Blood pressure 血压
As blood moves through the circulatory system it puts pressure on the walls of blood vessels. 当血液移动通过循环系统时，在血管壁上产生压力。
Blood pressure is the amount of force put on blood vessels. 血压是放在血管上力的大小。
It is caused by the blood flow generated by the heart as it pumps, 它是由心脏泵血引起血液流动产生的，
and the resistance that blood encounters as it moves through the enclosed vessel. 当血液移动通过所述密闭容器时遭遇阻力。
When the heart contracts, 当心脏收缩时，
blood is pushed out into the arteries. 血液被推到动脉。
This force pushes against the vessel wall, 这股力量推动血管壁，
making blood flow faster under high pressure. 使血液流在高压下更快。
When the ventricles relax, 当心室放松，
the vessels walls push back and blood flow slows down resulting in lower pressure. 血管壁的回推，血流量下降导致较低的减缓压力。
The constant pumping of the heart maintains blood pressure and supply throughout the body.恒定的心跳保持血压，供应整个身体。