Talk:2009 Lecture 10

Background Reading

• Development of the pulmonary veins; with reference to the embryology of anomalies of pulmonary venous return. NEILL CA. Pediatrics. 1956 Dec;18(6):880-7. No abstract available. PMID: 13378917 | Pediatrics

• Classic imaging signs of congenital cardiovascular abnormalities.

Ferguson EC, Krishnamurthy R, Oldham SA. Radiographics. 2007 Sep-Oct;27(5):1323-34. Review. PMID: 17848694 http://radiographics.rsna.org/content/27/5/1323.long

pulmonary vein origin

• Development and structures of the venous pole of the heart. Anderson RH, Brown NA, Moorman AF. Dev Dyn. 2006 Jan;235(1):2-9. Review. PMID: 16193508

"The origin of the pulmonary vein remains controversial. Although all now agree that the vein itself canalizes from a mid-pharyngeal strand at approximately 6 weeks of development in the human (Blom et al., [2001]) and opens into the atrium between the ridges marking the site of the dorsal mesocardial connection, arguments continue as to whether or not this part of the developing atrium should be considered part of the sinus venosus (Hochstetter, [1908]; Auër, [1941]). Some argue that the area should be considered as part of the sinus venosus because the tissues surrounding the dorsal mesocardium, along with those surrounding the systemic venous tributaries, stain positively for an antibody to human natural killer cells (deRuiter et al., [1995]). The staining properties of the antibody to the human killer cells, however, are also cited as evidence that cells are derived from the neural crest (Verberne et al., [1998]) or that they are primordia of conducting tissues (Blom et al., [1999]). In reality, these antibodies stain migrating populations of cells (Tucker et al., [1984]; Kuratani and Kirby, [1991]), including those derived from the neural crest, and those entering the heart to form the mediastinal myocardium. The neural crest, furthermore, also produces the parasympathetic neural input to the heart, which also enters the heart primarily through the venous pole. Positive staining of antibodies to human natural killer cells, therefore, does not prove that the myocardium surrounding the pulmonary vein is derived from the sinus venosus. In fact, our own findings using molecular markers show that the myocardium surrounding the pulmonary venous orifice, from the time of its first appearance within the developing atrium, stains positively for connexin40. Thus, it is readily distinguished from the primary myocardium surrounding the orifices of the systemic venous tributaries. This evidence, coupled with the timing of appearance of the pulmonary venous channel, at approximately Carnegie stage 12 in the human and during the ninth day in the mouse, shows that the pulmonary vein is a new structure. It does not take its origin from the sinus venosus, the latter never existing as a discrete compartment of the developing mammalian heart."

"The pulmonary vein, therefore, has never been part of the so-called sinus venosus, nor does it take its origin from the systemic venous tributaries."

human heart

• pulmonary vein opens initially as a solitary orifice adjacent to the atrioventricular junctions
• subsequent to the division of the primary atrial chamber into its right and left parts by growth of the primary atrial septum, the pulmonary veins remodel so as to gain separate entrances at the four corners of the roof of the body of the left atrium
• as the right pulmonary veins gain their entrance to the atrial roof infolding of the wall between their mouths and the orifices of the systemic venous sinus entering the right atrium.
• infolding produces the septum secundum (superior interatrial fold).