Check Your Understanding Critical Thinking and Application Questions REVIEW 1 av
ID: 3514370 • Letter: C
Question
Check Your Understanding Critical Thinking and Application Questions REVIEW 1 avid has an ultrasou nearly 90 percent blocked. is so occluded. What do you tell him? nd of his common carotid arteries, which shows that his right common carotid artery is wonders how the right side of his brain is getting enough blood if this artery He 2 Your patient presents with severe abdominal pain. Your team orders a CT scan and discovers a large blood clot lodged in the celiac trunk. What organs could this blood clot potentially affect? Why do you think the clot is causing abdominal pain? 3 Certain drugs cannot be taken by mouth because the entire dose of the drug is destroyed in the liver before it ever reaches the general circulation. Explain why these same drugs can be given by injection, either intravenously or intramuscularly. (Hint: Consider the hepatic portal system.)Explanation / Answer
1. Blood supply to brain is by CIRCLE OF WILLIS. It is composed of the following arteries _
These arteries form an Anastomoses therefore ensures that even if there is blockage along one of them the rest compensates for it.
2. Celiac trunk is an branch of abdominal aorta. It (or it's branches) supplies following organ-
So if there is any blockage in it then it will affect these organs. The abdominal pain is due to ischemia to these organs which cause ischemic injury.
3. By oral route the drug is first absorbed in small intestine and then go to liver. In liver substantial amount of this oral dose gets metabolised therefore effect is less (first pass metabolism).
By IV or other routes the Liver is bypassed (ie drug doesn't go to liver first) therefore metabolism oof deug is minimal (less first pass metabolism). Therefore more drug is available to act on the body.
4. a) Femoral artery ----> Deep femoral artery or Popleteal artery ---> Anterior tibial or prosterior tibial artery --->Fibular artery (if anterior tibial) or Dorsalis pedis artery (if prosterior tibial artery).
b) femoral vein --->external illiac ---> common illiac ---> inferior vena cava ---> Right atrium ---> right ventricle--->pulmonary artery. ( as blood flow in vein is towards heart)
5. The elastic fibers and collagen in tunica media and externa are important for maintainence of vessel structure and strength (or diameter along with smooth muscle). Loss of these structures cause vesel wall to become loose and dilated thus leading to aneurysm.
6. Both anterior and prosterior tibial artery run along tibia, In her case the fracture caused damage to prosterior tibial therefore there is no pulsation. Anterior tibial artery is intact as dorsalis pedis is it's branch and pulsation is present in it. The distal limb is turning pale and cold as there is loss of supply to lower leg distal to injury (due to damage to prosterior tibial) thus leading to cyanosis and ischemia.