About Bio 既問題....無限個急!!!!!

(1) 心臟病同心絞痛有咩分別???
P.S : 有人話係有分別....but 我睇書果陣....D 解釋係冇分別囉
因為心絞痛係心臟病既其中一種病徵.
(2) Why 換氣過度 & 打斯 egg果陣..... 可以用膠袋封住口&鼻....
吸番自己放出黎既氣....甘就冇事????
因為身體測出過低既二氧化碳, 腦中血管會收縮, 導致暈眩. 詳見 http://en.wikipedia.org/wiki/Hyperventilation
用膠袋封住口&鼻, 可以吸返頭先呼出既空氣, 令肺中二氧化碳增加, 而達致減退不適.

If carbon dioxide levels are high, the body assumes that oxygen levels are low, and accordingly, the brain's blood vessels dilate to assure sufficient blood flow and supply of oxygen. Conversely, low carbon dioxide levels (e.g. from hyperventilation) cause the brain's blood vessels to constrict, resulting in reduced blood flow to the brain and lightheadedness. The alkalinization of blood due to hypocapnia is the mechanism by which vessels constrict; it is theorized that myofibrillar calcium sensitivity is increased in the presence of low hydrogen ion concentration.