Increase in the size of the muscle of the arm in a weight lifter is an example of

KGMU 2024

Pathology & Genetics

Easy

Appeared in: KGMU 2024

Explanation

Hypertrophy is defined as an increase in the size of individual cells, which leads to an enlargement of the affected tissue or organ.
Skeletal muscle cells (fibers) are considered permanent or stable cells; they have very limited capacity to divide and increase their number.
In response to increased demand, such as the resistance training performed by a weightlifter, these muscle cells adapt by synthesizing more proteins (like actin and myosin) and increasing the number of myofilaments, causing the cells themselves to grow larger.
This increase in cell size, without an increase in cell number, is the classic definition of physiological hypertrophy.

Option A: Hyperplasia is an increase in the number of cells, not their size. Skeletal muscle cells do not typically undergo hyperplasia in response to exercise.
Option C: Metaplasia is a reversible change where one mature cell type is replaced by another. This is not what happens in muscle growth from weightlifting.
Option D: Dysplasia is characterized by disordered and abnormal cell growth, size, shape, and organization. It is a pathological process and often a precursor to cancer, not a physiological adaptation to exercise.

Visual 1: Diagram - A comparison showing a normal muscle fiber next to a hypertrophied muscle fiber, illustrating the increase in diameter and internal components.
Visual 2: Infographic - A table or chart comparing the four main types of cellular adaptation (Hypertrophy, Hyperplasia, Metaplasia, Dysplasia) with clear definitions and visual examples for each.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cellular Adaptations as background academic context rather than a clinical decision trigger.
Understanding cellular adaptations is crucial for nurses to recognize both normal physiological changes and the signs of pathological processes.
While muscle hypertrophy from exercise is beneficial (physiological), hypertrophy of the heart muscle (left ventricular hypertrophy) due to chronic high blood pressure is pathological and a major risk factor for heart failure.
Nurses play a key role in patient education regarding lifestyle modifications, such as managing hypertension to prevent pathological hypertrophy or encouraging exercise to promote physiological hypertrophy.

How to Approach the Question

First, identify the key phrases in the question: 'increase in the size', 'muscle', and 'weight lifter'.
Recall the definitions of the four main types of cellular adaptation provided in the options.
Differentiate between an increase in cell 'size' (hypertrophy) and an increase in cell 'number' (hyperplasia).
Recognize that skeletal muscle is a stable tissue composed of non-dividing cells.
Connect the stimulus (weightlifting) to the cellular response. The increased workload causes the existing muscle cells to grow larger to meet the demand.
Conclude that the increase in muscle size in a weightlifter is a classic example of physiological hypertrophy.

Concept Tested & Keywords

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