Zoological terms in the human histological nomenclature Terminologia Histologica. What we think, what we know, and what we think we know

Abstract

Terminology in morphological and zoological sciences is enormously important. Proper denomination of individual structures of the animal / human body from the microscopic point of view has an irreplaceable role in unambiguous understanding and communication among scientists regardless of their field of expertise. The year 2008 can be considered a crucial year in the developing of internationally accepted histological terminology, because it was the year when the first internationally renowned human histology nomenclature Terminologia Histologica was published. The current version of the Terminologia Histologica contains also the description of many microscopic organs and structures whose presence in different animal species is widely accepted, however their presence in humans is disputable. Typical examples are the haemal lymph nodes and haemal nodes, mentioned in the chapter Lymphoid organs which are secondary lymphoid organs found in many different mammalian species, but also in some birds. They are capable of performing haematopoietic and immunological functions but in the absence of lymphatic system pathology, no structures resembling haemal nodes / haemal lymph nodes have been detected in humans. Neurohaemal organs are mentioned within the chapter Endocrine system. Neurohaemal organs are known by different names, depending on the animal species studied, e.g. corpora allata or abdominal perisympathetic organs. To this date, these structures have been described in many different invertebrate species, but neurohaemal organs are also found in some lower vertebrates, in which the neurohaemal organ is referred to as “urophysis”. According to our opinion, structures called neurohaemal organs in invertebrates are counterparts to circumventricular organs found in vertebrates, but cannot be named as such. Another somewhat controversial term mentioned in human histological nomenclature is the vomeronasal organ mentioned in the chapter Respiratory system. It is a specialized organ, which forms an integral supportive part of the olfaction of many mammalian species and reptiles. It is believed that the main function of vomeronasal organ is to regulate various behavioral aspects of intraspecies interaction by facilitating the detection of pheromones. The function and even existence of the vomeronasal organ in humans is a source of significant dispute among researchers. Some of them stated that vomeronasal organ disappears during fetal development, with except the vomeronasal duct. On the other hand, there are also authors who concluded that the vomeronasal organ is definitely present in adult humans. Similarly disputable question is the presence of multinucleated plasmodia in human body. This opinion article aims to open a wide scientific discussion concerning the importance and aptness of the inclusion of these terms in the human histological nomenclature despite they are probably exclusively zoological.