Skeletal Muscle

Introduction

Skeletal muscles account for 30 to 40% of total body mass. They are the muscles that attach to your bones and allow you to conduct a variety of actions and activities. Skeletal muscles are voluntary, which means you can regulate when and how they perform.

In other words, skeletal muscle is a type of muscular tissue that is connected to the bones and helps various areas of the body function. These muscles are also known as voluntary muscles, as they are controlled by the neurological system in the body.

Skeletal Muscle Function

The bodily motions such as typing, breathing, extending the arm, and writing are controlled by Skeletal muscles. The muscles when contract pulls the tendons on the bones and cause movement.

The skeletal muscles support the body’s posture. The gluteal muscle is in charge of maintaining the body’s upright posture. Whereas, the Sartorius muscles in the thighs control body mobility.

Thus, the skeletal muscles safeguard and maintain the internal organs and tissues by protecting them from harm.

These muscles also help to support the body’s entrance and exit locations. For example, Sphincter muscles surround the anus, the mouth, and the urinary tract. These muscles contract, reducing the size of the holes and allowing for easier ingestion, faeces, and urine.

Skeletal muscles also help to control body temperature. The skeletal muscle contraction is responsible for heating the body after rigorous exertion.

Skeletal Muscle: Types

Skeletal muscles are classified into two types: red and white muscles.

1. Red Muscles

Myoglobin is the red pigment found in great concentrations in the human body. Red muscles are caused by this pigment. These muscles have a reduced diameter and a high quantity of mitochondria. Myoglobin stores oxygen, which is then utilised by the mitochondria to produce ATP. Red muscles are densely packed with blood capillaries.

2. White Muscles

Unlike red muscles, white muscles are larger in diameter and contain a tiny quantity of myoglobin. They also have a lower amount of mitochondria.

Skeletal Muscle- Contractile Proteins Definition

Skeletal muscle – contractile proteins is composed of muscular fibres with smaller components known as myofibrils. Each myofibril is further made up of three different types of proteins, such as contractile, regulatory, and structural proteins. Actin (thin filament) and myosin are examples of contractile proteins (thick filament).

Therefore, the Skeletal muscle- contractile proteins definition states that skeletal muscle – contractile proteins contractile proteins mediate the sliding of contractile fibres (contraction) in the cytoskeleton of a cell, as well as in cardiac and skeletal muscle. 

The bundles of actin polymers make contractile fibres in the heart and muscles. These actin polymers glide across each other guided by the actions of the motor protein myosin and they also relate to troponin and titin.

Skeletal Muscle- Contractile Proteins Structure

Tendons are elastic tissues or collagen fibres that connect this muscle to the bones. Tendons are made up of connective tissues. Skeletal muscles are made up of a fascicule, which is a bundle of muscle fibres.These fascicules are cylindrical. These muscle fibres are surrounded by blood arteries and many layers of other tissues.

Sarcolemma reticulum, a kind of plasma membrane, lines each muscle fibre. It encloses sarcoplasm, which contains the endoplasmic reticulum. Myofibrils, which include two key proteins, actin and myosin, make up muscle fibres. Perimysium surrounds the fascicule, while endomysium is the connective tissue that surrounds the muscle fibres.

Skeletal Muscle- Contractile Proteins Classification

As per skeletal muscle- contractile proteins classification, contractile proteins are extensively dispersed in nature. They appear to be present in all living cells, not only motor organs. Lately, they have been isolated or seperated from the brain, liver, thyroid, pancreas, and other organs. Of course, the contractile proteins found in various animal and plant cells are not identical due to variances in environmental circumstances and the unique type of the process in which they engage, but they share the majority of enzymatic and physicochemical features. Thus, as a result, they can be considered as a group known as actomyosin-like proteins.

Further, as per skeletal muscle- contractile proteins classification, the muscle proteins are classified as contractile, regulatory, sarcoplasmic, or extracellular. The contractile proteins actin and myosin are the most crucial. Troponin, tropomyosin, M-protein, beta-actin, gamma-actin, and C-protein are important regulatory proteins.

Conclusion 

As can be seen, much muscle movement is a complex activity involving machinations at a cellular level. And the way each of these elements work together is fascinating to study. 

The muscle system of our body is essential to our existence, and we must take care of it. Since skeletal muscles are a misfortune composed of proteins and most of their functions are also carried out by proteins, we must maintain our protein intake. Along with a balanced diet, exercise should also be an integral part of our routine. Since so much of our daily life activity depends on muscles we must take care of them.