The human muscular system and their functions

Human muscular system

Get to know the human muscular system

The human muscular system consists of more than 600 muscles in the body. These muscles are made up of special cells known as muscle fibers.

You may think that what is called muscle is only what is visible or appears to be under the skin layer. In fact, apart from the skeletal muscles that appear beneath the skin, there are smooth muscles and heart muscles.

Apart from bones, muscles are also attached to internal organs and blood vessels. Each type of muscle has a specific function, but the main thing is to create movement. In fact, almost every movement in the body is the result of contracting muscles.

Not only movement, muscle contraction also helps regulate posture, joint stability, and body heat production.

Types of muscles

Human muscular system by type

Muscle is one of the four most important tissues in the body. This tissue is made of special cells called fibers. Muscle tissue is divided into three different types.

The types of muscle tissue include:

Smooth muscle (smooth muscle)

Smooth muscle can be found in the walls of internal organs such as blood vessels, digestive tract, respiratory tract, bladder, and uterus. Not only that, smooth muscle can also be found in the eye.

In the organs used to see this, smooth muscle functions to change the size of the iris or iris and change the shape of the eye lens. Smooth muscle in the skin can also cause the hair on the neck to stand up in the face of cold weather or imminent fear.

However, in the human muscular system, the mechanism of action of this smooth muscle is controlled by the automatic nervous system. This means that this muscle can move and be controlled by the subconscious mind of the brain, without the need for you to control it with a conscious mind.

Even if you are not aware of its existence, smooth muscle continues to work in the body. The functions of smooth muscles vary depending on their location and position in the body. For example, the smooth muscle mechanisms of the digestive system, such as alternating contraction and relaxation, help food enter the body when digestion occurs.

The characteristics of smooth muscle are spindle-shaped or have a shaft with one central core. The mechanism of this muscle contraction is to contract slowly and rhythmically.

Heart muscle

In contrast to smooth muscle which can be found in several locations in the body, the heart muscle is only present in the wall of the heart and is controlled by the automatic nervous system.

Cardiac muscle cells have light and dark streaks called striations. The arrangement of protein fibers within the cell causes these light and dark bands. Cardiac muscle cells are elongated cylindrical, with one cell nucleus in the middle.

The contraction of the heart muscle is generally controlled by the subconscious mind, but is quite strong, and has a rhythm. When the heart muscle contracts, blood will be pumped out, while when the heart muscle relaxes, the blood will return to the heart after circulating throughout the body.

Skeletal muscle

Skeletal muscle is part of the muscular system that is closely related to the musculoskeletal system. Skeletal muscle is defined as muscle tissue that is attached to human bones. Skeletal muscle is the only muscle tissue that can be controlled consciously.

In the human muscle system, skeletal muscle is one of the most important because of its location in all parts of the body. The function of the skeletal muscles is to contract to move the parts of the body closer to the bones that are attached to the muscles.

Most of the skeletal muscles are attached to the two bones along the joint, so that the muscles function to move the parts of the bone closer to one another. Skeletal muscles not only function to produce movement, they also stop it.

In addition, skeletal muscles can also prevent excessive movement of bones and joints. The goal is to maintain bone stability and prevent damage to the bone structure itself.

This muscle tissue also helps you to be able to consciously control certain functions in the body, such as chewing and urinating and defecating.

The function of this skeletal muscle is also to protect internal organs, especially those located in the abdominal area, and to help support the weight of these organs.

Skeletal muscle cells are the same as heart muscle cells, which are striated. However, skeletal muscle cells are cylindrical and branched and have many cell nuclei in each of their fibers.

Muscle function

Functions of the human muscular system

Each type of muscle found in the human muscular system has its own function. The following are some of the functions of the muscular system in the body.

Perform body movements

The skeletal muscles are responsible for the movements you make. Skeletal muscles attach to your bones and are partially controlled by the central nervous system (CNS).

Skeletal muscles are used whenever you move. The muscles follow the direction you want them to go, together with the bones and tendons.

Adjust body posture

Skeletal muscles also regulate your posture. Flexibility and strength are the keys to maintaining proper posture. Stiff neck muscles, weak back muscles, or stiff hip muscles can damage your alignment.

Poor posture can affect parts of your body and cause joint pain and weakened muscles.

Maintain balance

Skeletal muscles help protect your spine and help you maintain balance. Within the muscular system there are what are called the core muscles, which include the abdominal muscles, back muscles and pelvic muscles. The stronger your core, the better your balance will be.

Supports human blood circulation

In the human muscular system, the cardiac muscle and smooth muscle, whose presence is unconscious, help the heart beat and blood flow throughout the body. This is usually indicated by the presence of an electrical impulse.

Cardiac muscles are found in the walls of the heart. It is controlled by the autonomic nervous system which is responsible for most body functions. Your blood vessels are made up of smooth muscle, and they are also controlled by the autonomic nervous system.

Helps the breathing process

The diaphragm is the main muscle that works during breathing. When you breathe more heavily, such as when you are exercising, the diaphragm needs help from other muscles, such as the abdominal muscles, neck muscles, and back muscles.

Supports the digestive process

The human muscular system also functions in aiding the digestive process. Yes, when the body digests food, the process is controlled by smooth muscles found in the digestive tract.

Your smooth muscles relax and tighten as food passes through your body during digestion. These muscles also help push food out of your body through bowel movements, or vomiting when sick.

Encourage the baby during labor

Smooth muscle is also found in the uterus. During pregnancy, these muscles enlarge and stretch when the fetus's body is in the uterus. During childbirth, the smooth muscles in the uterus contract and relax to help push the baby through the vagina.

Muscle group

Skeletal muscle groupings

To better understand the skeletal muscle system, you can study it by grouping these muscles as follows:

1. Head and neck muscles

According to the SEER Training Modules of the National Cancer Institute, the skeletal muscle system also includes muscles in the face. This muscle allows humans to show various expressions, ranging from expressions of surprise, disgust, anger, fear, and various other expressions.

Human expression is one of the important elements in non-verbal communication. The skeletal muscles found in the face are included frontalis, orbicularis oris, laris oculi, buccinator, and zygomaticus .

Meanwhile, there are four pairs of skeletal muscles that are in charge of chewing food. These muscles, which are the strongest muscles in the entire body, are connected to your lower jaw. Two of these muscles are temporalis and masseter .

2. Torso muscles

Meanwhile, the muscles of the torso include the muscles that can move the spine, the muscles that make up the abdominal wall, and the muscles that protect the pelvis.

Muscles that are incorporated in the skeletal muscles at the torso are muscle groups erector spinae which is located on the sides of the spine is responsible for helping the body maintain an upright position when standing or sitting.

Then, the muscles that are incorporated in the skeletal muscle system in the next part of the torso are the muscles in the thoracic or chest wall that are involved in the breathing process. This muscle is located in the cavity between the ribs. These muscles contract when you exhale.

3. Upper limb muscles

The skeletal muscle system in the muscles of the upper limb includes muscles that attach the scapula to the chest and move the shoulder blades, which attach the upper armbone to the scapula and move the arm, as well as muscles located in the forearm that move the palms, forearms, and wrist.

The muscles that belong to the upper limb are triceps brachii, biceps brachii, brachialis, and brachioradialis .

4. Lower limb muscles

Meanwhile, the muscles that belong to the skeletal muscles of the lower extremities are the muscles that move the thighs. Then, the gluteus muscles whose main function is to move the hips. However, these muscles extend towards the thigh.

There are also muscles that function to move the legs. For example, the large extensor muscle of the limb (quadriceps femoris) which can straighten the leg at the knee. Then the hamstring muscles, which are the large muscles that extend from the hips to the bottom of the knees, are also part of the skeletal muscle system in the muscles of the lower extremities.

Disorders of the muscular system

Disorders or diseases of the human muscular system

As with the skeletal system and the human joints, there are several disorders or problems of the muscular system that you need to be aware of and be aware of. The following are some disorders, problems, and diseases related to the human muscular system, including:

1. Myalgia

Myalgia or muscle pain is a problem in the muscular system that is quite common. In fact, it could be that everyone has experienced this one condition.

The causes of muscle pain can vary, but generally this condition is caused by muscle injury or overuse of the muscles. In addition, this condition can also be caused by various diseases that are also related to the human muscular system, for example fibromyalgia.

Therefore, it is important to always maintain muscle health so that it is not easy to experience it.

2. Muscle cramps

This problem with the muscular system occurs when the muscles contract strongly enough and suddenly make the muscles tight. This condition, which may last for a few minutes, can be painful.

Generally, muscle cramps occur in the legs. Although it tends to be harmless, when you experience it, you cannot use or move the muscles that are experiencing cramps.

3. Muscular dystrophy

The next muscle system disorder is muscle damage that occurs due to congenital abnormalities that are generally hereditary. This muscular dystrophy is a collection of diseases that attack the muscles.

This condition is caused by a lack of dystrophin protein, which is the protein needed by the body to help muscles function normally.

4. Muscle atrophy

Another health problem that affects the human muscular system is muscle atrophy. Generally, this condition occurs when the muscles shrink due to not being used for too long.

However, several other things may also be the cause of muscle atrophy, such as the aging process, malnutrition, the use of drugs, to other health conditions.

5. Paralysis

This one health problem causes the patient to lose strength and control over some of the muscles in his body. This condition can be concentrated in only one area of ​​the body, for example only on the face, on the legs, or on the hands.

However, it does not rule out that this condition is also experienced in several parts of the body simultaneously. This paralysis can be divided into several types:

• Paresis: partial paralysis, in which the patient can still control some of his muscles.
• Paraplegia: paralysis affecting the muscles in both legs and lower body.
• Quadriplegia: paralysis affecting the muscles in the hands, legs, and sometimes from the neck down.
• Hemiplegia: paralysis that affects the muscles on one side of the body only.