Muscular system


The muscular system is made up of over 600 muscles, nearly all of them attached directly to the skeletal system at least twice. Myology, the study of muscles, determined that each muscle creates its own individual organs. The muscular system contributes to approximately 40% of the body’s overall weight in an average sized individual. The muscular system is comprised of more than just the muscles, it is also comprised of connective tissue and nervous tissue. The muscular system is responsible for the body’s ability to move. Each muscle is dedicated to its own movement, one muscle for the movement of a finger, one muscle for the movement of the eyelid, and one muscle for the movement of tongue, However, a group of muscles might be responsible for a single body part, such as one muscle may move the leg forward but a different muscle moves the leg back. While each individual muscle has its own dedicated job, it takes the cooperation of muscles to move an entire body part.

Muscle movement occurs when enough muscular impulses direct the muscle to create movement. Muscles have a continuous although unnoticeable current of impulses running through them, although the impulses are far from significant enough to bring about movement. The impulses which direct movement must reach a critical mass for muscles to respond appropriately and create movement within the body. Muscle cells only respond to these impulses.


Muscles are responsible for three basic functions in the body. Muscles create movement, generate heat, and provide basic postural support. The most obvious function, movement, includes everything from the ability to walk to the ability blink. Movement is caused by electrical impulses sent to the specific and necessary muscle, which responds to the stimuli by moving and propels the muscle as directed. Tonus, which is the constant generation of basic currents and stimulus through the body is vital for blood flow throughout the muscle tissue, as well as a mild but continuous form of exercise throughout the muscles even at rest. Tonus is also a contributing component to involuntary muscle movements, such as a heart beat.

Muscles play a significant role in the body’s ability to maintain a constant temperature regardless of the temperature which surrounds it. Metabolism, which is the process of turning food into energy, releases heat, which in turn helps to maintain a regulated body temperature. Muscles, which comprise approximately 40% of the body’s weight, carry enough impact on the human body based solely on their mass to be the prime source of the body’s ability to heat itself and maintain a steady constant temperature. The state of chronic muscle fiber activity maintains body temperature and the state of strenuous muscular activity increases body temperature, encouraging the human body to produce sweat to cool the temperature.
Muscular system
Image: Muscular System

While the skeletal system is responsible for giving the human body a frame, the muscular system then adds to the frame through mechanisms of support. Muscle hold the skeletal system in place while also allowing it the movement necessary to create human posture, motion, and activity from the basic of sitting and standing to the finest intricate motions such as athleticism to the finest motor skill manipulation. Muscle tissue continuously gives the skeletal system this support even at rest. The human body in the sitting position is then using muscle activity to hold the head upright, to balance on the buttocks, and to keep appendages in a place of rest.


Muscles are grouped based upon the anatomical position, their designed function, and their structural design. Facial muscles, neck muscles, and torso muscles anteriorly and posteriorly are part of the axial skeletal muscles while muscles of the pelvic girdle, pectoral girdle, and the muscles of the extremities are grouped with the appendicular skeletal muscles.

There are three basic muscle tissue types in the human body. Smooth muscle tissue, cardiac muscle tissue, and skeletal muscle tissue all vary in their responsibilities, function, and structural components they all share four basic properties.

Irritability refers to the muscles’ ability to respond to stimulus whether the response is basic, such as movement, or severe, such as muscle tearing, damage, or breakdown.

Contractibility refers to the muscles’ ability to respond to stimulus via shortening and contracting lengthwise. Contracting makes the heart pump, the skeletal muscles create movement, and the smooth muscles respond to the body’s basic function needs.

Extensibility refers to the muscles’ ability to be stretched, often beyond their resting position. The natural action of extensibility prepares the muscles for their next contraction. Extensibility performed by outside stimuli prevents the muscles from tearing, bruising, or becoming over stressed.

Elasticity refers to the muscles’ ability to return to their original position, particularly after being exerted or stretched. The muscles’ elasticity maintains their shape, size, and prevents damage.


Muscles are a primarily basic bodily system, providing simplistic and basic movement. However, their complexity is hidden behind their basic design and can be determined in their make up and structural design. While all mammals have muscles, as do most other species, the human muscular system is complex and intricate in both design and function.

Muscles in the human body must be in a chronic cooperative state in order for the human body to function properly. The loss of one muscle can affect surrounding muscles as well as muscles that seem far removed from the affected muscle. However, the muscular system is so intricately connected that one dysfunctional muscle can affect the entire system, especially if it is a muscle which is heavily depended upon for its mobility uses. The muscles that keep the skeleton in place and as a working part of the human body are vital, and their structure provides the basis for the body’s mobility. The muscular system relies on the body’s skeletal system as well as the nervous system in order to maintain function. These systems in conjunction with each other produce the body’s ability to move, to maintain the body’s basic structure and posture, and provide the body with basic functions.
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human anatomy Organs included in Muscular system

Abdominal musclesAxial muscles
Crural musclesFlexion, extension, pronation, and supination of the handHand muscles
Infrahyoid musclesMotion of flexion and extension of the elbow jointMuscles involved in knee motion
Muscles involving facial expressionMuscles involving masticationMuscles involving respiration
Muscles involving the pectoral girdleMuscles of the pelvic outletMuscles of the vertebral column
Muscles of thigh and the hipNeck musclesOcular muscles
Scapular musclesSkeletal muscle fiberSkeletal muscles
Suprahyoid musclesTongue muscles