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

This Article Figures Only Full Text 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 Similar articles in PubMed 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 Maina, J. N. Articles by Nathaniel, C. Search for Related Content PubMed PubMed Citation Articles by Maina, J. N. Articles by Nathaniel, C.

The Journal of Experimental Biology 204, 2313-2330 (2001)
© 2001 The Company of Biologists Limited

A qualitative and quantitative study of the lung of an ostrich, Struthio camelus

John N. Maina^* and Christopher Nathaniel

Department of Anatomical Sciences, The University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa

*e-mail: 055john{at}chiron.wits.ac.za

Accepted April 24, 2001

The ostrich lung, with its lack of interparabronchial septa, the presence of very shallow atria and exceptional morphometric refinement, structurally resembles those of small, energetic flying birds, whereas it also displays features characteristic of the flightless ratites in which the neopulmo is relatively poorly developed and a segmentum accelerans may be generally lacking. The large size of the bronchial system of the ostrich may help explain the unique shifts in the airflow pathways that must occur from resting to panting breathing, explaining its insensitivity to acid–base imbalance of the blood during sustained panting under thermal stress. The mass-specific volume of the lung is 39.1 cm³kg^-1 and the volume density of the exchange tissue is remarkably high (78.31%). The blood–gas (tissue) barrier is relatively thick (0.56µm) but the plasma layer is very thin (0.14µm). In this flightless ratite bird, the mass-specific surface area of the tissue barrier (30.1 cm²g^-1), the mass-specific anatomical diffusing capacity of the tissue barrier for oxygen (0.0022mlO₂s^-1Pa^-1kg^-1), the mass-specific volume of pulmonary capillary blood (6.25 cm³kg^-1) and the mass-specific total anatomical diffusing capacity for oxygen (0.00073mlO₂s^-1Pa^-1kg^-1) are equivalent to or exceed those of much smaller highly aerobic volant birds. The distinctive morphological and morphometric features that seem to occur in the ostrich lung may explain how it achieves and maintains high aerobic capacities and endures long thermal panting without experiencing respiratory alkalosis.

Key words: ostrich, Struthio camelus, lung, ratite, birds, respiration, size, morphology, morphometry.

This article has been cited by other articles:

				J. N. Maina and J. B. West Thin and Strong! The Bioengineering Dilemma in the Structural and Functional Design of the Blood-Gas Barrier Physiol Rev, July 1, 2005; 85(3): 811 - 844. [Abstract] [Full Text] [PDF]

				A. Fuller, P. R. Kamerman, S. K. Maloney, G. Mitchell, and D. Mitchell Variability in brain and arterial blood temperatures in free-ranging ostriches in their natural habitat J. Exp. Biol., April 1, 2003; 206(7): 1171 - 1181. [Abstract] [Full Text] [PDF]