Frog Circulatory System Wednesday, June 24, 2009

1. Spleen 2. Systemic arches 3. Coeliacomesenteric artery 4. Coeliac artery 5. Mesenteric artery 6. Dorsal aorta 7. Common iliac arteries 8. Posterior vena cava 9. Ventral abdominal vein

	This image shows some of the major blood vessels of a preserved bullfrog. The arteries and veins of dissection specimens are often injected with colored latex to make it easier to visualize the extent of the circulatory system. By convention, arteries are injected with red latex and veins with blue latex. Arteries are blood vessels that conduct away from the heart, while veins conduct blood toward the heart. Because of this fact, arteries must withstand much greater blood pressure, and are therefore thicker (and easier to find). Note the two major systemic arches that leave the heart and join to form the large dorsal aorta. At this point, the dorsal aorta gives off a short coeliacomesenteric artery that divides into the coeliac artery that goes to the stomach and pancreas and the mesenteric artery that goes to the intestine and spleen. Beyond this point, the dorsal aorta splits into the two common iliac arteries that supply blood to the legs. The two major veins shown on the image are the posterior vena cava, which receives blood from the liver, kidneys and gonads, and the ventral abdominal vein, which receives tributaries from the body wall and urinary bladder, and is formed by the confluence of two pelvic veins that drain the hind limbs.