Of, relating to, or of the nature of a vein. See examples of venous used in a sentence. In the circulatory system, blood first enters the venous system from capillary beds where arterial blood changes to venous blood.

Blood flow in veins in the legs and lower parts of the body travels upstream against gravity on its way back to the heart. To prevent backward flow of blood, veins contain one-way valves to ensure that รขโ‚ฌยฆ Veins are thin-walled structures inside of which a set of valves keeps blood in the body flowing in one direction. The heart pumps oxygen-rich blood to the bodyรขโ‚ฌโ„ขs tissues through thicker-walled arteries;