Biol. Bull. Sign up for etocs!
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by McCurley, R. S.
Right arrow Articles by Kier, W. M.
Right arrow Search for Related Content
PubMed
Right arrow Articles by McCurley, R. S.
Right arrow Articles by Kier, W. M.

The Biological Bulletin, Vol 188, Issue 2 197-209, Copyright © 1995 by Marine Biological Laboratory

PHYSIOLOGY

The Functional Morphology of Starfish Tube Feet: The Role of a Crossed-Fiber Helical Array in Movement

R. S. McCurley and W. M. Kier
Department of Biology, CB#3280 Coker Hall, University of North Carolina, Chapel Hill, North Carolina 27599-3280

The morphology and mechanics of the tube feet, ampullae, and lateral and radial canals of the water vascular systems of Luidia clathrata and Astropecten articulatus (Echinodermata, Asteroidea) were analyzed. Histological methods, based on embedding in both paraffin and glycol methacrylate, were used to document the arrangement of muscle and connective tissue. The tube foot wall includes longitudinal muscles and connective tissue fibers, the latter arranged in a crossed-fiber helical array, with a fiber angle of about 67{deg} in elongated tube feet. No evidence was found for the circular rings of connective tissue reported in earlier studies; the appearance of rings is probably an artifact of folding. The ampullae are bilobed and include circumferentially arranged muscle fibers and connective tissue fibers aligned 90{deg} to the muscle. The lateral canals are short and equipped with oneway flap valves similar to those described for other echinoderms. The radial canal is thin-walled, nonmuscular, and enclosed in the connective tissue and ossicles of the ambulacrum. Frame-by-frame video analysis of both intact animals and animals with "windows" cut in the arm wall was used to document the movements of the tube feet and ampullae. No evidence was found for the previously suggested role of the radial canal in protracting the tube feet. The ampullae protract the tube feet and antagonize the tube foot musculature. The fiber angle of the connective tissue allows protraction and prevents dilation of the tube feet, and limits elongation of the ampullae.


This article has been cited by other articles:


Home page
 J. Exp. Biol.Home page
R. E. Shadwick
FOUNDATIONS OF ANIMAL HYDRAULICS: GEODESIC FIBRES CONTROL THE SHAPE OF SOFT BODIED ANIMALS
J. Exp. Biol., February 1, 2008; 211(3): 289 - 291.
[Full Text] [PDF]

Home page
 Ann. N. Y. Acad. Sci.Home page
D. A. KELLY
Penises as Variable-Volume Hydrostatic Skeletons
Ann. N.Y. Acad. Sci., April 1, 2007; 1101(1): 453 - 463.
[Abstract] [Full Text] [PDF]

Home page
 J. Exp. Biol.Home page
R. Santos, D. Haesaerts, M. Jangoux, and P. Flammang
The tube feet of sea urchins and sea stars contain functionally different mutable collagenous tissues
J. Exp. Biol., June 15, 2005; 208(12): 2277 - 2288.
[Abstract] [Full Text] [PDF]

Home page
 Integr. Comp. Biol.Home page
M. S. Vickery and J. B. McClintock
Comparative Morphology of Tube Feet Among the Asteroidea: Phylogenetic Implications
Integr. Comp. Biol., June 1, 2000; 40(3): 355 - 364.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1995 by the Marine Biological Laboratory.