Structure and innervation of retia mirabilia of Bottlenose dolphin (Tursiops truncatus)

Abstract

Although the circulatory systems of marine mammals follow the general mammalian plan, they are most notable for features associated with the diving response, thermoregulation, and large body mass. This chapter will emphasize anatomical and functional aspects of the circulatory system in these animals. The cardiovascular reflexes and adjustments which occur during diving are reviewed in the chapter Diving Physiology. Specific features of the circulatory system vary with orders, families, and species. These adaptations include large blood volumes, large capacitance structures (spleens and venous sinsuses), venous sphincter muscles, vascular adaptations for thermoregulation, aortic windkessels, and vascular retia. The heart, arterial and venous systems, and blood volume will be discussed first. Then specific structural adaptations of the circulation in various groups will be considered.