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The ultrastructure of the pharynx of some developing larvae of ascaris suum

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Summary

Electronmicroscope observations of the pharynx of the 2nd stage infective larva reveal that it is devoid of musculature and is therefore incapable of any pumping activity. By the 8th day when the larva is situated in the host lung however, the radial muscles are well developed and the organ appears to be fully functional.

Active secretory glands are present in the pharynx of both the infective and lung stage larvae but those of the latter contain a greater variety of secretory bodies. It is suggested that the pharyngeal glands of the infective larva secrete lytic substances to facilitate host tissue penetration whilst the secretory products of the lung stage larva are concerned with a more diverse range of functions including feeding.

No valve like structure was discernable at the pharyngeo-intestinal junction of the larvae recovered from the host lungs 8 days after infection. It is suggested that the cells of the pharyngeo-intestinal junction, function as a shock absorber between the highly mobile pharynx and the relatively static intestine.

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Authors and Affiliations

  1. Department of Zoology, University College, Cardiff, Great Britain

    D. Conwil Jenkins

  2. The Research Laboratories May and Baker Ltd., RM10 7XS, Dagenham, Essex, Great Britain

    D. Conwil Jenkins

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  1. D. Conwil Jenkins
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Jenkins, D.C. The ultrastructure of the pharynx of some developing larvae of ascaris suum . Z. F. Parasitenkunde 37, 255–266 (1971). https://doi.org/10.1007/BF00259332

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  • DOI: https://doi.org/10.1007/BF00259332

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