Oesophageal pouch

The oesophageal pouches (also known as sugar glands)[1] are a pair of pouches connected to the oesophagus of all molluscs, and represent a synapomorphy of the phylum.[2]

Morphology

Usually forming a pair of lateral structures, oesophageal pouches take various forms, but usually account for a fair portion of the anterior volume of the creeping molluscs and scaphopods.[3][4][5][6][7] There is a single pouch ventral to the rear of the radula in some nudibranch sea slugs.[6] The pouches are lined with ciliated secretory cells.[8]

Function

The pouches contain digestive enzymes that break down starch and other polysaccharides,[1] and also extrude mucus.[6]

Occurrence

The features are considered ancestral to molluscs,[2] but have been secondarily lost in the Heterobranchia.[9] However, it is not certain that all oesophageal diverticulae are homologous.[10][11]

References

  1. 1 2 STONE AND MORTON. "THE DISTRIBUTION OF CELLULASES AND RELATED ENZYMES IN MOLLUSCA" (PDF). J. Mollus. Stud. (1958) 33 (3): 127-141.
  2. 1 2 Sturm, Charles F; Pearce, Timothy A; Valdés, ÁNgel (July 2006). The mollusks: a guide to their study, collection, and preservation. ISBN 978-1-58112-930-4.
  3. ↑ Haszprunar, G. (1987). "Anatomy and affinities of cocculinid limpets (Mollusca, Archaeogastropoda)". Zoologica Scripta 16 (4): 305–324. doi:10.1111/j.1463-6409.1987.tb00077.x.
  4. ↑ Haszprunar, G. (1989). "The Anatomy of Melanodrymia aurantiaca Hickman, a Coiled Archaeogastropod from the East Pacific Hydrothermal Vents (Mollusca, Gastropoda)". Acta Zoologica 70 (3): 175–186. doi:10.1111/j.1463-6395.1989.tb01068.x.
  5. ↑ Ruthensteiner, B.; Schropel, V.; Haszprunar, G. (2010). "Anatomy and affinities of Micropilina minuta Warén, 1989 (Monoplacophora: Micropilinidae)". Journal of Molluscan Studies 76 (4): 323–332. doi:10.1093/mollus/eyq013.
  6. 1 2 3 Crampton, D. M. (2010). "Functional anatomy of the buccal apparatus of Onchidoris bilamellata (Mollusca: Opisthobranchia)". The Transactions of the Zoological Society of London 34: 45. doi:10.1111/j.1096-3642.1977.tb00372.x.
  7. ↑ Urgorri, V.; García-Álvarez, O.; Luque, . (2005). "Laevipilina Cachuchensis, A New Neopilinid (Mollusca: Tryblidia) from off North Spain". Journal Molluscan Studies 71: 59–66. doi:10.1093/mollus/eyi008.
  8. ↑ Morton, J. E. (2009). "The habits and feeding organs of Dentalium entalis". Journal of the Marine Biological Association of the United Kingdom 38 (02): 225. doi:10.1017/S0025315400006032.
  9. ↑ Ponder, W. F. (1991). "MARINE VALVATOIDEAN GASTROPODS—IMPLICATIONS FOR EARLY HETEROBRANCH PHYLOGENY". Journal of Molluscan Studies 57: 21. doi:10.1093/mollus/57.1.21.
  10. ↑ Lobo-Da-Cunha, A.; Oliveira, E.; Alves, Â.; Coelho, R.; Calado, G. (2010). "Light and electron microscopic study of the anterior oesophagus ofBulla striata(Mollusca, Opisthobranchia)". Acta Zoologica 91 (2): 125–138. doi:10.1111/j.1463-6395.2009.00392.x.
  11. ↑ Malacologia 37: 375–442. 1996. Missing or empty |title= (help)
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