Animal anatomy, histology, pathological anatomy

Topic: Horny dystrophy - 2 hours
Objectives of the topic: To teach students the macroscopic and microscopic manifestations of dystrophy using the example of skin. Visual equipment and instruments: Organ, microtome, block window box, hematoxilin, eosin. Alcohol, xylene, paraffin, microscopy, histological specimen No. 35 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. Corneal dystrophy is excessive formation of horny substance in the cell (hyperkeratosis, isthiosis). Normal skin is velvety, without acne and even in color. In pathological conditions, excessive frostbite and deterioration in quality (parakeratosis) are possible. For example, in mucous membranes (leukoplakia), epithelial tumors (for example, squamous cell carcinoma, the formation of “cancer pearls”), pathological branching can occur. An example of hyperkeratosis is protective blisters that form as a result of prolonged itching. Under the microscope, we see that the epidermis is covered with a large amount of horny material, and the Malpighian layer thickens as a result of cell hyperplasia. Parakeratosis - (Greek para - next, keratis - horny substance) - loss of keratohyalin produced by epidermal cells leads to the formation of horns. This thickens the stratum corneum and forms thick patches on the skin. Under a microscope, rod cells with rod-shaped nuclei are detected. Parakeratosis is observed in dermatitis. Leukoplakia is an abnormal branching of the mucous membranes as a result of exposure, as well as inflammation and vitamin A deficiency. For example, in pigs, the mucous membrane branches foreskin as a result of chronic contact with urine. A nodule of round white-gray matte epithelium. Occasionally, such cases can be found in the urethra, bladder, and large abdomen of cattle. Vitamin A branches into the epithelium of the mouth, throat and esophagus.

Macroscopic view. Dystrophy manifests itself in the form of nodular flat forms on the skin. The surface of the nodules is uneven and brown. On the cut surface we see semi-dry branching material.

Under a microscope, the Histopreparation shows keratin in the cytoplasm of branched epithelial cells. The carotene in eosin appears bright red. Branched epithelial cells form layers and look like cells. In the center is bright red spotted carotene.