What part of you is only 1% to 3% of your body’s mass，yet uses 20% of all the oxygen you breathe? Your brain! Here are three brain facts.

1.Your brain needs a continuous supply of oxygen. A 10 minute loss of oxygen will usually cause significant neural damage. Cold can lengthen this time， which is why coldwater drowning victims have been revived after as much as 40 minutes—without brain damage.

2.Your brain uses a fifth of all your blood. It needs it to keep up with the heavy metabolic demands of its neurons. It needs not only the glucose， but of course， the oxygen.

3.Your brain feels no pain. There are no nerves that register pain within the brain itself. Because of this，neurosurgeons can probe the brain while a patient is conscious (what fun!). By doing this， they can use feedback from the patient to identify important regions， such as those used for speech， or visualization.

你身體的哪個部分只占身體總質(zhì)量的1%~3%，卻要消耗掉你所吸的20%的氧氣?是你的大腦!以下是三個關(guān)于大腦的事實#65377;

1.大腦需要不斷供氧，缺氧十分鐘就會造成嚴重的神經(jīng)損傷#65377;寒冷可以延長這個時間，這就是為什么在冷水中溺水長達40分鐘的人依然可以被救活，而且沒有造成腦損傷#65377;

2.人類大腦中有約十萬英里長的血管#65377;如果將它們伸展開來，可環(huán)繞地球四圈多#65377;

3.大腦感覺不出疼痛，因為大腦中沒有感知疼痛的神經(jīng)#65377;因此，神經(jīng)外科醫(yī)師可以在患者清醒時用探針對其大腦進行探查(多有意思!)#65377;這樣，他們可以利用患者的反饋來鑒定大腦的重要區(qū)域，如那些控制言語和視覺的區(qū)域#65377;