Physiological adaptations in diving vertebrates

Abstract

Scope and Method of Study: A review of the literature concerned with physiological adaptations in diving vertebrates was made. The result is intended to serve as a summation of the work done in this area.

Findings and Conclusions: Diving vertebrates show some adaptations to the threat of asphyxia due to prolonged dives. The most universal adaptation is bradycardia or slowing down of the heart rate. This has been shown to occur in nearly all diving animals studied, and also in some non-diving animals. Along with the bradycardia, vasoconstriction is also found. The muscles, kidneys, intestines, and other areas show the constriction. The heart and brain, which have very little tolerance for anoxia, during this time has normal or even increased blood flow. Reduction of metabolic rate in the peripheral tissues is another adaptation found in the diving vertebrates. The results of the adaptation is to reduce the diving animal to a heart-brain-lung preparation. The effect is to provide the tissues that are not tolerant to asphyxia - the heart and brain - with the most optimum environment possible under diving conditions.

Some other adaptations found in other diving vertebrates are also reviewed in the manuscript.