Although the heart atria have a lesser functional importance than the ventricles, atria play an important role in the pathophysiology of heart failure and supraventricular arrhythmias, particularly atrial fibrillation. In addition, knowledge of atrial morphology recently became more relevant as cardiac electrophysiology and interventional procedures in the atria gained an increasingly significant role in the clinical management of patients with heart disease. The atrial chambers are thin-walled, and several vessels enter at the level of the atria. The left and right atrium have different structures and shape. In general, both atrial chambers have the venous part, the appendage, and the vestibule; different aspects of each part allow us to distinguish morphologically between the left and right atrium. The human atrial conduction system consists of the sinus node and the atrioventricular node with no histologically specialized conduction pathways in the atrial chamber and an interatrial connection. The data show that the propagation of the impulse depends mainly on the myocardial architecture in the atria and the orientation of the myocytes plays a significant role in conduction. To complete the picture, it is also important to know how the atria develop and what is the embryonic origin of its different structures, as this may play a role in the development of some pathological conditions such as atrial fibrillation or certain types of congenital heart defects. Functional impairment of the atria can in some situations severely compromise heart pumping function, and conversely, can support it if other areas are damaged, balancing the blood flow to the body for some time. Key words Morphology of atrial chambers, Pectinate muscles, Atrial function.

• MeSH
• lidé MeSH
• převodní systém srdeční * fyziologie   MeSH
• srdce - funkce síní * fyziologie   MeSH
• srdeční síně * embryologie   anatomie a histologie   růst a vývoj   MeSH
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• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
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A well-developed heart is essential for embryonic survival. There are constant interactions between cardiac tissue motion and blood flow, which determine the heart shape itself. Hemodynamic forces are a powerful stimulus for cardiac growth and differentiation. Therefore, it is particularly interesting to investigate how the blood flows through the heart and how hemodynamics is linked to a particular species and its development, including human. The appropriate patterns and magnitude of hemodynamic stresses are necessary for the proper formation of cardiac structures, and hemodynamic perturbations have been found to cause malformations via identifiable mechanobiological molecular pathways. There are significant differences in cardiac hemodynamics among vertebrate species, which go hand in hand with the presence of specific anatomical structures. However, strong similarities during development suggest a common pattern for cardiac hemodynamics in human adults. In the human fetal heart, hemodynamic abnormalities during gestation are known to progress to congenital heart malformations by birth. In this chapter, we discuss the current state of the knowledge of the prenatal cardiac hemodynamics, as discovered through small and large animal models, as well as from clinical investigations, with parallels gathered from the poikilotherm vertebrates that emulate some hemodynamically significant human congenital heart diseases.

• Klíčová slova
• Axolotl, Chick embryo, DORV, Developing myocardium, ET1, Embryogenesis, Endothelin 1, Fetal heart, Guinea pig, HLHS, Hemodynamics, Hyperplasia, Hypertrophy, Hypoplastic left heart syndrome, KLF2, Krüppel-like factor 2, Lamb, Mouse, NOS3, Nitric oxide synthase 3, Pressure overload, Rat, Reptile, VSD, Volume overload, Zebrafish,
• MeSH
• hemodynamika * fyziologie   MeSH
• lidé MeSH
• srdce * růst a vývoj   fyziologie   MeSH
• vrozené srdeční vady patofyziologie   MeSH
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• časopisecké články MeSH
• přehledy MeSH

The group Anguimorpha represents one of the most unified squamate clades in terms of body plan, ecomorphology, ecophysiology and evolution. On the other hand, the anguimorphs vary between different habitats and ecological niches. Therefore, we focused on the group Anguimorpha to test a possible correlation between heart morphology and ecological niche with respect to phylogenetic position in Squamata with Sphenodon, Salvator, and Pogona as the outgroups. The chosen lepidosaurian species were investigated by microCT. Generally, all lepidosaurs had two well-developed atria with complete interatrial septum and one ventricle divided by ventricular septa to three different areas. The ventricles of all lepidosaurians had a compact layer and abundant trabeculae. The compact layer and trabeculae were developed in accordance with particular ecological niche of the species, the trabeculae in nocturnal animals with low metabolism, such as Sphenodon, Heloderma or Lanthanotus were more massive. On the other hand athletic animals, such as varanids or Salvator, had ventricle compartmentalization divided by three incomplete septa. A difference between varanids and Salvator was found in compact layer thickness: thicker in monitor lizards and possibly linked to their mammalian-like high blood pressure, and the level of ventricular septation. In summary: heart morphology varied among clades in connection with the ecological niche of particular species and it reflects the phylogenetic position in model clade Anguimorpha. In the absence of fossil evidence, this is the closest approach how to understand heart evolution and septation in clade with different cardiac compartmentalization levels.

• Klíčová slova
• Lanthanotus, Salvator, Sphenodon, Varanus, evolutionary traits, septation, ventricle,
• Publikační typ
• časopisecké články MeSH