What type of blood do veins typically transport?

Veins typically transport deoxygenated blood back to the heart after it has delivered oxygen to the tissues and collected carbon dioxide and other waste products. This is a crucial part of the circulatory system's function. After oxygen is used by the body's cells, the blood, now low in oxygen and high in carbon dioxide, returns to the heart through the veins.

The key distinction to understand is that, in the systemic circulation, arteries carry oxygen-rich blood away from the heart to various tissues, while veins are responsible for carrying deoxygenated blood back to the heart. In the case of the pulmonary circulation, veins carry oxygenated blood from the lungs to the heart, but on the whole, veins are primarily associated with returning deoxygenated blood in the systemic circuit. This makes it clear why the identification of veins as carriers of deoxygenated blood is foundational in understanding cardiovascular function.