Arterial blood 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 passed through the lungs and is ready to boost oxygen to sustain the peripheral organs. The essential difference between venous and arterial blood is the curve of the
Collapsed vein against the plunger of the syringe to check that the needle is in the vein. This will pull the sides of the vein together and, especially if they are inflamed, they may stick together causing the vein to block. Removing the needle too quickly after injecting can have a similar effect. Collapsed veins may never recover. Many smaller veins are created by the body to circulate the blood, but they are not adequate for injections or IVs. Collapsed vein Collapsed veins are a common result of chronic use of intravenous injections. They are particularly common where injecting conditions are less