Skeletal muscles are composed of a large number of?

RRB Staff Nurse Mumbai-2015

Applied Anatomy

Medium

Appeared in: RRB Staff Nurse Mumbai-2015

Explanation

Skeletal muscles contain a large amount of connective tissue that provides structure and transmits force.
This connective tissue is primarily composed of collagen fibers.
A defining characteristic of collagen fibers is their high tensile strength and low elasticity; they are strong but do not stretch easily.
Therefore, the term 'inelastic fibres' is an accurate description of the most abundant type of fiber in the non-contractile part of skeletal muscle.

Option A: Cartilage is a specialized, flexible connective tissue found in areas like joints, the nose, and ears. It is not a component of the main body of a skeletal muscle.
Option B: While some elastic fibers are present in the connective tissue sheaths of muscle to allow for recoil, they are significantly less numerous than collagen fibers.
Option D: 'Dense Fibres' is not a standard anatomical term. While the collagen fibers are found in 'dense connective tissue', the term itself is ambiguous. 'Inelastic fibres' is a more precise description of the functional property of the fibers themselves.

Visual 1: Diagram - A cross-section of a skeletal muscle, clearly labeling the epimysium, perimysium, endomysium, and fascicles. This helps visualize the extensive network of connective tissue.
Visual 2: Micrograph - An electron micrograph showing the parallel arrangement of collagen fibers in a tendon, illustrating their dense and inelastic nature.

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 the inelastic nature of tendons is crucial for nurses when dealing with musculoskeletal injuries. A 'pulled' muscle or tendon tear (strain/sprain) occurs when these inelastic structures are stretched beyond their capacity, leading to damage.
In conditions like muscular dystrophy, the connective tissue can proliferate and replace muscle fibers (fibrosis), leading to muscle weakness and stiffness. This highlights the importance of the balance between muscle and connective tissue.
What if? - If skeletal muscle tendons were composed primarily of elastic fibers instead of inelastic collagen, they would stretch like rubber bands. This would make movement inefficient, as much of the force generated by muscle contraction would be lost in stretching the tendon rather than moving the bone.

How to Approach the Question

First, identify the core of the question: it asks about a major component of skeletal muscle.
Recall the basic structure of a skeletal muscle: it's not just muscle cells (fibers) but also includes extensive connective tissue wrappings and tendons.
Evaluate each option based on your knowledge of histology. Eliminate 'Cartilage' immediately as it's a different tissue type.
Compare the remaining fiber types. You know muscle needs both strength and some elasticity. The strength comes from collagen, and elasticity from elastic fibers.
Consider the relative amounts. The primary role of the connective tissue framework and tendons is to provide strength and transmit force, which requires a large number of strong, non-stretchy fibers.
'Inelastic fibres' is a direct description of collagen. 'Elastic fibres' are present but in smaller numbers. 'Dense fibres' is ambiguous; it likely refers to the dense packing of fibers, but 'inelastic' is a more direct property of the fiber itself. Choose the most precise and accurate description, which is 'Inelastic fibres'.

Concept Tested & Keywords

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