Study of cellular and tissue changes at the ultrastructural and histological level as part of the systemic (patho)physiological response of the organism in various experimental conditions or during ontogenetic development. Some of the topics of interest: plasticity of adipose tissue in a model of systemic hypo- and hyperthyroidism; structural characteristics of endocrine and exocrine glands in conditions of impaired homeostasis; assessment of toxic and/or immunomodulatory effects of the heavy metal cadmium through histopathological changes in various organs within the framework of immunotoxicological studies; histological organization of certain organs of tailed amphibians at different stages of development.