spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online September 16, 2005
Journal of Experimental Biology 208, 3637-3643 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01789
This Article
Right arrow Summary Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary Material
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 Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Thornton, S. J.
Right arrow Articles by Pelc, N. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Thornton, S. J.
Right arrow Articles by Pelc, N. J.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Stroke volume and cardiac output in juvenile elephant seals during forced dives

Sheila J. Thornton1,*, Peter W. Hochachka1,{dagger}, Daniel E. Crocker2, Daniel P. Costa3, Burney J. LeBoeuf3, Daniel M. Spielman4 and Norbert J. Pelc4

1 Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, British Columbia V6T 1Z4, Canada
2 Department of Biology, Sonoma State University, 1801 East Cotati Avenue, Rohnert Park, CA 94928-3609, USA
3 Department of Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
4 Department of Radiology, Stanford University, Lucas Center for MR Imaging and Spectroscopy, Stanford, CA 94305, USA



View larger version (46K):

[in a new window]
  		Fig. 1. MR axial images of a northern elephant seal pup during cardiac phase-contrast data acquisition. Localizer image (A) shows the location selected for flow analysis and the position of the aorta. In phase-contrast images A and B, image intensity is proportional to the velocity component of the blood along the superior/inferior direction. Image B was obtained during systole (frame 4 of 36), and image C is near the end of diastole (frame 27 of 36). Black indicates superior (cranial) flow and white represents flow in the inferior (caudal) direction.

 


View larger version (14K):

[in a new window]
  		Fig. 2. Diving stroke volume (VS) correlates with the degree of bradycardia expressed during the dive [ratio of mean diving heart rate (fH) to mean pre-dive fH (P=0.01, r2=0.98; y=-47.83x+150.56)]. Although the degree of bradycardia is correlated with VS, the absolute fH during the dive is not, suggesting that it is the degree of cardiac response to diving that is driving the increase in VS rather than the absolute rate of contraction.

 


View larger version (28K):

[in a new window]
  		Fig. 3. Stroke volume data from an individual northern elephant seal during the pre-dive, dive and post-dive (PD) periods. Blood flow (ml) over a cardiac cycle during the dive exhibited a distinct peak in the first quarter of the cardiac cycle, then decreased momentarily before leveling off. In the second half of the cardiac cycle (frames 17-32), flow did not fall to zero at any point [mean flow (± S.E.M.) per frame = 2.23±0.08 ml].

 

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?



© The Company of Biologists Ltd 2005