Morphological features and morphometric parameters of the lungs of sexually mature horses (Equus Ferus Caballus L., 1758)

The lungs, which form part of the respiratory apparatus, provide gas exchange between the environment and the tissues of the human and animal body. Therefore, lung diseases are one of the most pressing issues for modern humane and veterinary medicine. This problem is caused by the progressive growth of diseases in mammals such as bronchial asthma, bronchitis, bronchopneumonia, pneumonia, coronavirus infections, etc. Therefore, to effectively solve this issue in terms of prevention, effective treatment, and prompt differential diagnosis of respiratory diseases, an essential area in morphology is the study of the respiratory apparatus, namely the lungs, in clinically healthy animals, to develop marker test criteria that will serve as indicators of the norm in the differential diagnosis of these diseases. The purpose of this study was to investigate the macro- and microscopic structure of the lungs, conduct a morphometric assessment of their morphological structures in domestic sexually mature horses (class Mammals, species – domestic horse (Equus ferus caballus L., 1758). The object of this study was the lungs of clinically healthy sexually mature horses (n=5). Fresh lungs of the animals under study were subjected to anatomical preparation. For histological studies, generally accepted methods of fixing pieces of material and making histological sections were used, which were then stained with haematoxylin and eosin and according to Van Gieson’s method. The basis of the lungs in horses are pyramidal or cone-shaped lobules. Part of the structure of the lobes are acini covered with a thin layer of connective tissue. The microscopic structure of acini is formed by alveolar ducts, alveolar sacs, and alveoli. According to the results of research, the alveolar tree in horses is shortened and wide and has a bubble shape. The results of morphometric studies showed that the average volume of pulmonary alveoli in clinically healthy horses is 699.80±106.42 thous. μm3. The respiratory part of the lungs in horses occupies 54.8±7.4% of the total area of the lung parenchyma, the connective tissue base – 45.2±7.4%. Such studies of morphological features and morphometric parameters of equine lungs are of practical importance in veterinary medicine since they are markers and criteria for pathomorphological diagnosis of diseases associated with the respiratory system