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Blood Vessels and Related Structures in the Gill Bars of Glossobalanus minutus (Enteropneusta)
Author(s) -
Pardos Fernando,
Benito Jesús
Publication year - 1988
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1988.tb00905.x
Subject(s) - biology , anatomy , ultrastructure , circulatory system , lumen (anatomy) , blood vessel , basement membrane , microbiology and biotechnology , endocrinology
The branchial circulatory system of Glossobalanus minutus (Enteropneusta) is investigated by means of transmission electron microscopy. Primary gill bars, or septa, have a single blood vessel longitudinally located along the outer edge of the bar. Secondary gill bars, or tongue bars, show a vessel in their inner, pharyngeal edge. The walls of both vessels are made up of the basement membranes of surrounding epithelia, lacking an endothelium. No definite limits between the vessel lumen and the skeletal rods inside the bars can be seen. Furthermore, the blood seems to penetrate into the rods of both primary and secondary gill bars. In the secondary bars such a phenomenon gives rise to the so‐called ‘lateral vessels’ reported in the light microscopical literature. The significance of these observations is discussed, with special reference to the gill circulatory system of amphioxus, which seems to be strongly similar from a morphological and ultrastructural point of view.