We explain what is the muscular system, its parts and different functions. In addition, how it is classified and muscular diseases.
What is the muscular system?
When referring to the muscular system , we talk about the set of more than 650 different muscles that make up the human body, most of which can be controlled at will and that allow enough force to be exerted on the skeleton to move.
The muscular system of the human being is vast and complex, constituting 40% of the weight of an adult, also generating most of his body heat. Together with the bone system (bones) and the articular system (joints), it constitutes the so-called locomotor system , responsible for movements and displacements of the body.
The muscles that make up this system are in turn composed of cells with a high level of specificity, which gives them specific properties such as elasticity. These cells, called myocytes , can undergo intense stretching and compression without compromising (to some extent) their constitution. This is why muscle fibers are so resistant and elastic.
The muscles are also electrically excitable, and this is how the nervous system controls them.
There are three essential types of muscles:
- Muscles and skeletal or striated . They are called that because under the microscope they have stretch marks, as well as a characteristic long form. In addition, they are those that connect with the bones of the organism and allow the displacement or movement of the extremities.
- Muscles c aríacos . As the name implies, they are the muscles of the heart wall (myocardium), and they are striated muscles with precise characteristics, since they need to be interconnected to be able to contract and expand in a fully synchronized manner.
- Muscles l isos . They are also known as visceral or involuntary, since they are not committed to the voluntary movement of the body, but to their internal functions (autonomic vegetative nervous system). For example, the movement of the intestines or digestive tract, or the opening or closing of the iris in the eye. They are easily recognized as they lack stretch marks like the previous types.
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Parts of the muscular system
The muscular system is made up of a huge variety of muscles, among which we find:
- Fusiform muscles . Those spindle-shaped, thick in the central part and thin at the ends, such as those present in the upper and lower limbs.
- Flat and wide muscles . Present mainly in the abdominal wall, they mobilize and protect the lower internal organs.
- Fan muscles . As the name implies, they are fan-shaped, and two important examples are the pectorals (in the chest) and the temporary ones (in the jaw).
- Circular muscles . They have a ring shape, so they serve to close (when contracting) or open (when relaxing) various ducts, such as the anal opening through which we defecate.
- Orbicular muscles . Similar to fusiforms, but they have a hole in the center, so they allow to open and close other structures. An example is the orbicular muscle in our eyelids.
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Functions of the muscular system
The muscular system is vital for the organism, since it takes care of keeping things moving. For example, the heart is an organ that cannot stop pumping blood, because it would cause us to die.
Therefore, your muscles must be strong and designed for continuous exercise. Similarly, digestive movements, from the trachea to the intestines, are muscular, or respiratory, responsibility.
Second, the musculature allows voluntary movement, which is the best way to deal with the environment for living beings: it allows us to mobilize the skeleton and move to change places, or use our limbs in a specific way and build food, caress our loved ones or defend ourselves from an attacker.
Even gestures as simple as moving our eyes or smiling, are due to the punctual action of some set of body muscles.
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Diseases of the muscular system
Muscles can be affected by ailments of different types, such as:
- Lacerations . Partial ruptures of muscle tissue that, although they can repair themselves over time, usually decrease motor capacity and are extremely painful.
- Cramps . Painful and involuntary contractions of a specific muscle, due to extreme fatigue or imbalances in muscle chemistry.
- Atrophy . Due to prolonged lack of use, diseases or major trauma, the muscles may cease to function and become atrophied, that is, lose the volume of their tissue.
- Poliomyelitis . Produced by a virus , this disease really afflicts the nervous system, but by paralyzing the electrical impulses it causes an artificial atrophy on the musculature.
