PHYsioloSICS 物理生理学 What a weird word, bizarre like a genetic mutation

Actually, in my opinion PHYsioloSICS should be BioPhysics. But since I hardly understand the biophysics text therefore I dare not use the word BioPhysics, which is quite high end for me. I used to own a Physics textbook for my matriculation study, it was not until middle of year 2 that i discovered the hidden treasure in it, where it involves the discussion of various aspect of Physics knowledge application in Medicine. I like it when 2 unrelated things come together beautifully like a massive integration. I am quite rebellious perhaps, but i truly treasure the moment of excitement when unrelated thing merge together !

A DoMicMousMon ? Doreamon always afraid of mouse! yet this is a creative combination of Doreamon and Mickey mouse.

Okay let's get back to the stem. In this passage, I wish to share my excitement learning pathophysiology of arteriosclerosis from a Physics textbook instead of Physiology or Pathology textbook. Below are my reply to my colleague in our discussion about Artherosclerosis 动脉粥样硬化. Wow it is quite surprise for me to find out the mandarin translation of artherosclerosis! 动脉 means artery, 粥样 from my understanding it is porridge like? 硬化 means sclerosed. why it is porridge like? perhaps i will find out more!

In a person with advanced arteriosclerosis, the Bernoulli effect produces a symptoms called vascular flutter. in this condition the artery is constricted as a result of accumulated plaque on its inner walls. To maintain constant flow rate (recap physiology. Flow[also known as flow rate] = Volume/time. Velocity = displacement/time = Flow / Area[also known as radius or diameter]. from the equation: Flow = Velocity x Radius, decrease in radius must increase velocity), the blood must travel faster than normal through the constriction. If the speed of the blood is sufficiently high in the constricted region, the blood pressure is low (this is Bernouli principle. recall pre-u physics model of venturi tube) and the artery may collapse under external pressure(outside vessel) causing momentarily interruption in blood flow. During the collapse there is no Bernouli effect, so the vessel reopens under arterial pressure. As the blood rushes through the constricted artery, the internal pressure drops and the artery closes again. such variation in blood flow can be heard with a stethoscope.

An aneuryms is a weakened spot on artery where the artery walls have ballooned outward. blood flows more slowly through this region, as can be seen from the equation of continuity A1v1 = A2v2, resulting in an increase in pressure in the vicinity of the aneurysm relative to the pressure in other parts of the artery. This condition is dangerous because the excess pressure can cause the artery to rupture. [can see from Laplace Law: Pressure = 2Tension/ Radius => Tension = Pressure x Radius. increase radius and pressure will increase tension on the already weakened vessel wall and rupture occure]

Reference: Vuille/Serway College Physics 8th edi

With Metta :)