Skeletal Muscle -Structure, Functions, Types and Facts
Skeletal muscles constitute one of the three types of muscles found in our body. They form an integral part of the body structure since they are responsible for making all the body parts move to cater to the demands. In simple words, the skeletal muscle structure controls the skeletal functions of motion. Tendons are what attach all the skeletal muscles to the bones of the body.
As the only voluntary muscle in the body, skeletal muscle mass forms 40% of the body weight. In the subsequent sections, we shall discuss all the roles, working, structure, types, as well as characteristics of skeletal muscle in detail.
The Three Types of Muscle
There are three basic types of muscles in our body. Let us examine them to get a clearer view of the skeletal muscle.
All the muscles have a discrete structure to facilitate their respective distinct roles. The succeeding table gives an overview of all three types of muscles.
Three Types of Muscle Tissue
All these three types of muscle tissues work in coordination to facilitate overall body functioning.
What are Skeletal Muscles?
A Skeletal muscle is a voluntary muscle that is attached to the bones through connective tissues called tendons. As a part of the central nervous system, each skeletal muscle tissue is under our control and mainly facilitates body actions.
They are striated and made from flexible muscle fibers to allow agility in movement. They constitute a crucial part of the musculoskeletal system that consists of tendons, ligaments, soft tissues, bones, and muscles. The system is vital as it supports the weight of the body and maintains its structure.
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Characteristics of Skeletal Muscles
Every skeletal muscle tissue has the following characteristics-
Stretchable: The muscles can expand or stretch to a great degree.
Contractility: The muscles are flexible enough to contract.
Excitable: The skeletal muscle tissue is highly responsive to stimuli to facilitate reflex actions.
Elastic: The muscles can stretch to a significant extent and return to their pristine state.
Types of Muscle Tissue in The Skeletal Muscles
There are two fundamental types of skeletal muscles, namely red muscles and white muscles. Each has its distinct function to fulfill. Let us see the characteristics of skeletal muscles:
Red Muscles: Red muscles are red due to the presence of myoglobin, a red pigment that is vital for oxygen supply. They have the following features:
The diameter is small.
More mitochondria, relatively.
Copious amount of blood capillaries.
They can contract for a long time, but slowly.
White Muscles: White muscles are white as they contain negligible myoglobin. They have the following characteristics:
Larger diameter
Lesser Mitochondria
They contract faster but cannot contract long without causing fatigue and pain.
How Does a Skeletal Muscle Function?
Skeletal muscles are responsible for body locomotion primarily. However, they serve a few other important functions:-
One vital skeletal muscle function is the protection of all vital internal organs of the body from injuries or damages. They additionally give structural support to tender internal organs.
The muscles provide a frame to the body and maintain the posture. They also provide a balance to the body.
They also help in controlling the release of bowels and urine.
Lastly, they facilitate the regulation of body temperature by producing heat through movement. For instance, shivering is a response to cold, which facilitates heat
Fun Facts
A few fascinating facts about skeletal muscles, one of the three types of muscle, are:-
There are 600 skeletal muscles in the body.
Gluteus Maximus, the biggest muscle in the body, is the primary facilitator of upward movement on staircases. It is present in the buttocks.
The skeletal muscle mass is 36% more in males as compared to females.
FAQs on Skeletal Muscle
1. What are the Four Main Functions of Skeletal Muscle?
The four primary functions of skeletal muscle are- 1) helps in movement, 2) maintains a proper posture of the body, 3) generates energy and heat for the body, 4) protects inner organs of the body.
2. Why do Skeletal Muscles Called Striated Muscles?
Skeletal muscle appears as alternative black and light bands or stripes under a microscope. Hence, they are synonymous with striated muscles.
3. Name the Muscles Which are also Called Skeletal Muscle.
A few names of skeletal muscle are Biceps brachii, Anconeus, Pronator teres, Palmaris Longus, etc. All of them are parts of human anatomy.
4. What is the structure of the skeletal muscle?
The structure of the skeletal muscle is as follows:
The tendons attach the muscles to the bones.
They have cylindrical muscle fibres called fascicles.
Fascicles are surrounded by different layers of fibres:
Epimysium: Outer layer
Perimysium: Middle layer
Endomysium: Inner layer
Sarcolemma segregates the cytoplasm from the extracellular components.
The following skeletal muscles diagram depicts all the above-mentioned parts and their positions. Additionally, you can see that the blood vessels too surround the cells of the muscle. Moreover, each cell consists of a singular nucleus, myofibril.
5. Explain the difference between cardiac and skeletal muscle?
Unlike the smooth muscle, which are non-striated muscles, cardiac and skeletal muscles are striated muscles. This is the only similarity between the two. They differ in the following ways:
Cardiac Muscles | Skeletal Muscles |
They are involuntary muscles. This implies they are not under the control of the nervous system. Hence, we do not direct their movements consciously. | These are voluntary muscles. This implies we can directly control their movements as they are a part of the central nervous system. |
They are only present in the heart. | They are present around the whole skeletal system. |
They help in the contraction and expansion of the heart to facilitate the pumping of blood. | They hold the body structure and help in the process of locomotion. |
The above table shows how both cardiac and skeletal muscles differ.
