Question

What is true about vein?
A. All veins carry deoxygenated blood
B. All veins carry deoxygenated blood
C. They carry blood from organs towards heart
D. They carry blood from heart towards organs

Answer 1

The walls of veins have three layers: an inner layer, or tunica intima; a middle layer, or tunica media; and an outer layer, or tunica adventitia and each layer has sublayers. Veins are more in number than arteries and have thinner walls because of the lower blood pressure.

Complete Answer:
- The blood vessels which carry blood from different body parts back to the heart are veins. Pulmonary veins do not carry deoxygenated blood. Pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart. Small vessels are called venules. These venules are an elongated portion from the capillaries to continue the supply of blood along with that these venules merge which leads to the formation of veins that performs its function to drain the blood from the capillaries into the veins.

- Veins perform the function to return blood from the organs to the heart. As the Veins are carrying almost 60% of the blood volume they are also called "capacitance vessels". In systemic circulation oxygenated blood is pumped by the left ventricle through the arteries to the muscles and organs of the body, where its nutrients and gases are exchanged at capillaries. After taking up cellular waste and carbon dioxide in capillaries, blood is channeled through vessels that converge with one another to form venules.

- The complete cycle of blood circulation, is followed by The deoxygenated blood is carried by veins to the right atrium of the heart, which transfers the blood to the right ventricle which continues to converge and form the larger veins., where it is then pumped through the pulmonary arteries to the lungs In pulmonary circulation, the pulmonary veins return oxygenated blood from the lungs to the left atrium, which empties into the left ventricle.

Hence, the correct answer is C- They carry blood from organs towards the heart.

Note: Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow. Most veins carry deoxygenated blood from the tissues back to the heart except the pulmonary and umbilical veins, which carry oxygenated blood to the heart.