Five photos of real abdominal muscles of junior middle school boys

Muscles help us fight gravity. Muscle fibers control every movement, from blinking to smiling. Thousands of tiny fibers are assembled into muscle bundles, thus forming a complete muscle system.

Take rock climbers as an example. Every step of climbing requires the elastic expansion and contraction of muscles. Muscles can only be pulled, not pushed, and most of them belong to skeletal muscles. They are connected by tendons and bones, and the closely combined tendon fibers have the function of rubber bands.

Muscles can affect the eyes, so that we can see things clearly, blink and blink; The muscles of the hands and fingertips enable us to hold very small objects. Take rock climbers as an example, they need to hold something to fix themselves, and continuous muscle contraction can keep them climbing.

Extended data:

There are many naming principles for muscles, mainly including:

① According to the shape, such as trapezius muscle and deltoid muscle;

② According to the location, such as supraspinatus, infraspinatus, tibialis anterior, intercostal muscle, etc.

③ Press the starting and ending points, such as sternocleidomastoid muscle and sternohyoid muscle;

④ According to the position and size, pectoralis major, pectoralis minor, psoas major, etc.

(5) According to actions, such as supinator, adductor, flexor and extensor. ;

⑥ According to the structure, such as semitendinosus and semitendinosus;

⑦ According to structure and position, biceps brachii, quadriceps femoris and so on. ⑧ According to the position and fiber direction, such as external oblique muscle and transverse abdominal muscle.