The great vessels are mainly located in the thoracic and abdominal cavities and in the limbs and neck. Large blood vessels are mainly composed of large arteries and large veins. 1. Large arteries generally have a large diameter and are round, mainly: 1) aorta, pulmonary artery, etc. are generally located in the thoracic and abdominal cavities. 2) innominate artery, common carotid artery, etc. are located in the neck. 3) common iliac artery and femoral artery, etc. are located in the lower extremities. 4) axillary artery, brachial artery, etc. are located in the upper extremities. 2. The large veins, including the superior and inferior vena cava and pulmonary veins, are generally located in the thoracic and abdominal cavities. The corresponding veins of the limbs are generally accompanied by arterial pathways. The great arteries are the main conduits that deliver blood to all parts of the body, and the walls of the tubes are rich in elastic fibers, also known as elastic arteries. The role of the great veins is to guide blood back to the heart, also known as volume vessels.