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.
Blood is circulated around the body by the heart through a system of blood vessels, forming the cardiovascular system. There are 3 kinds of blood vessels: arteries carry blood â¦ away from the heart to body; veins carry blood from the body to the heart; and capillaries carry blood in between tissues. The four-chambered heart acts as a pump and is the centre of the circulatory system.