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


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

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 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 Brainerd, E. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Brainerd, E. L.

Journal of Experimental Biology, Vol 201, Issue 20 2891-2901, Copyright © 1998 by Company of Biologists

JOURNAL ARTICLES

Mechanics of lung ventilation in a larval salamander Ambystoma tigrinum

EL Brainerd
Department of Biology and Program in Organismic and Evolutionary Biology, Morrill South, University of Massachusetts, Amherst, MA 01003-5810, USA. brainerd@bio.umass.edu

The larval stage of the tiger salamander Ambystoma tigrinum is entirely aquatic, but the larvae rely on their lungs for a large proportion of their oxygen uptake. X-ray video and pressure measurements from the buccal and body cavities demonstrate that the larvae inspire using a two-stroke buccal pump and exhale actively by contracting the hypaxial musculature to increase body pressure. Larvae begin a breath by expanding the buccal cavity to draw in air through the mouth, while simultaneously exhaling air from the lungs to mix with the fresh air in the buccal cavity. The mouth then closes, and the buccal cavity compresses to pump a portion of the mixture into the lungs. The remaining air in the buccal cavity is then released as bubbles from the mouth and gill slits. Ventilatory volumes estimated from X-ray video records indicate that approximately 80 % of the air pumped into the lungs is fresh air and 20 % is previously expired air. Exhalation in larval tiger salamanders is active, powered by contraction of all four layers of lateral hypaxial musculature. Electromyography indicates that the transverse abdominis (TA) muscle is active for the longest duration and shows the highest-amplitude activity, but the external oblique superficialis, the external oblique profundus and the internal oblique also show consistent, low-level activity. The finding that the TA muscle is active during exhalation in larval tiger salamanders contributes to a growing body of evidence that the use of the TA for exhalation is a primitive character for tetrapods.


This article has been cited by other articles:


Home page
 Integr. Comp. Biol.Home page
E. L. Brainerd and R. S. Simons
Morphology and Function of Lateral Hypaxial Musculature in Salamanders
Integr. Comp. Biol., February 1, 2000; 40(1): 77 - 86.
[Abstract] [Full Text] [PDF]


© The Company of Biologists Ltd 1998