Fitness knowledge: myocardium, smooth muscle and skeletal muscle

Fitness knowledge: myocardium, smooth muscle and skeletal muscle

　　Muscles are the source of movements for the human body, but the muscles in our body are not the same. Today we will introduce the basic fitness knowledge to you is to understand muscles, classifications, and their structure!

　　The human body's muscle system is composed of three different muscles:

　　Skeletal muscle: Generally, the "muscle" we commonly call refers to skeletal muscle, which is in harmony with the skeletal system. This muscle is connected to the bones by tendons at both ends. Since this muscle usually needs to be controlled by the brain to issue commands, it is called "random muscle"; and the muscle is dissolved After the microscope, the muscle fibers will appear bright and dark cross-borders, so they are also called "stria muscle".

　　Smooth muscle: mainly constitutes the internal organs of the human body (except the heart), such as the walls of the gastric, intestines, blood vessels, etc. There are no transverse lines under the microscope, nor are they controlled by the will.

　　Mynaecology: Only exists in the heart, transverse lines can be seen in the microscope, but they are not controlled by the will and are not easily fatigued.

　　General exercise, what we study is skeletal muscle

　　The human body has about 600 skeletal muscles, accounting for about 36-40% of the body weight. Skeletal muscles are connected to the bones through tendons, and the muscles are oblong Made of columnar muscle cells, it is called "muscle fibers"; a muscle fiber is about 10 to 150 microns in diameter and can be about 1 mm to 30 cm in length.

　　Each muscle fiber is covered by an extremely thin cell membrane. This specialized, thin layer of reticular fiber is called "muscle membrane" or "sarcosal membrane".

　　Several muscle fibers are wrapped by a connective tissue sarcot membrane mixed with collagen and elastic fibers to form a muscle bundle, while several muscle bundles are wrapped by a thick layer of connective tissue "opause membrane" to form a muscle.

　　Fasci is a dense connective tissue that runs through the body, which surrounds muscles, muscle groups, blood vessels, and nerves. There are several types of fascia in it, called shallow fascia, deep fascia and visceral fascia. The outer myoscillus is a type of deep fascia.

　　Skeletal muscle structure

　　A cell of myoscillus fibers usually has hundreds of nuclei, so even if some of them are damaged, it can be repaired and strengthened. During exercise, strength will be generated by the contraction of these filamentous muscle fibers, and the thicker the diameter of muscle fibers can exert greater strength.

　　Muscillus fibers are divided into "red muscle" and "white muscles", which can play different functions during exercise. The number of muscle fibers will not increase, but these muscle fibers can be thicker through training to strengthen them.