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The muscle and the skeletal system with the aid of the nervous system enable us to move． The muscle consists of bundles of muscle fibres which bound together by connective tissues． Nerves and large blood vessels are located between the bundles． Capillaries supply the muscle fibres with nutrients and oxygen and remove waste products．Muscles are activated by nerves and impulse from the brain and are sent to the spinal cord via the nerve fibres and to the muscle which contract．
肌肉和骨骼系统在神经系统的作用下使得人体能够活动。结缔组织将若干束肌纤维组合在一起构成肌肉，在这些肌纤维之间有许多神经和大量血管。毛细血管给这些肌纤维提供氧气和养料并运走废物。肌肉运动是在大脑神经与冲动的作用下产生的。通过神经纤维，大脑神经与冲动被传至脊髓，再传向肌肉并使肌肉产生收缩。
At each end of a muscle are one or more tendons which connect the muscle to the skeletal system． ［2］ When the muscle contracts the end of the two tendons move towards each other and the bones to which they are attached rotate around the skeletal joint and movement occurs． ［3］ e． g． the quadriceps muscle，theorigin of which is attached to the pelvis，goes over the femur and over the knee and is attached to the tibia． When we kick a ball the quadriceps muscle contracts and the leg is swing forward and thus the kicking action．
在每块肌肉两端有一个或多个肌腱，这些肌腱将肌肉和骨骼连在一起。肌肉收缩时拉动肌腱的两端相互靠近，于是与肌腱相连的骨骼围绕关节旋转，这样就完成了一个动作。例如四头肌上端与骨盆相连，贯穿大腿骨和膝关节，下端与胫骨相连。踢球时，四头肌收缩，大腿向前摆动，这样就完成了一个踢球动作。
