Общая патологическая анатомия животных = Introduction to the pathological anatomy of animals. Учебно-методическое пособие

PEOPLES’ FRIENDSHIP UNIVERSITY OF RUSSIA

AGRARIAN TECHNOLOGICAL INSTITUTE

Department of Veterinary Medicine

INTRODUCTION

TO THE PATHOLOGICAL ANATOMY OFANIMALS

Moscow

Peoples’ Friendship University of Russia

2018

Definition of the subject, purpose and objectives

Pathological anatomy is a science that studies pathomorphology of the disease at various morphological levels. So, it is the science of morphological changes in the organs and tissues of animals and humans in various diseases. This is the anatomy and histology of the diseased organism.

The purpose of the discipline: to study and disclosure of the emergence and development of morphological changes in the organs and tissues of animals in various diseases, as well as the establishment of causes of death.

Objectives of pathological anatomy:

1.Formation of the theory of veterinary medicine.

2.Implementation of clinical and morphological studies to establish the diagnosis and improve it.

3.Serve as a morphological basis for practical veterinary medicine.

4.Serve as a source of practical and theoretical knowledge in the field of veterinary sanitary expertise.

5.To evaluate the effectiveness of methods of treatment of animals.

6.To serve as a source of practical and theoretical knowledge when conducting forensic veterinary examination.

The object of the study of pathological anatomy are corpses of animals, pathological material obtained at autopsy, material obtained during surgical operations, material obtained as a result of the experiment, biopsy material.

Structure of pathological anatomy:

1.General pathological anatomy

2.Private pathological anatomy

3.Clinical pathological anatomy (sectional course)

General pathological anatomy is a science that studies general pathological processes, states, and also typical pathological processes.

In this section, the main general pathological processes are studied:

1.Alteration (damage): dystrophy, atrophy, necrosis.

2.Dyscirculation (violation of blood, lymph, fluid in the body): arterial and venous hyperemia, ischemia, stasis, hemorrhagia, plasmorrhagia, thrombosis, embolism, infarctions, edema, dropsy, excision, development of collateral (shunts).

3.Inflammation.

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4.Compensatory-regenerative processes: hypertrophy, hyperplasia, regeneration, wound healing, organization, atrophy, tissue reconstruction, histological accommodation.

5.Tumor growth.

Private pathological anatomy studies issues related to individual nosological units, that is, individual diseases.

This section includes:

1.Organopathomorphology

2.Pathomorphology of infectious diseases

3.Pathomorphology of invasive diseases

4.Pathomorphology of neonatal diseases

5.Pathomorphology of intoxications

6.Radiation pathology

7.Pathomorphology of malformations (teratomorph)

Clinical pathological anatomy (sectional course) - is intended for:

1.Practical skills in the autopsy of dead animals

2.Patho-anatomical diagnosis

3.Clinico-anatomical comparison and drawing conclusions about the causes of death of the animal.

Levels of studying pathological anatomy of animals:

1.Molecular (histochemistry, cytochemistry)

2.Subcellular - the study of ultrastructure of cells (organelles) using an electron microscope

3.Cellular and tissue - the study of the structure of tissues, cells and intercellular space

4.Organic - the study of changes in individual organs with the help of microand macroscopy.

5.Systematic - studying changes in organ systems

6.Organism - the study of pathology within the whole organism in the interrelationship of all its organs and systems.

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Death. The doctrine of death (thanatology). Tanatogenesis.

Death (lat. mors, tanatos) - irreversible cessation of metabolism and vital functions of the body. This is the inevitable cessation of the natural life cycle of an animal or human. With the onset of death, the living organism turns into a corpse, a dead body (lat. cadaver).

The etiology of death: death is of two types - natural and pathological (premature).

Natural death occurs as a result of old age due to the gradual deterioration of the body. Natural death is an exception to the rule, it does not exist in nature.

The theory of aging and dying:

1.Wear theory

2.Gene-regulatory theory

3.The neuroendocrine theory

4.Immune theory-theory of immune treason

5.Molecular-genetic theory.

6.The theory of the accumulation of errors. Pathological death is non-violent and violent.

Nonviolent pathological death is a premature pathological death

that develops under the influence of adverse factors of the external or internal environment, most often from diseases.

It may be:

1.With clinically expressed manifestations-as a result of disease, pathological condition, pathological process, trauma, etc.

2.Sudden, unexpectred, premature-without visible previous clinical manifestations of the disease (heart attack, stroke, rupture of the aortic aneurysm, etc.).

Types of non-violent death: from CVS diseases, from RS diseases, from diseases of the NS, from diseases of the gastrointestinal tract, from diseases of the GUS, from infectious diseases, during pregnancy and childbirth, etc.

Violent death – pathological death resulting from intentional or unintentional exposure to third parties:

1.unintentional

2.intentional

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Types of violent death:

1.Murder / slaughter

2.From mechanical damage

3.From mechanical asphyxia (from suffocation)

4.From poisoning

5.From the action of extreme temperatures

6.From the action of electricity

7.Changes in atmospheric pressure

8.From the action of radiant energy

Tanatogenesis is the process of death. Death in the animal and human body occurs gradually, it is a process.

This process includes five main stages:

1.Preagony

2.Terminal pause

3.Agony

4.Clinical death

5.Biological death

Agony (from Greek. agon – the struggle) – the specific condition of the organism, namely an initial stage in its fight against dying. It is characterized by the mobilization of all available protective-adaptive and compensatory mechanisms that counteract pathogenetic mechanisms. Agony is characterized by a significant increase in blood pressure, increased CVS and RS, increased motor activity, in the CNS excitation processes prevail over deceleration. Further, there is a depletion of protective and compensatory forces and in the central nervous system braking develops. Against this background, hypoxia increases and the functioning of all systems decreases sharply. Bradycardia, bradypnea, reduced blood pressure develop. The animal takes a lateral position, many reflexes disappear.

Clinical death develops: deep inhibition of CNS activity in connection with the stop of blood circulation, breathing and hypoxia of the brain of the animal. At this stage, resuscitation is possible, but for a short time (5 – 6 min.).

If resuscitation does not occur biological death, the body turns into a corpse. Irreversible morphofunctional changes in the body as a result of autolysis develop (lysosomal enzymes play a major role in this process). In the corpse there are early and late corpse changes (they are

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secondary and tertiary, respectively). Primary cadaveric changes occur during agony and clinical death.

Causes of death:

There are main (determining) and immediate (nearest) causes. The main cause is the main disease or other cause that caused death through complications. The immediate cause is directly related to the mechanism of death. There may be a lot of main causes, the immediate causes of death are only two – paralysis of the vasomotor center and paralysis of the respiratory center.

Vital triangle (rule) M. F. K. Bichat:

A living organism, dying, turns into a corpse, if there is a death of the brain, cardiac arrest (i.e. paralysis of the vasomotor center) and respiratory arrest (i.e. paralysis of the respiratory center).

Corpse changes

Corpse changes are divided into early (secondary) and late (tertiary).

Classification of the early (secondary) post-mortem changes:

1.Postmortem cooling (algor mortis)

2.Postmortem rigidity (rigor Mortis)

3.Cadaveric drying

4.The redistribution of blood

5.Livor Mortis (mortis livoris)

-stage of hypostasis (hypostasis)

-stage of imbibition (imbibitio)

Corpse cooling (algor mortis) – cooling of the corpse according to the physical laws to the ambient temperature. At a temperature below zero the corpse freezes.

Cooling rate depends on:

-ambient temperature

-air humidity

-fatness of the animal

-cause of death

The rules of the cooling of the corpse: the first day at an ambient temperature of +20 degrees cooling occurs at a rate of 1 degree per hour. On the second day, the cooling rate is 0.2 degrees per hour.

A dead body cools more slowly, if:

1.the animal was well-fed

2.the animal fell from purulent-septic or similar diseases The corpse cools faster if:

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1.death came from hypothermia

2.from a poisoning

Postmortem rigidity (rigor Mortis) – a special condition of the corpse, characterized by a powerful hardening of the muscles. The basis of this process are biochemical reactions occurring in the corpse. As a result of hypoxia and ATP deficiency in the muscles of the corpse, the breakdown of carbohydrates follows the path of anaerobic glycolysis, i.e. not to H2O and CO2, but to intermediate products – lactic acid (lactate). The accumulation of lactate leads to the formation of a persistent actin-myosin complex, which is externally manifested in the form of rigor Mortis. Rigor Mortis occurs after 6 to 12 hours and reaches a maximum of 24 hours after death, then weakens and disappears after 24 to 48 hours after death. In small animals rigor Mortis disappears after 3 to 6 hours.

Rigor Mortis develops in the following sequence: the first the muscles of the head and neck and dewlap, thoracic limb, pelvic limb chill. Large muscles undergo rigor Mortis later than anything else, but rigor is the most persistent. The rigor disappears in the same order.

Rigor Mortis is pronounced in well-fed animals after severe agony, and when the animal died from some infectious diseases (tetanus). Rigor is not pronounced in septic diseases and at exhaustion.

Corpse drying – evaporation of liquid from the surface of the corpse, visible mucous membranes and internal environments. Drying of the corpse begins with the visible mucous membranes and eyes (if they were open at the time of death). At first, the cornea and the protein membrane dries up, after 6 hours the cornea becomes cloudy, and the protein membrane dries on both sides of the pupil in the form of graywhite triangles – spots La Roche. Then other mucous membranes and skin dry up. They become dense (sometimes they look like parchment paper).

Redistribution of blood – flow of blood in the lower veins of the body under the action of gravity. Then there is a process of blood clotting, further on the components of the blood begin to come out into the surrounding tissues, cadaveric spots develop.

Cadaveric spots – a process of redistribution of blood in the corpse, associated with a change in its physical and chemical properties and subsequent sweating into the surrounding tissue. Cadaveric spots begin to appear 2-3 hours after death, reaching a maximum of 12 hours.

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Cadaveric spots are in 2 stages:

1.Hypostases – the accumulation of blood in the underlying veins of the body. Hypostases develop immediately after the death of the animal. Characterized by an overflow of the venous network with giving the parts of the corpse the appropriate color. Normally it is dark red, cherry spots with a bluish tint. When monoxide poisoning hypostase it is bright scarlet, in cases of poisoning with hydrogen sulfide it is black, with death from asphyxia – rich and blue-purple, with nitrate toxicity it is chocolate. If in the stage of hypostasis the corpse is moved, the spots will also change its location. Internal hypostase is the result of internal leakage, that is, effusion of bloody fluid in the natural serous cavities of the body. Unlike blood, it – "paint blood", transparent liquid containing hemolized erythrocytes. Hypostases are well expressed at death from asphyxia, in well-fed animals. They are poorly expressed in depleted and bloodless animals.

2.Imbibition is the impregnation of the tissues of the corpse with blood elements. It occurs due to a sharp increase in vascular porosity with the release of hemolysis products of red blood cells in the tissue. It starts 18 hours after death. Hemolysis products penetrate through the wall of blood vessels and impregnate the tissue. Along and around the blood vessels cherry lane appears. Veins contour in the network view. The spots do not pale when pressed. Decomposition stains are dull green in connection with a change of hemoglobinogenic pigments.

Classification and characteristics of late (tertiary) post-mortem changes:

1.Corpse decomposition / decay

2.Mummification

3.Skeletization

4.Adipoceration

5.Peat tanning

Tertiary cadaveric changes develop on 2-3 days after death. It depends on the location of the body and the cause of death. The result of late corpse changes is either decomposition of the corpse, or its preservation. If there is enough oxygen, the ambient temperature is positive, and there is sufficient humidity, then there is corpse decomposition. It occurs under the action of its own enzymes (proteolytic enzymes of lysosomes), that is, autolysis develops. The first signs of decay develop on the second day after death with the

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formation of cadaveric greenery in the groin. After 3-5 days cadaveric greens is spread on the skin. Hydrogen sulfide, methane, mercaptans, indole, skatole, etc. allocate. Gases impregnate tissues of the body, crepitus develops. Then on the surface of the corpse bubbles are formed-corpse emphysema. There is a strong smell. Further, the putrid bubbles burst and soft tissues turn into a stinking gray-green mush. Exposed bones and ligaments – these tissues can be stored for a very long time. If the decomposition of the corpse is very fast, then after a while the bones are exposed and the corpse is skeletonized.

If the humidity of the environment is low (dry soil, dry room), the soft tissue dry, the skin becomes like parchment, dark brown. There is a loss of the total mass of the corpse to 90%. It's mummification.

When the corpse is in the soil with an abundance of humic acids, it is preserved with the tanning of the skin and the washing of calcium salts from the organs (the bones of such a corpse can be cut with a knife). This is peat doubling.

If the corpse is in conditions of low concentration of oxygen and high humidity then its soft parts turn to roughly-granular, tiny weight with a smell of rancid cheese or oil. This is the formation of the adipose.

Alteration

Alteration – tissue damage, and hence the cells and extracellular structures, which can be manifested in the form of dystrophy, atrophy, necrosis. These three concepts represent the oldest forms of cell damage, the stroma. Any alteration starts with damage to cells. At the cellular level, the alteration is a variety of ultrastructural changes that can be seen only in the microscope.

In general, the cell is an elementary living system with the ability to exchange with the environment and perform strictly specific functions. Specificity to cells is given by organelles. Organelles have specific morphological features that are aimed at performing the same strictly specific functions.

Regularity: all cell organelles are in causal relationships with each other and the cell is alive only if these relationships are performed normally, without failures. Otherwise, the cell is not able to perform its functions or may even die.

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