Human Muscular System

The muscular system consists of different types of muscles that work together to enable the full functioning of the body. It allows the movement of the body, maintains posture, and circulates blood throughout the body. They allow a person to move, speak, and chew. They control heartbeat, breathing, and digestion. Muscles compose a majority of the body and account for 1/3 of its weight. Contractile properties are the primary function of muscle fibers, the specialized cells that comprise the muscular system. The movement of the body is accomplished by muscles attached to internal organs and blood vessels. All movement within the body is caused by the contraction of muscles. The exceptions are some cilia, the flagellum on sperm cells, and the amoeboid movement of white blood cells.

Skeletal muscles are also responsible for the expression of facial expressions, eye movements, and breathing. When joints, bones, and skeletal muscles act simultaneously, the result is movements such as walking and running.

Type of muscle tissues

• Visceral muscle

Visceral muscle is found in the organs like the stomach, intestines, and blood vessels. It is relatively weaker muscle tissue. It makes organs contract so that substances could move through the organ. Because visceral muscle cannot be controlled consciously, therefore it is referred to as involuntary muscle. These muscles have a smooth appearance unlike the banded appearance of cardiac and skeletal muscles. The word “smooth muscle” is often used to describe visceral muscle because of its very smooth and uniform appearance under a microscope. 

 Cardiac muscle

Found solely in the heart. The cardiac muscle is responsible for circulating blood throughout the body. It is an involuntary muscle because one cannot control cardiac muscle tissue consciously. Contraction of cardiac muscle happens as a result of self-stimulation. The heart’s pacemaker is composed of cardiac muscle cells, which stimulate other cardiac muscle cells into contracting.  A consequence of this self-stimulation is that cardiac muscle is considered to be intrinsically controlled or autorhythmic. Under a microscope, cells of cardiac muscle tissue appear striated, that is, they exhibit light and dark bands due to the arrangement of protein fibres within the cell. Striations in the cells of cardiac muscle tissue are caused by the arrangement of protein fibres inside the cell, and they help determine a muscle cell’s strength.

Intercalated disks, which are made up of finger-like projections from two nearby cells, provide a strong connection between the cells of cardiac muscle, which are branched X-shaped or Y-shaped cells. The branched structure of the muscle cell and intercalated disks offer resistance to high blood pressures and the strain of pumping blood throughout a lifetime. These features also help the heartbeat as one unit by allowing electrochemical signals to move freely across the cell.

• Skeletal muscle

Skeletal muscle is the only voluntary muscle tissue in the human body that can be purposefully controlled by the nervous system. Since skeletal muscle can be controlled by the nervous system, it is known as voluntary muscle tissue. Skeletal muscle is necessary for every conscious movement that a person makes. Skeletal muscles are mainly used for contractions and for bringing parts of the body closer to the bones that they are attached to. Because skeletal muscles are usually attached to two bones across a joint, these muscles function to bring parts of those bones closer together. A large number of smaller progenitor cells form long, straight fibers, which are striated, and this makes the skeletal muscle fibers very strong. It is called a skeletal muscle because these muscles are always attached to the skeleton in at least one location. 

• Functions of muscle tissues

• Mobility 

Movement is the major function of the muscular system. Muscles are the only tissue in the body that can contract and move different parts of the body.

• Posture

Muscles often contract to hold the body still to maintain the posture and body position. The muscles responsible for the body’s posture are the strongest of all muscles in the body as they hold up the body throughout the day without becoming tired. Skeletal muscles help to keep the body in the correct position when someone is sitting or standing. 

• Stability 

Muscle tendons along with the joints contribute to joint stability. Muscle tendons in the knee joint and the shoulder joint are important for stabilization. The core muscles are like the abdomen, back, and pelvis, stabilize the body and assist in tasks, such as lifting weights.

• Circulation

The organ that pumps blood throughout the body is the heart which is made up of cardiac muscle tissues. The movement of the heart is beyond conscious control and automatically contracts when stimulated by electrical signals. Smooth muscle in arteries and veins plays another role in blood circulation in the body. These muscles maintain blood pressure and circulation in the event of blood loss or dehydration. These expand to increase blood flow during intense exercise when the body requires more oxygen.

• Temperature regulation 

Due to the high metabolic rate of contracting muscles, our muscles produce a large amount of waste heat. The contraction of many small muscles in the body produces our natural body temperature. When we exert more force than usual, the extra muscle contraction leads to an increase in body temperature, which eventually causes sweating.

Conclusion

Muscles play a role in all functions of the body like heartbeat and breathing, running and jumping, and digestion.  The muscular system is consist of specialized cells referred to as muscle fibers. Their predominant function is contractibility. The movement of the body is accomplished by muscles attached to internal organs and blood vessels. . All movement within the body is caused by the contraction of muscles.. Types of muscle tissues are smooth or visceral muscle tissues, skeletal muscle tissue, cardiac muscle tissue. visceral muscle tissues are relatively weaker concerning others.  The primary job of muscle is the movement of the bones, it also enables the heart to beat and constitute the walls of other important hollow organs. 

Muscles allow them to move, speak, and chew. Muscles compose a majority of the body and account for 1/3 of its weight.  When muscles become damaged, they can impact movement, speech, and much more. so all in all without muscles, humans could not live.