Final answer:
The right vertebral artery arises from the right subclavian artery, while the left vertebral artery originates from the left subclavian artery. These arteries supply blood to the CNS and contribute to the circle of Willis.
Step-by-step explanation:
The right and left vertebral arteries originate from different vessels but serve similar functions. The right vertebral artery originates from the right subclavian artery, which, in turn, arises from the brachiocephalic artery. Conversely, the left vertebral artery comes directly from the left subclavian artery, which arises from the aortic arch. These arteries play a crucial role in supplying blood to the central nervous system (CNS), passing through the transverse foramina of the cervical vertebrae and entering the cranium through the foramen magnum. They converge to form the basilar artery and also contribute to the circle of Willis, enhancing cerebral circulation.