Cardiovascular Function in the Lower Vertebrates

Johansen, Kjell; Burggren, Warren W.

doi:10.1016/b978-0-12-119401-7.50009-8

Cited by 40 publications

(43 citation statements)

References 94 publications

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“…Discussion Systemic blood pressure of Python molurus is similar to mammals and considerably higher than in most other reptiles with the exception of varanid lizards (e.g. Johansen and Burggren, 1980;Burggren and Johansen, 1982;Shelton, 1993;Hicks, 1998;Burggren et al, 1998). Pulmonary arterial pressure is, on the other hand, lower than in any other reptiles, including varanid lizards.…”

Section: Arterial and Intraventricular Pressures In Anaesthetised Snakesmentioning

confidence: 94%

Ventricular haemodynamics inPython molurus: separation of pulmonary and systemic pressures

Wang

Altimiras

Klein

et al. 2003

Journal of Experimental Biology

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SUMMARYVascular pressure separation by virtue of a two-chambered ventricle evolved independently in mammals and birds from a reptilian ancestor with a single ventricle, and allowed for high systemic perfusion pressure while protecting the lungs from oedema. Within non-crocodilian reptiles, ventricular pressure separation has only been observed in varanid lizards and has been regarded as a unique adaptation to an active predatory life style and high metabolic rate. The systemic and pulmonary sides of the ventricle in Python molurusare well separated by the muscular ridge, and a previous study using in situ perfusion of the heart revealed a remarkable flow separation and showed that the systemic side can sustain higher output pressures than the pulmonary side. Here we extend these observations by showing that systemic blood pressure Psys exceeded pulmonary pressure Ppul almost seven times (75.7±4.2 versus11.6±1.1 cm H2O). The large pressure difference between the systemic and pulmonary circulation persisted when Psys was altered by infusion of sodium nitroprusside or phenylephrine. Intraventricular pressures, measured in anaesthetised snakes, showed an overlap in the pressure profile between the pulmonary side of the ventricle (cavum pulmonale) and the pulmonary artery, while the higher pressure in the systemic side of the ventricle (cavum arteriosum) overlapped with the pressure in the right aortic arch. This verifies that the pressure differences originate within the ventricle, indicating that the large muscular ridge separates the ventricle during cardiac contraction.

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Section: Arterial and Intraventricular Pressures In Anaesthetised Snakesmentioning

confidence: 94%

Ventricular haemodynamics inPython molurus: separation of pulmonary and systemic pressures

Wang

Altimiras

Klein

et al. 2003

Journal of Experimental Biology

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“…The bony fish bulbus arteriosus might thus be homologous to the shark conus arteriosus and amphibian/mammalian bulbus cordis. velopment as a separate cardiac compartment as well as the development of the sinoatrial valves that physically separate sinus venosus from atrium during contraction have allowed the development of the atrium as the principal driving force for ventricular filling (142,143). This role has become less important in mammalian hearts where collection of blood is the principle function of the atria.…”

Section: Fishesmentioning

confidence: 99%

“…A typical amphibian heart has two atria, a single ventricle, and a bulbus cordis (the amphibian equivalent of the fish conus arteriosus) (127,143,342). The sinus venosus drains exclusively to the right atrium.…”

Section: Amphibiansmentioning

confidence: 99%

Cardiac Chamber Formation: Development, Genes, and Evolution

Moorman

Christoffels

2003

Physiological Reviews

650

526

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Moorman, Antoon F. M., and Vincent M. Christoffels. Cardiac Chamber Formation: Development, Genes, and Evolution. Physiol Rev 83: 1223-1267, 2003; 10.1152/physrev.00006.2003.—Concepts of cardiac development have greatly influenced the description of the formation of the four-chambered vertebrate heart. Traditionally, the embryonic tubular heart is considered to be a composite of serially arranged segments representing adult cardiac compartments. Conversion of such a serial arrangement into the parallel arrangement of the mammalian heart is difficult to understand. Logical integration of the development of the cardiac conduction system into the serial concept has remained puzzling as well. Therefore, the current description needed reconsideration, and we decided to evaluate the essentialities of cardiac design, its evolutionary and embryonic development, and the molecular pathways recruited to make the four-chambered mammalian heart. The three principal notions taken into consideration are as follows. 1) Both the ancestor chordate heart and the embryonic tubular heart of higher vertebrates consist of poorly developed and poorly coupled “pacemaker-like” cardiac muscle cells with the highest pacemaker activity at the venous pole, causing unidirectional peristaltic contraction waves. 2) From this heart tube, ventricular chambers differentiate ventrally and atrial chambers dorsally. The developing chambers display high proliferative activity and consist of structurally well-developed and well-coupled muscle cells with low pacemaker activity, which permits fast conduction of the impulse and efficacious contraction. The forming chambers remain flanked by slowly proliferating pacemaker-like myocardium that is temporally prevented from differentiating into chamber myocardium. 3) The trabecular myocardium proliferates slowly, consists of structurally poorly developed, but well-coupled, cells and contributes to the ventricular conduction system. The atrial and ventricular chambers of the formed heart are activated and interconnected by derivatives of embryonic myocardium. The topographical arrangement of the distinct cardiac muscle cells in the forming heart explains the embryonic electrocardiogram (ECG), does not require the invention of nodes, and allows a logical transition from a peristaltic tubular heart to a synchronously contracting four-chambered heart. This view on the development of cardiac design unfolds fascinating possibilities for future research.

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“…The ventricle of non-crocodilian reptiles is not fully divided, but is partitioned into two subcompartments, the cavum dorsale and the cavum pulmonale (Johansen & Burggren, 1980;van Mierop & Kutsche, 1985;Hicks, 1998). The pulmonary artery emerges from the cavum pulmonale (CP), which is separated from the larger cavum dorsale by a muscular ridge that runs from the apex to the base of the ventricle (van Mierop & Kutsche, 1985).…”

Section: Anatomy Of the Heart And The Basis For Vagal Control Of Cardmentioning

confidence: 99%

“…In addition to the wash-out shunt, blood can be shunted between the CP and the cavum dorsale during Ventricular systole if the muscular ridge incompletely segregates these chambers. The magnitude of this 'pressure shunt' depends on the size of the opening between the chambers and the pressure gradient across the opening, both of which are partially determined by cardiac contractility and differences in outflow resistance between the pulmonary and systemic circulation (Johansen & Burggren, 1980;Heisler & Glass, 1985;Hicks, 1998).…”

Section: Anatomy Of the Heart And The Basis For Vagal Control Of Cardmentioning

confidence: 99%