關於血管的問題

首先，我們可從皮膚表面所見到的一定不是 Artery (動脈)，應該是 vein (靜脈)。
除了pulmonary and umbilical arteries，artery 都係carry oxygenated blood (Bright red).
Vien carries deoxygenated blood (dark red).
所以，平時皮膚表面所見到深紫紅血管，應都不是artery。

第二，幫助散熱的血管只有capillary，該名為 vasodilation。
Vasodilation is a process by which blood vessels in the body become wider following the relaxation of the smooth muscle in the vessel wall. This will reduce blood pressure - since there is more room for the blood.

Vasodilation also occurs in superficial blood vessels of warm-blooded animals when their ambient environment is hot; this process diverts the flow of heated blood to the skin of the animal, where heat can be more easily released into the atmosphere. The opposite physiological process is vasoconstriction.

判斷正確! 但人體係一個精密科學, 綜合結構一體化, 係屬於綜合結合的成果.