Our bodies harbor a wide variety of musclesSome are large and powerful, like the ones we use to walk or jump, while others are smaller, for example the muscles that allow us to blink. In total, the human body has more than 600 muscles, and together they account for about XNUMX% of the body's total. 40-50% of body weight of a healthy person.
Muscles are not only used for movement, but are also responsible for maintaining posture, generating body heat and protecting internal organs. There is a main classification of muscles in the human body into three different types based on their characteristics and functions. Below, we will delve into each of them.
Types of muscles in the human body
There are three types of muscles in the human body, each specialized in different functions. These are: skeletal muscles, smooth muscles and heart musclesThe main difference between them lies in whether their contractions are voluntary or involuntary, and the tasks they perform within the body.
Skeletal muscles
The skeletal muscles They are generally attached to bones by tendons, allowing movement of the joints. They are easily recognizable by their characteristic striations, which are due to the organization of the proteins actin y myosin within the muscle fibers. These muscles are responsible for all voluntary movements of the body, such as running, lifting objects or gesturing.
Skeletal muscle tissue is composed of long fibers that can reach more than 30 cm in length. These fibers are organized into fascicles, which in turn are grouped together to form the complete muscle. Throughout their structure, skeletal muscles are irrigated by blood vessels that provide them with the oxygen and nutrients necessary for contraction.
One of the most interesting aspects of skeletal muscles is their ability to adapt to different workloads. Through training and exercise, these muscles can increase in size (a process known as muscle hypertrophy) and improve their ability to generate force. However, they can also become exhausted and accumulate fatigue after prolonged effort.
Among the main functions of skeletal muscles are:
- Body mobility: being attached to the bones, they allow displacement and movement in general.
- Maintaining posture: Many of these muscles work continuously to keep us upright.
- heat production: due to muscle contraction, they generate the body heat necessary to maintain our temperature.
- Organ protection: Some muscles, such as the abdominal muscles, act as a protective barrier for internal organs.
Smooth muscles
Unlike skeletal, smooth muscles They have a smoother, more uniform appearance, which gives them their name. They are not under the voluntary control of the nervous system, meaning they contract automatically to perform essential functions within the body. These muscles are found primarily in the walls of hollow internal organs, such as the stomach, intestines, bladder, and blood vessels.
Some of the tasks that smooth muscles perform are to move food along the digestive tract through processes such as peristalsis, control blood flow by regulating the diameter of blood vessels and adjust pupil size in response to light. Each of these functions is vital to the proper functioning of the body.
Important features of smooth muscles include:
- Slow and steady contractions: They allow processes such as digestion and circulation to take place in a controlled and efficient manner.
- Involuntary: They do not require conscious intervention, ensuring their continuous operation in the background.
- Low energy consumptionSmooth muscles are extremely efficient and do not fatigue like skeletal muscles.
The control of smooth muscles is regulated by the autonomic nervous system, allowing them to act autonomously in response to internal body signals.
Cardiac muscles
El cardiac muscle, Also known as myocardium, is a special type of muscle found only in the heart. Like skeletal muscles, it has striations, but its contraction is involuntary, as is the case with smooth muscles. Its main function is the continuous pumping of blood through the circulatory system, which is vital for supplying oxygen and nutrients to the body's tissues.
One of the most important characteristics of the heart muscle is its ability to self-regulate. This is made possible by the sinoatrial node, a structure that acts as the heart's natural pacemaker, generating electrical impulses that trigger rhythmic contractions of the heart muscle. This system ensures that the heart continues to beat without interruption.
Its main features include:
- Rhythmic and continuous contractions: They allow the heart to maintain an adequate, uninterrupted flow of blood.
- Fatigue resistance: the heart muscle is prepared to work throughout life without rest.
- Regulated by the autonomic nervous system: allows you to adjust the heart rate according to the body's needs in different situations.
Cardiac muscle, unlike skeletal muscle, has cells that are interconnected to each other by intercalated discs, which allows electrical signals to be transmitted rapidly through muscle tissue, ensuring coordinated and efficient contraction of the heart.
An important thing to keep in mind is that, like any other muscle, the heart can also be affected by fatigue. In extreme cases, such as in a myocardial infarction, a part of the heart loses its ability to contract, compromising blood pumping.
In short, muscles are essential to the functioning of the human body. From the voluntary movements controlled by skeletal muscles, to the automatic internal functions of smooth muscles, to the vital pumping performed by the heart, the human body could not survive without the coordinated work of these three types of muscles.