Патологическая физиология теоретический курс = Pathological physiology theoretical course. Учебное пособие
.pdfIn the course of the experiments, each student writes down the results of research in the form of the protocol in the working journal, then performs their comparative analysis and draws conclusions on the points of the tasks posed with detailed arguments and explanations of the results obtained.
Control questions
1.The concept of the etiology and pathogenesis of diseases.
2.The concept of the pathogenicity of environmental factors. Its criteria.
3.Classification of pathogenic factors of the environment.
4.Pathogenic effect of physical factors.
5.The concept of isothermia, its species and age features in farm animals.
6.The concept of a zone of temperature comfort. Features of thermoregulation in farm animals in ordinary and extreme temperature conditions.
7.Conditions that determine the extent of the damaging effect of heat and cold on the animal organism.
8.Local and general disorders in the body under the influence of temperature factors.
9.Thermal burn and its manifestations. Mechanism of development of burn disease.
10.Hyperthermia, heat and sun stroke, their manifestations, causes and mechanism of development.
11.Local manifestations of the damaging effect of cold on the body. Frostbite, its degree, the mechanism of development.
12.The general effect of cold on the animal organism. Hypothermia. Pathogenesis of colds.
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T o p i c 3
EFFECT OF ELECTRIC CURRENT
ON ORGANISM OF ANIMALS. ELECTROTRAMS
Purpose of the lesson. Make sure that the damaging effect of electricity on the body depends on the physical parameters (type, magnitude, voltage, frequency) of the current, the resistance of tissues, the direction and duration of current flow through organs and tissues, species and individual characteristics, the reactivity state of the animal at the time of the current. To find out the mechanism of damage in the body during electrical trauma (electrochemical, electrothermal and electromechanical action of the current) and the general reaction of the body to electric current.
Tasks.
1.Determine the threshold of stimulation by an electric current with a frequency of 50 Hz and the resistance of tissues in an animal at contacts imposed on dry hair, dry and moist skin, subcutaneous tissue of the hind limbs, the occipital region and the mucosa of the upper lip (electric current passes through the brain) Right pelvic and left thoracic extremities (current passes through the heart).
2.To ascertain whether the sensitivity of the animal to the action of electric current changes with the decrease in the reactivity of the organism (for example, caused by anesthesia).
3.Determine the nature and characteristics of damage to tissues through which current flows, and general disorders in the body of various animal species during electrical injury. Explain their pathogenesis.
Research Methodology
1. An animal (a dog, a rabbit or a rat) under a light narcosis is fixated on an operating table. The rheostat with a movable
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contact in the left end position, when there is no electric current in the circuit, is connected to an alternating current network with a frequency of 50 Hz and a voltage of 220 V. Needle electrodes connected through a rheostat to the network, first apply to dry hair, dry cut and then moistened with sodium chloride solutionskin of the pelvic limbs, and the gradual movement of the rheostat clamp increase the voltage until the first reaction of the animal to the action of electricity (muscle contraction, anxiety). For each position of the electrodes, determine the minimum voltage causing the reaction of the animal, and record the data in the protocol. In the same sequence, establish the threshold of electroporability of the animal when electrodes are inserted under the skin (previously disinfected the injection site and electrodes with alcohol swabs) of both pelvic extremities in the thigh region. Then one of the electrodes is inserted under the skin of the occipital region, and the second one is applied to the oral mucosa (the current is passed through the brain). In conclusion, the electrodes are inserted under the skin of the right pelvic and left thoracic extremities (electric current passes through the heart).
N o t e : After each experiment, the movable contact of the rheostat must be necessarily put to the left extreme position in order to avoid injury to the animal in the next experiment.
2.For studying the value of the reactivity of the organism in electric trauma, determine the lowest voltage of the current causing a slight twitching of the muscles, the application of electrodes on the dry skin of the hind legs of the animal. Then repeat the experiment in conditions of deep drug anesthesia (the type and dose of the drug should be chosen taking into account the type and weight of the experimental animal).
3.For the experimental study of local and general manifestations of the pathogenic action of electricity on the body, a current of 220 V is passed through various tissues and organs (skin, muscles and bones of the hind limbs, brain, heart) of the anesthetizedanimal (frog, mouse, rabbit, dog) A few seconds. Identify
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and describe in detail the nature and characteristics of morphological and functional disorders in the tissues and organs of the animal.
When the current is passed through the animal's body along the diagonal, the right pelvic – left thoracic limbsopen the thorax and determine the functional state of the heartimmediately after disconnecting the current and stopping the breathing.
Control questions
1.Electric energy as a potential source of damage to agricultural animals in the conditions of industrialization of livestock.
2.Varieties of electricity used in animal husbandry and veterinary medicine. Their physical characteristics.
3.The main factors that determine the pathogenic effect of electric current on the animal organism.
4.Local action of electric current on the tissue.
5.The general effect of electric current on the animal's organism.
6.Species and age features of electro-sensitivity and electrovulnerability of agricultural animals.
T o p i c 4
DELETERIOUS ACTION OF CHEMICAL
AND BIOLOGICAL AGENTS
ON THE ORGANISM. INTOXICATION
Purpose of the lesson. To study the mechanism and general patterns of pathological changes in the animal's organism that arise under the influence of various chemical and biological pathogenic factors. To get acquainted with the clinical picture of acute poisoning of animals.
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Tasks.
1.Find out is there any damaging effects of solutions of sulfuric acid and sodium hydroxide with weak, moderate and high concentrations on body tissues when applied to the skin of the animal for a very short and longer time. Explain the mechanism and characteristics of the damage of biological tissues with acids and alkalis, depending on their concentration and duration of action.
2.Determine whether there are any abnormalities in the life of the animal when the body is exposed of toxic doses of phenol, organophosphorus compounds, atropine, chloroform. Explain the ways and mechanism of the penetration and action of these substances, especially the clinical picture of the poisoning caused by them.
3.Determine what changes in the body are caused by the introduction of an animal into the blood of an extract from intestinal helminths or microbial toxins.
Based on the results of the research, a conclusion is made about the etiological role of chemical and biological factors, mechanisms and patterns of their pathogenic action on the animal's organism.
Research Methodology
1. On a small area of the skin of the animal's back with a glass rod, apply a drop of a weak (0.5%) solution of sulfuric acid, observing the reaction of the animal, and after 2-3 seconds remove it with a piece of cotton wool soaked in water. After that, carefully examine the site of the acid, evaluate the structural and functional state of the skin. Then apply the same solution to another area and leave it for a longer time (1-2 minutes). After removal of the stimulus, again determine the skin condition, noting its structural integrity, density, elasticity, etc. In the same way, successively test the action of 5 and 30-40% solutions of sulfuric acid, as well as 0.5, 5 and 30-40% solutions of caustic soda. Pay
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attention to the general reaction of the animal to irritations, establish the nature and extent of damage to the skin.
2.Take 5 animals (mice) and, having determined the initial physiological state (reflex reactions, behavior, frequency and amplitude of respiration, cardiac contractions, etc.), enter 0.5 ml subcutaneously: the first – 1% solution of phenol (Carbolic acid), the second – chlorophos or dichlorvos at the same concentration, the third – 0.1% solution of atropine sulfate, the fourth – 0.85% solution of sodium chloride (control). Place the fifth animal under a glass cap and put a piece of cotton wool soaked in chloroform. Closely monitor the condition of animals, periodically (every 1-2 minutes) by recording clinical and physiological parameters.
3.The effect of toxins of biological origin on the body is studied in an experiment on a dog or rabbit by injecting an animal from the parasitic worm into the blood.
To prepare extracts from helminths, intestinal parasites are collected during the de-worming of animals (for example, ascarids from dogs), washed with warm physiological saline and a sample of fresh mass of helminths is grounded in a mortar. The resulting homogenate is filled with distilled water at a rate of 2 ml/g, mixed thoroughly and after 20-30 minutes filtered first through a double layer of gauze, then through a filter paper (the filtrate contains various poisonous substances produced by parasitic worms). The extract thus obtained is injected to the experimental animal intravenously in the doxes with 2-3 ml/kg and observe the development of the clinical picture of the general poisoning of the organism, paying attention to changes in the function of the nervous, cardiovascular and respiratory systems.
The most significant violations when biological toxins enter the body are noted from the side of the cardiovascular system. Therefore, for a more detailed study of the nature and extent of hemodynamic disturbances can record blood pressure, heart rate, the magnitude of the ventricular amplitude and simultaneously record on a kymograph via a cannula inserted into the carotid artery, in an animal under anesthesia.
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Control questions
1.What chemical agents are capable of having a pathogenic effect on the animal organism? What are their origins and properties?
2.What chemicals are called poisons?
3.How are toxic substances classified, by what principles, and for what purpose?
4.What are the ways of penetration and the general mechanism of the damaging effect on the body of chemical poisons?
5.What is intoxication and autointoxication, what are their most typical manifestations?
6.What biological factors can cause pathological processes in the body of animals?
7.What is the mechanism of the damaging effect on the body of bacteria, viruses, pathogenic fungi, protozoa, parasitic worms, arthropods?
T o p i c 5
PATHOGENIC ACTION ON THE ORGANISM OF ANIMALS OF DECREASED ATMOSPHERIC PRESSURE. SIGNIFICANCE OF THE REACTIVITY OF THE ORGANISM IN THE DEVELOPMENT OF PATHOLOGICAL PROCESSES
Purpose of the lesson. By experimental modeling of altitude sickness in animals with different physiological states, study the mechanisms and general patterns of disturbance of body functions with a sharp decrease in atmospheric pressure, to reveal the importance of the animal's reactivity and its directed changes in the development of the disease.
Tasks.
1. To determine the nature, extent and sequence of impaired functions in the animal's body under the influence of low baro-
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metric pressure of different sizes. Explain the causes and mechanism of the emergence of these phenomena, to make a conclusion about the pathogenic role of low atmospheric pressure.
2. To elucidate the peculiarities of the manifestation of the response and disruption of the vital activity of the organism in the pathogenic action of atmospheric pressure in adult animals under normal conditions, in the suppression of the function of the central nervous system (anesthesia), starvation, physical overfatigue, and in newborn animals.
Make a conclusion about the importance of the organism's reactivity in the development of pathological processes.
Research Methodology
1.Determine the initial physiological status (general condition, mobility and behavioral responses, frequency and depth of respiratory movements, the state of visible mucous membranes, etc.) in an animal (mouse, rat or guinea pig), place it under a glass bell, hermetically sealed to a special plate-stand, equipped with a vacuum gauge, and gradually suck air from under the bell with a vacuum pump, continuing to observe the state of the animal. According to the vacuum gauge, at which value of atmospheric pressure (at what height above sea level) respiratory disorders, blood supply of tissues, neural-reflex activity, coma and death occur in the experimental animal.
2.Undertake reduced atmospheric pressure (similar technology) for four adults and one newborn animal, which is isolated from adults during the experiment.
One of the adult animals 2-3 days before the experiment is not given food (you can drink water), the second immediately before the experiment is forced to swim until complete muscle fatigue (about 5 minutes) in warm water (4-25 ° C), the third is anesthetized by subcutaneous injection 10% urethane solution at a rate of 1.5 ml per 100 g of animal weight. The fourth animal serves as a control.
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Pumping air from the vacuum unit, observe the physiological state of animals, determine the timing of the emergence of protective-compensatory and pathological phenomena. With the onset of death of the control animal, stop sucking air, let air in under the bell, extract the experimental animals, determine and compare their physiological state.
For a broader understanding of the value of the reactivity of the organism in the development of pathological processes, experience is repeated on other species of animals (for example, on frogs).
Control questions
1.Physical pathogenic factors.
2.Influence of low and high atmospheric pressure on the
body.
3.The main mechanisms of disease development.
4.Pathogenesis of altitude and caisson disease.
5.The concept of the reactivity of the organism. Types of reactivity.
6.The main factors that determine the reactivity of the body.
7.The importance of reactivity in the development of pathological processes.
8.Directional change in the reactivity of the organism as the most important means of preventing and treating diseases.
T o p i c 6
IMMUNE REACTIVITY OF THE ORGANISM AND ITS VALUE IN PATHOLOGY. CELLULAR PHENOMENA
IN IMMUNITY RESPONSES. PHAGOCYTOSIS
Purpose of the lesson. To clarify the role of cellular immunity factors in the protective reactions of the organism to pathogenic irritations, the essence and mechanism of phagocytosis.
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Tasks.
1.To determine whether the leukocytes interact with and get into the blood by microorganisms. Name the noted phenomenon and explain what other cells, what organs and systems of the body have this property.
2.To ascertain whether the animal captures and kills foreign particles (for example, heterogeneous erythrocytes) trapped in the abdominal cavity by phagocytes; How the amount and activity of phagocytes in the abdominal cavity changes in response to the introduction of foreign proteins (with the development of the inflammatory process).
3.To find out whether the phagocytic activity of the cells of the reticuloendothelial system in the animal is also altered in the suppression of the central nervous system (anesthesia). To make a conclusion about the role of the nervous system in the immunobiological, reactivity of the organism.
Research Methodology
1.Pour 0.5 ml of freshly received blood into a centrifuge tube and add 0.1 ml of a suspension of avirulent Staphylococcus strain prepared according to the optical turbidity standard with a concentration of 2 billion microbial bodies in 1 ml. The contents of the tube are mixed and placed in a thermostat with a temperature of 38° C for 1 hour, then centrifuged at 3,000 rpm for 3 minutes. From the upper (leukocyte) layer of the sediment, prepare smears, dry them in air and fix for 3 to 5 minutes with methyl alcohol. Stain byRomanovsky-Giemsa for 20-25 minutes and study under a microscope.
To count 100 phagocytes, while determining the phagocytic number, that is, the number of leukocytes participating in phagocytosis, expressed as a percentage, and the phagocytic activity (the number of microbes, which on average accounts for one phagocyte).
2.For 36-40 hours before the study of guinea pig or rat, 5- 10 ml of sterile meat-peptone broth (1% peptone) and 5 ml of
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