Circulatory system. General and specific characteristics of the heart: morphology, structure and interspecific differences. Arterial, venous and lymphatic vessels: general characteristics, structure and differences. The main arterial and venous vessels of the body. Lymph nodes, thymus and spleen. Respiratory system. General, specific and structural features of various organs: the nasal cavities, larynx, trachea, bronchial tree and lungs.