What is a Striated Muscle?

Striated muscle: The muscle fibers of skeletal muscle and myocardium have light and dark stripes. Therefore, it is called striated muscle, also known as skeletal muscle. It is composed of multi-core bundled striated muscle fibers. It is the main component of each skeletal muscle. ingredient. It is named because it is mainly attached to bones, and when viewed under a microscope, it shows light and dark stripes. In addition to being innervated by the nerves, it is also controlled by consciousness to complete various voluntary movements of the human body, so it is also called voluntary muscle.

Striated muscle: The muscle fibers of skeletal muscle and myocardium have light and dark stripes. Therefore, it is called striated muscle, also known as skeletal muscle. It is composed of multi-core bundled striated muscle fibers. It is the main component of each skeletal muscle. ingredient. It is named because it is mainly attached to bones, and when viewed under a microscope, it shows light and dark stripes. In addition to being innervated by the nerves, it is also controlled by consciousness to complete various voluntary movements of the human body, so it is also called voluntary muscle.

Chinese name

Striated muscle

Also known as

Skeletal muscle

Striated muscle overview

The striated muscle fibers are slender and cylindrical, with different lengths and shortest lengths of only 1 mm. For example, the muscle fibers of the stapedius muscle can grow to more than 10 cm in length. The average length is about 3 to 40 mm. The average diameter of muscle fibers is about 10 to 100 microns.

A type of muscle tissue. It is named for muscle fibers showing horizontal stripes. There are many myofibrils in the cytoplasm that are parallel to the long axis of the myofibers, and each myofibril is composed of finer filaments and filaments. Thick filaments are composed of myosin, also known as myosin filaments; thin filaments are composed of actin, also known as actin filaments. The thick and thin filaments are parallel and regularly arranged in the myofibrils, showing very consistent light and dark horizontal stripes under the microscope. The contraction and relaxation of the striated muscle is caused by the thick and thin wires sliding on each other, thereby changing the length of each sarcomere. According to the different distribution and structure, it is divided into two types: skeletal muscle (see "skeletal muscle") and cardiac muscle (see "cardiac muscle").

Also called "skeletal muscle". Because most of them attach to the bones. Skeletal muscle is an important part of the motor system. Its contraction can produce various voluntary movements of the dog's body. Every muscle distributed in the dog's body is an organ, and many parallel muscle fibers pass through connective tissue. Assembled. The connective tissue referred to here is the myometrium and the tendon.

The sarcolemma is divided into three types: endomyocardium, sarcolemma, and epicardium. Outside each muscle fiber, it encloses a thin and soft connective tissue membrane, which is the endomysium; many muscle fibers gather into small muscle sacs, and the periphery is surrounded by a layer of connective tissue membranes, which are muscle sac membranes; many muscle sacs The muscles assembled into a certain shape are covered with a thick layer of connective tissue membrane. Tendons are made up of tendon fibers. These tendon fibers are directly connected to the ends of the muscle fibers or run through the beginning and end of the muscle, and mainly form the fixed part of the muscle. Each muscle has a rich distribution of blood vessels and nerves to provide nutrition, regulate muscle activity, and maintain various postures and movements of the dog. In addition, muscles can be divided into extensors and flexors, adductors and abductors, supinator and pronator, sphincter, etc. based on the effects of muscle contraction. According to the shape of the muscle, it can be divided into long muscle, short muscle, broad muscle and orbicularis muscle. The muscles are divided into head muscles, trunk muscles, and limb muscles.

Striated muscle anatomy

The muscle cell membrane is a homogeneous thin film, transparent and elastic. Multi-nucleus, some muscle fibers can have up to hundreds of nuclei, located at the edge of the cell, close to the cell membrane. In addition to general organelles, sarcoplasm also contains a large number of myofibrils and energy material structures with contractile functions, such as mitochondria, sarcoplasmic reticulum, lipid droplets, and glycogen.

The physiological characteristics of striated muscles are fast response to stimuli and large contraction power, but it also consumes large energy, so it is easy to fatigue, and the contraction is difficult to last. Its stretching performance is not as good as smooth muscle. The striated muscle originates from the mesoderm and has a low regeneration capacity. Recent studies have shown that when striated muscle is injured, satellite cells located on the surface of striated muscle can divide and reproduce, evolve into myoblasts, and transform into muscle cells. Some experimental studies also believe that some cells of connective tissue can also differentiate into myoblasts, but further research has yet to confirm.

Striated muscle and striated muscle-related diseases and their clinical treatment

1. Rhabdomyolysis: also known as osteofascial compartment syndrome, which refers to the syndrome caused by acute ischemia of the muscles and nerves in the osteofascial compartment due to trauma or improper post-traumatic treatment. Different lesions can be caused by the scope, degree and cause of ischemia, such as Volkmann ischemic muscle contracture, frequent ischemic muscle contracture, crush syndrome, exercise ischemia, etc. . It can be seen in injuries, edema after ischemia, strenuous exercise, tight bandaging after trauma, and long-term local compression, which are manifested as pain, tenderness, local swelling, high skin temperature, flexion of fingers (toes), and reduced flexion and extension. However, the filling time and pulse of the distal capillaries were normal. If not handled in time, there may be systemic symptoms, such as fever, pulse rate, myosin in the urine, and so on. Ischemic muscle contractures can be changed from pain to painless, pale or cyanotic, variegated, paresthesia, muscle paralysis, and pulselessness.

Once the symptoms are diagnosed, decompression should be cut as early as possible to prevent ischemic necrosis of muscles and nerves. After decompression and decompression, water, electrolyte imbalance, hyperkalemia and renal failure, heart rhythm disorders, shock, etc. should be actively prevented. Amputations should be taken to save lives if necessary.

2. Rhabdomyosarcoma: A tumor that originates from rhabdomyoblasts. Very rare, there are many young people, mostly benign, can occur in the heart, skeletal muscle, vaginal wall, kidney, bladder and other organs or tissues. Cardiac rhabdomyosarcoma is more common in infants. Almost all tumor cells contain glycogen, and there are radial stripes in the cytoplasm and vacuoles containing glycogen. The clinical manifestations vary depending on the location of the disease, and those who develop in the heart are difficult to diagnose and have a poor prognosis. rare. Occurs in the heart muscle, often accompanied by nodular sclerosis of the brain, is actually a congenital malformation, rhabdomyomas outside the heart often in the soft tissue of the head and neck. Is a benign fibroid. Tumors formed by striated muscle cells or striated myoblasts can occur in skeletal muscle, heart muscle, kidney, bladder, vagina, etc. Tumor cells are sometimes larger and contain glycogen. Clinical manifestations: Symptoms are less obvious when the tumor is smaller, and obstruction or compression symptoms are larger when the tumor is larger. X-ray examination is helpful for diagnosis, and pathological examination can confirm the diagnosis. Treatment: based on surgical resection.

Clinical manifestations: Skin lesions are usually deep, and patients rarely see a dermatologist. Extracardiac rhabdomyosarcoma can be divided into 3 types: adult rhabdomyosarcoma, more common in older men, which occurs in head and neck muscles or mucous membranes, such as oral cavity, pharynx, and throat; fetal rhabdomyosarcoma, almost all infants, under 3 More common in boys, tumors are common in the face and neck, especially under the ears and around the eyes subcutaneously, and may also involve the upper respiratory tract; genital rhabdomyosarcoma, manifested as cervical, vaginal or vulvar polyps, more common in young women.

Histopathology: The tumor boundary is clear, and pseudo-envelope formed by connective tissue is common. The adult type is composed entirely of rhabdomyoblasts, with large cells, abundant cytoplasm, and rich in glycogen. Fetal and genital types are composed of immature rhabdomyoblasts, which are round or spindle-shaped. The surrounding cells are relatively mature, similar to fetal muscle, and the cells are located in a mucus-like matrix.

Rhabdomyosarcoma types and common population

Rhabdo myo sarcoma (RMS) is one of the relatively rare soft tissue malignancies. According to its clinical and pathological characteristics, WHO divides it into 4 subtypes: embryonic rhabdomyosarcoma and acinar striated muscle Sarcoma (alveolar rhabdomyosarcoma), pleomorphic rhabdomyosarcoma and sclerrosing rhabdomyosarcoma. Among them, the former two are more common in children and adolescents, and the polymorphism is more common in the elderly; sclerosing rhabdomyosarcoma can be affected by both children and adults. It is a rare type, accounting for 5% to 10% of rhabdomyosarcoma Most rhabdomyosarcoma can be diagnosed by morphology and immunohistochemistry. For some poorly differentiated cases, especially some acinar rhabdomyosarcoma, the diagnosis is difficult. Some foreign studies have shown that acinar rhabdomyosarcoma has specific FOXO1 gene isolation, which is of great significance for tumor classification.