Muscle System


Almost everything that is conceived by our brain finds its expression in the muscular system. You can express an idea by the help of muscles of larynx, tongue and mouth (act of speaking), the muscles of fingers (act of writing) or by the skeletal muscles (act of dancing, running, etc.)

Body muscles help an individual to stand erect, walk, move, bend and pick up objects. They help in breathing, blood circulation and functioning of other internal organs. Muscular system is comprised of a variety of organs and muscular tissues. Each of these organs and muscle tissues has a specific task in the functioning of the body.

A clear and detailed introduction of the muscle system:

Muscular System Composition

The muscular system is composed of various organs, including cardiac muscles, skeletal muscles and smooth muscles. One complete muscle organ consists of muscle fibers, nerve tissue, connective tissue and blood vessels. 40 percent of total human body is composed of muscle tissue, which is formed of approximately 600 muscle organs. Muscle tissue can be divided into four main groups according to the site they are present in the body: muscle organs of the lower limbs, muscle organs of the trunk, muscle organs of the upper limbs and muscle organs of the head and neck region.

Muscle System Functions

Human body cannot function without the muscular system. Almost every nervous impulse transmitted by our brain is expressed as the movement of a muscle. The important functions of the muscular system in the human body are described as follows:

1. Movements

Skeletal muscles help in the voluntary movements of each and every human body part. Active contraction of these muscles occurs at the expense of energy, which creates a force that moves the body parts. To say it differently, muscles can be regarded as motors of body, which convert chemical energy present in food in to mechanical work.

2. Posture and stability

Human skeleton is composed of bones and the joints that are formed between them. Skeletal muscles play a major role in stabilizing human skeleton. They also help in maintaining proper posture of human body. Muscular tissues support the joints that are formed between various bones, giving them stability.

3. Heat production

As already stated, active contraction of muscles requires energy. Hence, muscles use a great amount of body’s total energy. Due to this the body’s metabolic rate is increased, producing a large amount of heat in the body. This feature of muscles holds special importance for individuals living in cold climates.

4. Circulation

Cardiac muscles are responsible for forcing the blood out of the heart and pumping it throughout the human body. The blood is in constant motion by the regular pumping motion of the heart, thereby supplying the nutrients to every tissue of the human body and also removing waste products.

5. Digestion promotion

The organs of the human digestive system such as esophagus, stomach and intestine are lined by the smooth muscles. These muscles contract and aid the digestive system to digest food.

Types of Muscles

As already stated, there are various types of muscles present in the body, each with a specific function and structure. The various types of muscles are described below:

1. Smooth muscles

Smooth muscles are the involuntary muscles that line the various internal organs such as blood vessels, organs of the digestive tract including esophagus, stomach, and intestines and organs of the urinary system including ureters. An individual do not have any control over the functioning and mobility of a smooth muscle; hence its contraction and relaxation cannot be controlled. They usually contract rhythmically on their own, for e.g. rhythmic contractions of the muscles of the digestive tract during digestion and of the uterus during childbirth. Smooth muscles are under the control of autonomic nervous system and are also not attached to bones. Smooth muscles help in pushing the food through the digestive tract and also maintain the flow of blood in the blood vessels.

2. Skeletal muscles

Skeletal muscles are the muscles that cover the human skeleton. They are the muscles that are visible to us and can be felt. They help in holding up the bones of the human skeleton together maintaining a proper posture of the body. Skeletal muscles are the most popular muscles and each one of you must be familiar with them. The contraction and extension of skeletal muscles can be controlled voluntarily, implying that when we think of contracting them, our nervous system transmits an impulse to do so. These muscles are connected to the bones, tendons, and ligaments. They help in the movement of the limbs enabling us to perform functions of walking, sitting, jumping running etc. They also provide strength and support to the body and protect the internal organs. Some of the common large muscle of the human body that you must be familiar with are the pectorals, the abdominals, quadriceps, biceps and the gluteus maximus.

3. Cardiac muscles

According to the Texas Heart Institute, the human heart beats at an average of 72 times every minutes amounting to around 3.5 billion times during your whole lifetime. Our heart is composed of cardiac muscle, which is also an involuntary muscle. Cardiac muscle is one of the strongest of all the 650 muscles present in our body and is present only in the heart. It is responsible for the contraction of the heart that leads to the forceful pumping of blood in the circulatory system.

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