QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Vitalis, T. Z. Articles by Milsom, W. K. Search for Related Content PubMed Articles by Vitalis, T. Z. Articles by Milsom, W. K. Social Bookmarking                         What's this?

Journal of Experimental Biology 125,157-171 (1986)
Published by Company of Biologists 1986

Mechanical Analysis of Spontaneous Breathing in the Semi-Aquatic Turtle, Pseudemys Scripta

Timothy Z. Vitalis ¹ and William K. Milsom ²

¹ Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T2A9, Canada: School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK.
² Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T2A9, Canada

The normal breathing pattern of Pseudemys scripta (Schoepff) consists of a continuous burst of breaths separated by a variable period of breath holding. Under normoxic conditions, tidal volume was 6.9 ml kg^-1 and the number of breaths was 1.9 min^-1. Increases in pulmonary ventilation upon stimulation by hypercapnia (3% CO₂) or hypoxia (4% O₂) are caused primarily by increases in the number of breaths per minute due to a shortening of the breath-hold period. Tidal volume and breath duration remain unchanged. The instantaneous breathing frequency (f' = 60/T_tot) of 35 ± 2min^-1 corresponds to continuous pump frequencies that minimize the rate of the mechanical work of breathing in anaesthetized turtles. This indicates that turtles breathe at a combination of tidal volume and f' that minimizes the power required to ventilate the lungs. To increase ventilation, the breath hold is shortened and more breaths are taken at this optimal combination. Bilateral vagotomy drastically alters the breathing pattern, producing an elevation in tidal volume, a slowing of breathing frequency, and a prolongation of breath duration while total ventilation remains unchanged. These data suggest that periodic breathing in this species may represent an adaptive strategy which is under vagal control and which serves to minimize the cost of breathing.

Key words: reptiles, pulmonary mechanics, breathing pattern regulation.

Accepted on April 18, 1986

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

This article has been cited by other articles:

				C. Reyes and W. K. Milsom Daily and seasonal rhythms in the respiratory sensitivity of red-eared sliders (Trachemys scripta elegans) J. Exp. Biol., October 15, 2009; 212(20): 3339 - 3348. [Abstract] [Full Text] [PDF]