Human Body

Skeletal Muscle – Structure, Functions, Examples

Skeletal Muscle

The bodies of living organisms contain different types of muscles like the skeletal, smooth, and cardiac muscles. The skeletal muscle refers to the muscle that moves the bones and supports the skeleton due to the movement of living organisms. Students can learn more about skeletal muscle here including its structure, functions, and examples.

Definition of Skeletal Muscle

Skeletal muscle refers to a specialized contractile tissue that exists in animals. Its main function is to move an organism’s body.

Such a muscle comprises a series of bundles of muscle fibers and protective membranes surrounding them. Such an arrangement facilitates skeletal muscle to rapidly contract and release without putting the individual fibers to excessive friction.

skeletal muscle

The attachment of most skeletal muscles to the bone is by bundles of collagen fibers. Furthermore, these collagen fibers are tendons.

These muscles certainly produce all the movements of the body parts. Moreover, skeletal muscles are under voluntary control unlike the smooth muscles and the cardiac muscles. Such muscles are striated in nature and hence are similar to cardiac muscles in this respect.

Structure of Skeletal Muscle

Skeletal muscle comprises of a series of muscle fibers which are made up of muscle cells. Furthermore, these muscles happen to be long and multinucleated in nature.

At the ends of each skeletal muscle, the connection of a muscle to the bone takes place with the help of tendon. This particular tendon connects to the epimysium or skeletal muscle’s collagenous outer covering in a direct manner.

Underneath the epimysium, the grouping of the muscle fibers into the fasciles bundles takes place. A collagen protective covering surrounds these fascicles bundles. Furthermore, the primysium allows the nerve and blood vessels to make their way through the muscle.

The formation of each fascicle takes place from tens to hundreds of bundled muscle fibers. The formation of each muscle fiber is from a chain of multinucleated muscle cells.

Moreover, the fibers are protected by another layer known as the endomysium as their bundling takes place into fascicles.

Furthermore, each muscle cell certainly consists of distinct regions when an individual views it from a microscope. These distinctive regions are called sarcomeres.

The formation of sarcomeres takes place from actin, myosin, and other helper proteins. The filaments which one can see between the dark bands are certainly actin and myosin filaments.

Moreover, a number of proteins that accompany actin, help stabilize it and gives it a pathway for muscle contraction.

The Function of Skeletal Muscle

When an individual moves his arm, then the brain sends a nervous signal through the nerves. This simple act of raising the arms certainly needs many muscles.

Therefore, the brain sends the signal down many nerves to many muscles. Moreover, the skeletal muscle receives the nervous impulse at the neuromuscular junctions. Also, there are places where the nerves can stimulate an impulse in a particular muscle cell.

The transverse tubules carry the nervous impulse inside the cell. Furthermore, the impulse releases calcium ions active troponin so as to release from tropomyosin.

The tropomyosin then shifts position so as to allow the myosin heads to attach to the filament. Once the attachment of the myosin heads is completed, the ATP available is used so as to contract the filament.

The accomplishment of this takes place by each pair of myosin heads when they slowly crawl down the filament. The energy from ATP moves one head, while the other is attached.

Consequently, when the nervous impulse hits each muscle fiber and the muscle at the same time, the individual is able to lift the arm in a fluid motion.

Examples of Skeletal Muscle

Below are the examples of the skeletal muscle:

Arms and Legs- The muscles which belong to the arms and legs do their work in pairs.

Abdomen and Back- These muscles refer to the various sets of skeletal muscles that run along the torso. Moreover, this is for both the front and the back.

Head- The skeletal muscles of this region makes up the head and neck. These muscles can help in the movement of eyelids, speaking, eating turning head, etc.

Solved Question for You

Q1 Which of these is not an example of skeletal muscles?

A. Groin region
B. Arms and legs
C. Abdomen
D. Head

A1 The correct option is A., ‘groin region.’ This is because groin region muscles do not fall under skeletal muscles.

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