CDQuizAns

# CDQuizAns - 7B Quiz 1 Last 6 digits of ID Name Signature DL...

This preview shows pages 1–3. Sign up to view the full content.

7B Quiz 1 Name: DL Sec. Last 6 digits of ID # Signature: Physics 7B Quiz 1 Spring Session 2008 Larger human arteries (left figure below) are typically elastic, so the artery walls are supported against the pressure of the surrounding tissue by the blood within them. In FNT 5.1-6 you considered an aneurysm, an abnormal enlargement of a section of an artery. A cholesterol plaque is a deposit which can form in an artery and result in an abnormal narrowing of a section of artery (second figure from left). Two surgical treatments are possible. The first is to place a stent , a thin wire mesh tube, inside the artery to hold it open (second figure from right). The second is a bypass , in which another artery is placed parallel to the narrowed section of original artery (right figure). 1) The stent is used to keep the artery from collapsing under the pressure of the surrounding tissue. This is not a danger in a healthy artery. Why is it a problem when a cholesterol plaque has narrowed the artery? Use the models we have learned about in class to explain this. Which term(s) in the equations we have been using are involved in your explanation, and how? 2) Now consider the treatment by the use of a bypass. How does this treatment work to improve the supply of blood to the heart? Use the models we have learned about in class to explain this. Which term(s) in the equations we have been using are involved in your explanation, and how? Answer: Note that the bypass increases the total cross section from point 3 to point 4. This reduces the speed of the blood through the diseased region in general, with the result that the danger of collapsing the region with the plaque is reduced.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document