A B-double or consists of a prime mover towing two semi-trailers, where the first semi-trailer is connected to the prime mover by a fifth wheel coupling (aka 'converter dolly') and the second semi-trailer is connected to the first semi-trailer by a fifth wheel coupling.
1 Arteries. 2  Arteries are elastic vessels that transport blood away from the heart. 3  Pulmonary arteries carry blood from the heart to the lungs where oxygen is picked up by red blood cells. 4  Systemic arteries deliver blood to the rest of the body. 5  Veins. 6  Veins are elastic vessels that transport blood to the heart.
Efferent vessels are blood vessels that bring blood away from the heart. The arteries are such blood vessels. Arteries carry blood away from the heart. Most arteries carry oxygen-rich blood. The pulmonary artery is an exception - it carries deoxygenated blood from the heart to the lungs. The arteries are connected to the capillaries through the arterioles.