Final answer:
A thrombus originates in a cerebral blood vessel, while an embolus originates elsewhere and lodges in a cerebral blood vessel. When a portion of a thrombus breaks free from the vessel wall and enters the circulation, it is referred to as an embolus.
Step-by-step explanation:
A) True
A thrombus originates in a cerebral blood vessel, while an embolus originates elsewhere and lodges in a cerebral blood vessel. When a portion of a thrombus breaks free from the vessel wall and enters the circulation, it is referred to as an embolus. An embolus that is carried through the bloodstream can be large enough to block a vessel critical to a major organ, causing medical emergencies like heart attacks, strokes, or pulmonary embolisms.