The Decapod Crustacean Circulatory System: A Case That Is neither Open nor Closed

Abstract

Historically, the decapod crustacean circulatory system has been classed as open. However, recent work on the blue crab, Callinectes sapidus, suggests the circulatory system may be more complex than previously described. Corrosion casting techniques were refined and used to map the circulatory system of a variety of crab species (order: Decapoda; family: Cancridae) to determine if the complexity observed in the blue crab was present in other species. Seven arteries arose from the single chambered heart. The anterior aorta, the paired anterolateral arteries, and the paired hepatic arteries exited from the anterior aspect of the heart. The small-diameter posterior aorta exited posteriorly from the heart. Exiting from the ventral surface of the heart, the sternal artery branched to supply the legs and mouthparts of the crab. These arteries were more complex than previously described, with arterioles perfusing all areas of the body. The arterioles split into fine capillary-like vessels. Most of these capillaries were blind ending. However, in several areas (antennal gland, supraesophageal ganglion) complete capillary beds were present. After passing through the capillary-like vessels, blood drained into a series of sinuses. However, rather than being arbitrary spaces as previously described, scanning electron micrographs showed the sinuses to be distinct units. Most of the sinuses formed a series of flattened membrane-bound lacunae. This complexity may qualify the decapod crustacean circulatory system as one that is "partially closed" rather than open.

Does feeding limit cardiovascular modulation in the Dungeness crabCancer magisterduring hypoxia?

“…This feeding method also aimed to reduce some of the activity associated with feeding (apparent specific dynamic action; Carefoot, 1990). Nevertheless, the crabs still moved the mouthparts and chelae when food was administered: this was seen as an increase in flow through the sternal artery (Fig.·2E), which supplies these structures (McGaw, 2005). Haemolymph flow rates through the hepatic artery (which supplies the hepatopancreas) increased 3·h after feeding, which corresponds closely with the time that protein synthesis increases in the hepatopancreas (Houlihan et al, 1990).…”

“…The anterior aorta was the only artery in which flow was maintained (Figs·4A, 6A). This artery supplies the supraoesophageal ganglion of the crab (McGaw and Reiber, 2002;McGaw, 2005) so it is important to maintain a blood supply to this organ. The general decrease in haemolymph flow is the opposite to the pattern occurring in feeding alone (Fig.·2); thus digestion must be slowed, prioritizing blood flow for other processes.…”

Oxygen delivery does not limit thermal tolerance in a tropical eurythermal crustacean

“…The lack of reduced oxygen transport capacity at high temperatures may in part be due to the cardiovascular anatomy of crustaceans. The single-chambered crustacean heart is situated within the pericardial sinus and supplied with oxygen-rich hemolymph entering the heart through ostia from the gills (McGaw, 2005). This is in contrast to…”

Symmetry variation in the heart‐descending artery system of the parthenogenetic marbled crayfish

“…It gives rise to seven arteries that lead into different body regions, five originating anteriorly and two posteriorly. The antennary and hepatopancreatic arteries are generally paired, the anterior aorta and the posterior aorta are generally unpaired, and the descending artery is usually unpaired but occasionally paired (Baumann, 1921;Wilkens et al, 1997;Wilkens, 1999;Vogt, 2002;McGaw, 2005).…”

“…Of the seven arteries that leave the heart the descending artery has been shown to receive the highest cardiac output by far (Reiber, 1994;McGaw, 2005), underlining its functional significance. On its way from the heart to the subneural artery the descending artery usually loops around the left or right side of the centrally located gut (hindgut in crayfish, midgut in other decapods).…”