Skeletal muscle refers to all muscles that are responsible for voluntary movements. This includes not only muscles that are directly adjacent to the skeleton. For example, the arm, leg, and shoulder muscles also fall under the umbrella term.
What is skeletal muscle?
Muscles that enable active movement of the body are part of the skeletal musculature. A well-known example is considered to be the tongue, larynx and diaphragm. It is always important that these are muscles for which voluntary control is possible. The task area of the respective muscle is irrelevant. Thus, it does not necessarily have to be a muscle that is responsible for the movement of the skeleton. What is relevant in the first place is whether conscious control is possible. Accordingly, the heart muscles are not part of the skeletal muscles. In contrast to the tongue or the larynx, voluntary control is not possible. Nevertheless, all skeletal muscles have in common that they are connected to the skeleton via tendons or fasciae. However, a direct connection is not necessary. The attachment can be through multiple tendons and fascia.
Anatomy and structure
Depending on the type of muscle, anatomy and structure may differ. Generally, a skeletal muscle consists of muscle fibers that can reach a length of up to 15 centimeters. On the outside, the fibers are surrounded by connective tissue called fascia. In its entirety, a skeletal muscle is also surrounded by connective tissue. From the connective tissue, septa lead inward and gather individual muscle fibers into a bundle. A muscle fiber can itself be subdivided into a number of filaments. These are myofibrils. They run parallel along a muscle fiber and themselves consist of small units. The units are myofilaments. These are protein structures that enable muscle contraction through mutual interaction. The arrangement of the myofilaments plays an important role here. In addition, nerves and blood vessels pass through the skeletal muscle. In addition, there are tendons and adjacent bones.
Function and tasks
Skeletal muscle can be divided into red and white subcategories. The former are muscles with a characteristic red coloration. They have an increased content of muscle fibers, which promotes oxidative energy production. As a result, movements can be performed with greater endurance. This type of musculature plays a particularly important role in endurance athletes. In white skeletal muscle, the proportion of muscle fibers is low. This allows muscles to contract more quickly, which increases the intensity of a movement. Accordingly, white skeletal muscle is considered to be of great importance in the field of strength sports. Specifically, skeletal muscles are responsible for the static and motor functions of the body. They are controlled by motor nerves that connect to the brain or spinal cord. Via the release of electrical signals, there is uninterrupted communication between the muscles and the central nervous system. Depending on the location and characteristics of the muscle, its range of functions can vary greatly. On the whole, the purpose of the skeletal muscles is to keep the body upright and to provide continuous tension. In addition, there is the controlled supply of energy to the body. Specifically, the optimal body temperature is to be maintained through the exercise of muscle. If the body temperature must rise quickly, the skeletal muscles begin to contract briefly and then relax. The process repeats itself several times a second. From the outside, this is perceived as involuntary trembling. It should be noted that only half of the heat generated in this way is used. The rest is responsible for maintaining the muscles themselves. Furthermore, skeletal muscles have the task of influencing personal well-being. Thus, studies have shown that with the help of messenger substances, a skeletal muscle can have an impact on the immune system and fat metabolism.
Diseases and ailments
During life, a number of diseases and ailments can occur in relation to skeletal muscle. These can be divided into inflammatory and non-inflammatory forms. The former form involves complaints with severe pain levels. Inflammation of the skeletal muscles occurs mainly in the extremities.The pain character can be compared to a sore muscle. However, the discomfort increases and can last for a period of several weeks. The cause may be a muscle injury that has not healed completely. A bacterial pathogen eventually causes inflammation. More multifaceted are the non-inflammatory diseases. Muscular dystrophy is particularly widespread. Due to a mutation of the genetic material, defective proteins are inserted. As a consequence, the muscle mass shrinks, resulting in functional impairment. Mitochondrial myopathy also has serious consequences. In this case, damage occurs to the mitochondria. These are elements of a cell that are responsible for maintaining energy production. In mitochondrial myopathy, the skeletal muscle cells can no longer provide energy. Since the energy needs of the muscle cell cannot be met, it becomes damaged and so does the entire skeletal muscle. In addition, skeletal muscle can be damaged by bone disease. A well-known example is osteoporosis. As a result of bone loss, the loading conditions within the body change. Severe muscle pain is the consequence of a disturbed balance. The pain only decreases as the muscles and associated tendons as well as fasciae deteriorate.
