Arterial blood oxygen saturation of haemoglobin. The difference in the oxygen content of the blood between the arterial blood and the venous blood is known as the arteriovenous oxygen difference. Arterial blood Arterial blood is the oxygenated blood in the circulatory system found in the pulmonary vein, the left chambers of the heart, and in the arteries. It is bright red in color, while venous blood is dark red in color (but looks purple through the translucent skin). It is the contralateral term to "venous blood". Framed in the cardiac cycle, often historically accredited to the Wiggers diagram, arterial blood has just
Azygos vein its left-side equivalent. This terminology is only accurate in some species, such as the human, dog and cat. Ruminants (such as sheep and cows) have paired azygos veins. Azygos vein The azygos vein is a vein running up the side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superior vena cava and inferior vena cava and can provide an alternative path for blood to the right atrium when either of the venae cavae is blocked. The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into