Myocardium is -

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Explanation

The myocardium is the specialized muscle tissue forming the wall of the heart.
Its contractions are not under conscious control, making it an involuntary muscle.
The autonomic nervous system and the heart's intrinsic electrical system regulate its rhythmic and continuous contractions.
While it appears striated (striped) under a microscope like skeletal muscle, its function is involuntary.

Option A: Voluntary muscles are those under conscious control, such as the muscles used to move limbs. The heart beats automatically without conscious thought.
Option C: This is not a standard physiological classification of muscle tissue. Muscles are categorized as skeletal, cardiac, or smooth.
Option D: This option is incorrect because the myocardium fits into only one category: involuntary muscle.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of muscle tissue, specifically the characteristics of the myocardium (cardiac muscle) as background academic context rather than a clinical decision trigger.
The involuntary nature of the myocardium is fundamental to life, ensuring continuous blood circulation to all organs without conscious effort.
Nurses monitor heart rate and rhythm, which are direct indicators of myocardial function. Abnormalities can signal serious conditions like arrhythmias or heart failure.
What if? - If the myocardium were a voluntary muscle, a person would have to consciously command their heart to beat. This would make sleep, distraction, or unconsciousness fatal, as the heart would stop beating.

How to Approach the Question

First, identify the key term in the question: 'Myocardium'.
Recall the definition and location of the myocardium, which is the muscle tissue of the heart.
Think about the function of the heart. Does it require conscious effort to beat? The answer is no; it beats automatically.
This automatic, non-conscious function defines it as an 'involuntary' muscle.
Evaluate the given options. 'Voluntary muscle' is incorrect. 'Mixed muscle' is not a standard classification. Therefore, 'Involuntary muscle' is the correct choice.

Concept Tested & Keywords

Concept Tested: Classification of muscle tissue, specifically the characteristics of the myocardium (cardiac muscle).
Stem keywords: Myocardium
Lead-in keywords: is

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E6 Physiology Ganong 27e Vol 2 Part 3 p. 78-80

E6 Physiology Essentials Sembulingam 10e Part 1 p. 172-173

Practise the full RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.