What are venules?

venules are a type of blood vessels found in the circulatory system. All blood vessels transport blood either from the heart to the body or from the body back to the heart. Tits and arteriols transport blood from the heart to the body while the veins and venules transport blood back to the heart. When the blood vessels come further from the heart, they branch and create smaller blood vessels. The capillaries are the smallest blood vessels. They are just strong cells and their walls are also very thin. This allows oxygen to move from the blood to the surrounding cells and carbon dioxide moves from the cells to the blood. Smaller arteriols and venules are branched. The capillaries act as a connection between arterioles and venules, which makes the circulatory system a complete system for blood flow. The vein is much larger than the venue and can carry a much higher volume of blood. Many venules connect with a single vein to transport blood.

Most of the blood that is transported by venules is deoxygenatedblood. This means that the blood passing through various tissues and organs in the body and oxygen has switched from blood to the body cells. Blood must now travel back to the lungs to pick up more oxygen to return to the body.

When blood leaves the heart, it is drawn around the body by the hearts of the heart, but the same does not apply to the return of blood to the heart. Blood flow in the veins and Venuly is much slower than in the arteri and arteriol. In fact, blood is drawn by contractions on the limbs, such as legs.

Most blood flows against gravity as they travel back to the heart and lungs. In each venule and vein are present semi-lunar valves to prevent blood flow back down the vein or venule. These valves are necessary because the blood is not pumped so hard and counteracts the effects of gravity on slower moving blood.