title: Development of the cardiorespiratory system in dogs from days 16 to 46 of pregnancy.
abstract: Dogs have been studied for several reasons, such as the genetic improvement, their use as experimental models, in zoonotic research, cell therapy and as a model for human diseases. However, many features relating to the embryonic development of dogs remain unknown because of the absence of embryological studies. Considering the importance of the cardiorespiratory system in the development of embryos, the aim of this study was to investigate the development of the main cardiorespiratory organs of dog embryos and foetuses with estimated gestational ages from 16 to 46 days using macro- and microscopic descriptions. On day 16 of development, the neural tube and crest were formed, the anterior and posterior neuropore closure had begun and the somites had developed. Between days 22 and 27 of gestation, the lung buds and the initial formation of the primary bronchi and heart chambers were observed. The heart chambers exhibited the endo-, myo- and epicardial layers but did not have obvious differences in thickness among each other. Between days 41 and 46 of gestation, the nasal conchae and septa and trachea were formed, which exhibited characteristic epithelia. The lung formation and lobation were complete. The heart and major vessels exhibited mature histological architecture when their anatomical development was complete. The results of this study contribute to a more accurate definition of the embryonic and foetal developmental stages in dogs.
authors: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors: A A
authors: AA
authors: Martins
authors: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. phelipe.favaron@yahoo.com.br.
authors: P O
authors: PO
authors: Favaron
authors: Department of Animal Science, Faculty of Animal Sciences and Food Engineering, University of Sao Paulo, Pirassununga, São Paulo, Brazil.
authors: L
authors: L
authors: de Jesus Oliveira
authors: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors: B T
authors: BT
authors: Schäfer
authors: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors: F D
authors: FD
authors: Oliveira
authors: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors: M A
authors: MA
authors: Miglino
mesh_terms: D000818:Animals; D004285:Dogs / Q000196:embryology* / Q000502:physiology; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005865:Gestational Age; D006321:Heart / Q000196:embryology*; D008168:Lung / Q000196:embryology*; D011247:Pregnancy