Animal anatomy, histology, pathological anatomy

Topic: Tuberculous nodule - 2 hours.


Topic Objectives: Teachstudents on macroscopic and microscopic manifestations of tuberculosis nodule. Visual equipment and instruments: Organ, microtome, block window box, eosin. Alcohol, xylene, paraffin, microscopy, histological specimen No. 76 and museum preparations Purpose of the lesson: Study of microscopic and macroscopic appearance. 1.Working pieces of pathological material will be cut from the kidneys and skeletal muscles. 2. The particles are washed and dehydrated in an alcohol battery. 3. Paraffin blocks are made. 4. Paint normal cuts. 5. Sections are stained with hematoxylin and eosin dyes. 6. Macroscopic changes are studied using museum preparations.

Course description: This is a chronic infectious disease of animals caused by mycobacteria and characterized by a special inflammation that forms nodules. Under natural conditions, the disease is transmitted through the respiratory tract and digestive tract. The disease occurs in all species of animals and birds. Disease-specific nodules form in parenchymal organs, mucous membranes and serum. In mammals, the primary complex is located in the lungs. Forms several nodules under the pleura. Damage occurs in one or more parts of the lungs.

At the center of the knot is a streamlined, cottage cheese-shaped fabric. In the lymph nodes, caseous foci of various shapes are formed, which appear in the cerebral cortex. In cattle and pigs, it is characterized by the formation of tumors and nodules in the lymph nodes. Primary intestinal lesions are rare. The process is characterized by the formation of nodules in the lymph nodes of the colon.
The increase in the incidence of tuberculosis is also caused by the reaction of the vessels around the source of tuberculosis and the outflow of serum exudate. The spread of tuberculosis also leads to impaired immune function, decreased resistance, malnutrition and deteriorating living conditions.
Tuberculosis bacteria multiply and attach to the fluid leaking from them, forming foci of tuberculosis in the tissues of the bird or spreading to other organs through the lymph and blood vessels, causing foci of tuberculosis, forming milliards. Large tuberculosis is characterized by the formation of large arrowhead or yellow nodules. Necrotic tissue in the center of the nodule can be transferred to the embryo in cows in 0.3 cases. Birds can pass through eggs.
The microscopic nodules are firm, round, and yellowish-white in the center. On palpation, a toxic formation is felt.
There are clinical and anatomical primary and secondary tuberculosis.
Primary changes begin where mycobacteria penetrate. When mycobacteria enter the respiratory tract, the primary lesions begin in the lungs and lymph nodes. Mycobacteria spread through the blood and lymph, causing characteristic changes in organs that allow them to multiply.
(In mammals - in the lungs, in birds - in the liver). When the lesion is in the organ and surrounding lymph nodes, it is called a complete primary complex. Only in the lymph nodes it is called an incomplete primary complex.
When primary complexes are found in more than one system, they are called complex primary complexes. (eg breathing and digestion). Most often found in the small and large intestines. In the biliary tract, tubercles also form in the intestinal mucosa. Small tubercles form in the lung parenchyma and under the pleura.
In the case of special osteomyelitis in the bones, it passes without coming out. Many tubercles form in the bone marrow. Only large tubercles form a caseous mass.
In ducks and geese, the main changes occur in the lungs.
The main pathological sign of tuberculosis is a nodule. (tubercle, infectious granuloma), very typical in structure. Changes in tuberculosis granulomas are productive inflammations, some of which may be exudative.
Tuberculosis often affects the lungs, lymph nodes, serous membranes, liver and mammary glands.
Pulmonary tuberculosis occurs in the form of primary, billionth and large tubercles (nadose form), acinosis form and diffuse form. In the chronic form of tuberculosis, cavities form in the lung tissue.
Macroscopic view.
Caseosis begins with hyperemia of the lung tissue, followed by filling of the small bronchi, bronchioles and alveoli with serum exudate emanating from the blood vessels. The resulting exudate quickly coagulates and turns into kerosene. Later, the connective tissue between the walls of the alveoli, bronchi, bronchioles and individual segments undergo necrosis, which leads to the formation of a brownish-yellow mass in many areas of the lung.
Microscopic view.
At the site of the inflammatory reaction, the structure of the connective tissue fibers and walls of the large bronchi is preserved, and a caseous substance is released. The surviving connective tissue then grows and forms a crust of larger nodules. If you look into a small mirror, you can see eosin-stained reddish lung tissue. In a large mirror, casein appears granular. Around the caseous (degraded) substance are epithelioid cells, fibroblasts and smaller cells, as well as a large number of lymphoid cells outside the center. Epithelioid cells and fibroblasts are mixed with caseous material. Lime in caseous matter