Intercalated discs are found in:

PGICH Noida NO-2025

Applied Physiology

Easy

Appeared in: PGICH Noida NO-2025

Explanation

Intercalated discs are a defining feature of cardiac muscle tissue, found exclusively in the heart wall.
These specialized junctions connect individual cardiac muscle cells (cardiomyocytes) end-to-end.
They contain gap junctions, which allow for rapid electrical communication between cells, ensuring the heart contracts as a single, coordinated unit (a functional syncytium).
They also contain desmosomes, which provide strong adhesion to withstand the force of contraction.

Option A: Smooth muscle cells are found in the walls of hollow organs. They are spindle-shaped, non-striated, and lack intercalated discs. While some smooth muscle cells are connected by gap junctions, they do not form the complex structure of an intercalated disc.
Option B: Nerve tissues and glial cells are fundamental components of the nervous system, responsible for transmitting electrochemical signals. They are not a type of muscle tissue and have a completely different structure and function.
Option D: Skeletal muscle cells are long, cylindrical, multinucleated fibers responsible for voluntary movement. Although they are striated like cardiac muscle, they function as individual units and are not connected by intercalated discs.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Histology and characteristics of muscle tissue as background academic context rather than a clinical decision trigger.
The presence of intercalated discs allows the heart to function as a 'functional syncytium,' meaning the cells are so well-connected that they behave as a single unit. This is essential for the coordinated, powerful pumping action required to circulate blood throughout the body.
Certain heart diseases, such as arrhythmogenic cardiomyopathy, involve genetic defects in the proteins that make up the desmosomes within intercalated discs. This can lead to cell separation, fibrosis, and life-threatening arrhythmias.
What if? If intercalated discs lacked gap junctions, the electrical signal for contraction could not spread efficiently from cell to cell. This would result in uncoordinated, chaotic contractions (fibrillation), rendering the heart unable to pump blood effectively, which is a medical emergency.

How to Approach the Question

First, identify the key term in the question: 'Intercalated discs'.
This is a factual recall question testing your knowledge of histology, specifically muscle tissue.
Recall the three main types of muscle tissue: skeletal, smooth, and cardiac. Also, consider the other option, nerve tissue.
Systematically evaluate each option. Nerve tissue is not muscle and can be eliminated.
Associate the unique, defining characteristics with each muscle type. Intercalated discs are a hallmark feature of only one type of muscle.
Remembering that intercalated discs are essential for the heart's coordinated pumping action will directly link them to cardiac muscle.

Concept Tested & Keywords

Qgwvy6R3R6rUKynoXKQGaJ

E6 Physiology Ganong 27e Vol 2 Part 2 p. 149-151

E6 Physiology Guyton 4SAE Part 2A p. 147-149

E6 Anatomy Applied Ashalatha 4e p. 85-87