Skeletal muscles are composed of a large number of :

RRB Staff Nurse Ahmedabad-2015

Applied Anatomy

Easy

Appeared in: RRB Staff Nurse Ahmedabad-2015

Explanation

Skeletal muscles are composed of thousands of individual, elongated cells called muscle fibres.
These muscle fibres are the fundamental structural and functional units responsible for contraction.
Muscle fibres are bundled together into groups called fascicles, which are then bundled to form the entire muscle.
Each muscle fibre contains numerous myofibrils, which are made of the contractile proteins actin and myosin.

Option A: Cartilage is a flexible connective tissue found in joints, the rib cage, and other areas; it provides cushioning and support but is not part of muscle tissue.
Option B: Elastic fibres provide stretch and recoil to tissues like skin, lungs, and arteries. While some are present in the connective tissue of muscle, they do not form the main contractile component.
Option C: Inelastic fibres, primarily collagen, form tendons and ligaments, which attach muscle to bone and bone to bone. They are part of the muscle's connective tissue framework but are not the contractile cells.

Visual 1: Diagram: Hierarchical structure of skeletal muscle, showing the breakdown from the whole muscle to fascicles, muscle fibres, myofibrils, and myofilaments.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Composition of Skeletal Muscle as background academic context rather than a clinical decision trigger.
Understanding muscle fiber composition is crucial for comprehending muscle injuries (strains, tears) and conditions like muscular dystrophy, where fibres degenerate.
What if? If a patient engages in resistance training, the muscle fibres do not typically increase in number (hyperplasia) but increase in size (hypertrophy), leading to muscle growth. This is a key principle in physical therapy and rehabilitation.
Muscle atrophy, the decrease in muscle fibre size due to disuse or nerve damage, is a common concern in immobilized patients, necessitating nursing interventions like passive range-of-motion exercises.

How to Approach the Question

First, identify the core subject of the question: the basic building blocks of skeletal muscle.
Recall the definition of skeletal muscle from anatomy and physiology. It is a type of contractile tissue.
Evaluate the options. 'Muscle fibres' directly relates to the term 'muscle' and is the most logical choice.
Eliminate the other options by identifying them as different tissue types: Cartilage (supportive connective tissue), Elastic fibres (for stretch/recoil), and Inelastic fibres (collagen, for strength in tendons/ligaments).
Confirm that muscle fibres are the correct answer as they are the specialized cells that make up the bulk of skeletal muscle.

Concept Tested & Keywords

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