Structure of Skeletal Muscles

In the body, skeletal muscle is a type of muscle tissue that is attached to the bones and plays a role in the function of various organs and structures.

 These muscles are also referred to as voluntary muscles because they are controlled by the nervous system in the body when they contract.

The other two are visceral and cardiac muscles.

The structure of Skeletal Muscle

Tendons, which are elastic tissue or collagen fibres that connect the muscle to the bones, attach this muscle to the bones. 

The connective tissues that make up these tendons are called tendons.

 The fascicule, which is a bundle of muscle fibres, is what makes up the skeletal muscles. 

These fascicules have a cylindrical shape.

A network of blood vessels and a number of layers of other tissues surround and protect these muscle fibres. 

The sarcolemma reticulum is a type of plasma membrane that lines the inside of each muscle fibre. 

It is surrounded by a cytoplasm known as sarcoplasm, which contains the endoplasmic reticulum.

 Myofibrils are the building blocks of muscle fibres, and they contain two important proteins, actin and myosin, which are essential for muscle contraction. 

Muscle fibres are protected from outside influences through the perimysium, which is a connective tissue that surrounds the fasciculus.

The Characteristics of Skeletal Muscle

The following characteristics can be found in skeletal muscles:

Extensibility is defined as the ability of the muscles to contract and expand when they are stretched.

Elasticity is defined as the muscle’s ability to return to its original shape after being stretched or contracted.

Excitability is defined as the ability of a muscle to respond to a stimulus when presented with a stimulus.

In contractility, a muscle’s ability to contract when in contact with a stimulus is defined as follows:

Skeletal Muscles Are Divided Into Several Classes

There are two types of skeletal muscles, which are referred to as red and white muscles, respectively.

Muscles in Red

Myoglobin, a red pigment found in high concentrations in the human body, is responsible for the appearance of red muscles. 

These muscles are smaller in diameter and contain a high number of mitochondria, which makes them more efficient. 

In the myoglobin, oxygen is stored for use by the mitochondria in the synthesis of ATP, which is the energy source for the body. 

A large number of blood capillaries can be found in the red muscles.

Muscles of White Colour

The white muscles, in contrast to the red muscles, are larger in diameter and contain a smaller amount of myoglobin than the red muscles. They also have a lower number of mitochondria than the average person.

Functions

Skeletal Muscle Performs a Variety of Functions

The following are the most important skeletal muscle functions to be aware of:

The skeletal muscles are responsible for movements of the body such as typing, breathing, extending the arm, writing, and other activities.

 The muscles contract, which causes the tendons on the bones to pull on the bones, resulting in movement.

The skeletal muscles are responsible for maintaining the body’s posture. 

In order for the body to maintain its upright posture, the gluteal muscle must be strong. 

The Sartorius muscles, located in the thighs, are responsible for movement of the body.

Structural muscles are responsible for both protecting the internal organs and tissues from injury as well as providing support to these delicate organs and tissues.

These also serve to support the points of entry and exit from the body.

 The sphincter muscles are found in the area around the anus, the mouth, and the urinary system.

 It is through the contraction of these muscles that food is swallowed, defecation occurs, and urination is accomplished more easily.

The skeletal muscles are also responsible for regulating body temperature. The body becomes hot after engaging in strenuous exercise. 

Due to the contraction of skeletal muscles, which results in the conversion of energy into heat.

Smooth Muscles

Smooth muscle is a type of muscle tissue that is used by a variety of systems to apply pressure to organs and vessels, among other things. Despite the fact that it is an involuntary muscle, it does not exhibit cross stripes when examined under a microscope.

One of the most important characteristics of smooth muscle is that it is composed of cells that are narrow and spindle-shaped, with a single nucleus that is located in the middle.

It is believed that smooth muscles are composed of myosin and actin fibres that run through the cells and are supported by a framework of various proteins in which the filaments are organised in an alternate stacked pattern across the cell surface.

Cardiac Muscles

Cardiac Muscle is a muscle that surrounds the heart.

A type of muscle tissue found in the heart, the cardiac muscles are one of three types of muscles that work together to pump blood throughout the body through the circulatory system. They are responsible for performing and bringing about coordinated contractions, which allow the heart to pump blood throughout the body.

The cardiac muscle tissues are responsible for the continuous pumping of the heart that occurs as a result of involuntary movements. 

This is one of the distinguishing characteristics of cardiac muscles that distinguishes it from other muscle tissues that can be controlled by the individual. 

Heart contractions are controlled by specialised cells known as pacemaker cells, which regulate the rate at which the heart beats.

Conclusion

The nervous system sends signals to the specialised cells, instructing them on how to increase or decrease the heart rate in response to the signals. It is possible for the pacemaker cells to transmit signals to the cardiac muscle cells, which causes a wave of contractions in the cardiac muscles, which in turn results in the generation of a heartbeat.

The cardiac muscles are made up of the following components:

Nucleus-Gap junctions are a type of junction between two nuclei.

Desmosomes with intercalated discs.