This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pathology
In Raynaud's phenomenon which of the following change is seen in vessels in initial stage? 
Select and explain. 
A. No change, B. Thrombosis, C. Fibrinoid necrosis, D. Hyaline sclerosis
A: No change
Answer: A: No change 
Explanation: Raynaud phenomenon results from the exaggerated vasoconstriction of aeries and aerioles in the extremities, paicularly in the fingers and toes. The restricted blood flow induces paroxysmal pallor or cyanosis; involved digits characteristically show " red-white -and-blue " color change most proximal to most distal Robbins 9 th edition page no. 355