Lesson plan
Collateral circulation
Collateral circulation is the alternate circulation around a blocked artery or vein via another path, such as nearby minor vessels. It may occur via preexisting vascular redundancy (analogous to engineered redundancy), as in the circle of Willis in the brain, or it may occur via new branches formed between adjacent blood vessels (neovascularization), as in the eye after a retinal embolism or in the brain when an instance of arterial constriction occurs due to Moyamoya disease. Its formation may be related by pathological conditions such as high vascular resistance or ischaemia. It is occasionally also known as accessory circulation, auxiliary circulation, or secondary circulation. It has surgically created analogues in which shunts or anastomoses are constructed to bypass circulatory problems. An example of the usefulness of collateral circulation is a systemic thromboembolism in cats. This is when a thrombotic embolus lodges above the external iliac artery (common iliac artery), blocking the external and internal iliac arteries and effectively shutting off all blood supply to the hind leg. Even though the main vessels to the leg are blocked, enough blood can get to the tissues in the leg via the collateral circulation to keep them alive.
Article summary
Collateral circulation is the alternate circulation around a blocked artery or vein via another path, such as nearby minor vessels. It may occur via preexisting vascular redundancy (analogous to engineered redundancy), as in the circle of Willis in the brain, or it may occur via new branches formed between adjacent blood vessels (neovascularization), as in the eye after a retinal embolism or in the brain when an instance of arterial constriction occurs due to Moyamoya disease. Its formation may be related by pathological conditions such as high vascular resistance or ischaemia. It is occasionally also known as accessory circulation, auxiliary circulation, or secondary circulation. It has surgically created analogues in which shunts or anastomoses are constructed to bypass circulatory problems. An example of the usefulness of collateral circulation is a systemic thromboembolism in cats. This is when a thrombotic embolus lodges above the external iliac artery (common iliac artery), blocking the external and internal iliac arteries and effectively shutting off all blood supply to the hind leg. Even though the main vessels to the leg are blocked, enough blood can get to the tissues in the leg via the collateral circulation to keep them alive.
Key claims
No claims recorded.
Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
No sources recorded.
Key claims and bibliography are generated from the same tracked claims and sources as the article page.