Physiology of Finfish and Shellfish

2.2.25. Circulatory system of crustaceans -Introduction

The circulatory system distributes nutrients, respiratory gases, metabolic castes and hormones through out the body. in crustacean the circulatory system is open that is the blood and its circulating cells directly perfuse all tissues. In lobster, the blood is called as hemolymph and the circulating system involving cells are called as hemocytes. Although there is an elaborate system of vessels carrying hemolymph from the heart to the tissues, the vessels eventually terminate. There are no beads of capillieries for exchange. Generally, the hemolymph then flows into large open spaces (sinuses), bathing the tissues directly, with no intervening capillary walls. The open circulatory systems have traditionally been considered sluggish with low pressure and little regulation of flow patterns. The goal of this chapter to summarise the current knowledge of

1. The morphology and function of the structure comprising the open circulatory system including the heart, vessels and sinuses.
2. The cellular and cellular components of the hemolymph and their functional roles.
3. Hemolymph – borne diseases.