the properties of the organism and its vital activity, disease, pathological reaction, processes and states, determining the main etiological and pathogenetic principles of prevention, diagnosis and treatment of diseases.
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Control questions
1.What are the main tasks of the manual on pathological physiology?
2.What are the main methodological approaches to the study of pathological processes and functional changes in a diseased organism you know?
3.What is the essence of the method of observation, with the help of which methodical methods and means it is carried out in pathophysiological studies?
4.What is the essence of the experimental method? What are its fundamental differences from the method of observation, and significance in pathological physiology?
5.What methods and means of experimental study of pathological processes do you know?
6.What are the main principles of experimental modeling of pathological processes and diseases?
7.What are the forms and procedure for documenting the results of scientific research in pathological physiology?
8What is the experimental protocol? What is its structure and composition?
GENERAL NOSOLOGY.
ETIOLOGY AND PATHOGENESIS
T o p i c 2
PATHOGENIC ACTION OF HIGH
AND LOW TEMPERATURE ON THE ANIMAL ORGANISM: LOCAL AND GENERAL DAMAGES
Purpose of the lesson. In experiments using local thermal action, general overheating and cooling of the body, to study the
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causes and mechanism of development in animals of thermal burn and hyperthermia, frostbite and hypothermia. To clarify the role of high and low temperature of the environment in the emergence of these pathological processes.
Tasks.
1.To determine what local and general disturbances occur in the animal's body when the body is exposed to a hot object for a short time (for example, water heated to 85-90° C).
2.Determine by what protective-adaptive and pathological reactions of the organism a prolonged stay of the animal in anenvironment with a high temperature (50-60° C) is accompanied, what processes of vital activity and in what sequence are violated in these conditions.
3.Find out what local and general disorders occur in the body when the animal stays in anenvironment with a low temperature (below 0° C). Determine the dependence of the rate of development and the degree of disturbances on the humidity of the environment and the surface of the animal's body.
Research Methodology
1. In a white rabbit, on a small portion of the inner surface of the ear the hair is cut off. To determine the general physiological condition of the animal, carefully examine the ears in the transmitted light, note the color, density and elasticity, pain sensitivity, the state of the vascular network, etc. Then attach the asbestos paper to the inner surface of the ear in the shape of the ear so that the hole in it is above the shaved section. Unprotected by asbestos, the surface of the ear isbrought into contact with a test tube with hot water (85-90° C) for 2-3 seconds while simultaneously monitoring the general state and reaction of the animal. Then, remove the tube and asbestos paper and reassess the condition of the auricle on the fired and protected areas, paying special attention to the pathological changes that have arisen. In the clinical picture, establish the degree of burn.
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2.To determine the initial physiological state (temperature in the rectum, respiratory rate, the state of the external covers, mucous membranes, motor reactions, etc.) of the rat or guinea pig, place the animal in a 0.5-1.0 l glass jar with cardboard padding on the bottom and close the lid. Through the holes in the lid in the jar, enter a wide glass tube for ventilation and a thermometer. Then put the can with the animal in a vessel with warm water and gradually pour hot, or into a water bath. Bring the temperature of the air in the can to 50-60° C and keep it at this level, continuing to monitor the condition of the animal and periodically (every 3-5 minutes) to register rectal temperature, respiratory rate and other physiological parameters.
3.During the experiment, determine the overall and local effect on the body of low temperature and the dependence of the damaging effect of cold on the humidity of the environment. To this end, take two animals (white mice or rats), establish their initial physiological state. One of them should be lowered into warm water, so that the skin and hairline is moistened, and then into a small glass jar with a damp cardboard or felt pad on the bottom. The second animal is placed in the same jar, but with a dry lining. Close the jars with a lid, in the opening of which a wide glass tube and a thermometer with a scale of +40 to -20° C were placed, put in a tank (a bucket) with a cooling mixture (2 parts of snow + 1 part of sodium chloride) so that the jar was immersed in snowto the top edge. Pay attention to the fact that the temperature in thejarfalls fairly quickly to 0° C or lower (in a jar with a wet animal, air has a high humidity due to the evaporation of moisture from the surface of the body).
From the moment of dipping the jars into the cooling mixture, carefully monitor the condition of the animals, paying special attention to the peripheral parts of the body (paws, ears, tail, muzzle), monitor their behavior, determine the respiratory rate and body temperature every 3 minutes. Experimentcontinues until the death of one of the animals.
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