CARDIOVASCULAR SYSTEM
The heart lies in the midline, slightly caudal to the pectoral girdle in a pericardial cavity and separate from the cranial part of the ventral body cavity. It is three chambered with an incomplete ventricular septum, although functional pulmonary and systemic circulation is separate.
The aortic arches are paired. The left aorta gives rise to a celiac, left gastric and cranial mesenteric artery before joining the right aorta caudal to the heart. Like all reptiles, venous drainage from the pelvic limb drains into the kidney to form the renal portal system.Venepuncture sites
(Murray 2000; Redrobe & MacDonald 1999)
Jugular vein - This lies very superficially on the lateral side of the neck and runs from the tympanic membrane at the angle of the jaw to the base of the neck (Fig. 3.17).
Dorsal coccygeal vein - The coccygeal vertebrae lack dorsal spines and the vein runs quite superficially.
Figure 3.17 • Blood sampling from jugular vein in a Spur-thigh tortoise (Testudo graeca).
Dorsal occipital venous plexus - This sinus cannot be visualized. The head is extended and needle inserted lateral to the cervical vertebrae, just cranial to the carapace. It is the best location in marine turtles.
■ Toenail - This is least recommended as it is painful and samples can be contaminated with urates. a lymphatic ring around the base of the neck (Ottaviani & Tazzi 1977) (Fig. 3.18).