The average person's muscle accounts for 35%-40% of the body weight. The total length of capillary in muscle can reach100000 km, which can circle the earth for two and a half times.
Every muscle that constitutes a motor organ is a complex organ, which consists of two parts: muscle abdomen and tendon.
Extended data:
According to the different structure and function, it can be divided into smooth muscle, myocardial muscle and skeletal muscle, and according to the shape, it can be divided into long muscle, short muscle, flat muscle and orbicularis oris muscle. Smooth muscle mainly consists of internal organs and blood vessels, which has the characteristics of slow contraction, long-lasting and not easy to fatigue. Myocardium constitutes the heart wall, and neither of them contracts with human will, so it is called involuntary muscle.
Skeletal muscle is distributed in the head, neck, trunk and limbs, and is usually attached to bones. Skeletal muscle contracts rapidly, powerfully and easily, and can contract and contract with people's will, so it is called voluntary muscle. Skeletal muscle is striated under microscope, so it is also called striated muscle.
Muscle contraction pulls bones to produce joint movement, which acts like a lever device and has the following functions:
1, balance the lever movement, the fulcrum is between the key point and the force point, such as the upward and downward movements of the atlanto-occipital joint.
2, labor-saving lever movement, its focus is between the fulcrum and the force point, such as the ankle movement when starting to lift the heel.
3, speed lever movement, its force point is located between the key and the fulcrum, such as the movement of the elbow joint when lifting heavy objects.
Source of reference: Baidu Encyclopedia-Muscle