Diaphragm is a/an?

Appeared in: UPRVUNL - 2021

Explanation

The diaphragm is a large, dome-shaped muscle that separates the thoracic and abdominal cavities.
It is classified as a skeletal muscle because it is composed of striated muscle fibers.
Although it is a skeletal muscle, its function is largely involuntary, controlled by the autonomic nervous system, but it can also be controlled voluntarily.
It is the primary muscle of inspiration; its contraction increases the volume of the thoracic cavity.

Option A: An artery is a type of blood vessel responsible for transporting blood away from the heart. The diaphragm is a muscle, not a blood vessel.
Option C: A bone cavity is a space within a bone, such as the medullary cavity which contains marrow. The diaphragm is a solid, muscular structure.
Option D: Smooth muscle is found in the walls of hollow internal organs (like the intestines and stomach) and is under involuntary control. The diaphragm is composed of skeletal muscle fibers, which allows for voluntary control (e.g., holding one's breath).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomical classification of the diaphragm as background academic context rather than a clinical decision trigger.
Injury to the phrenic nerve (e.g., from spinal cord injury above C3-C5, trauma, or surgery) can lead to paralysis of the diaphragm, causing significant respiratory distress and often requiring mechanical ventilation.
In patients with respiratory distress, positioning them in a semi-Fowler's or high-Fowler's position uses gravity to help lower the diaphragm, which can ease the work of breathing.
Diaphragmatic breathing exercises are taught to patients with COPD to help strengthen the diaphragm and improve breathing efficiency by encouraging full exhalation and inhalation.

How to Approach the Question

First, identify the key term in the question, which is 'Diaphragm'.
Recall the basic anatomical and physiological definition of the diaphragm. Remember its location (separating chest and abdomen) and primary function (breathing).
Consider the tissue type. The key distinction is between skeletal (voluntary/striated) and smooth (involuntary) muscle. While breathing is automatic, you can consciously control it (hold your breath), which points to skeletal muscle.
Evaluate each option: 'Artery' and 'Bone cavity' are fundamentally different types of structures and can be quickly eliminated. 'Smooth muscle' is a plausible distractor, but the element of voluntary control makes 'Skeletal muscle' the more accurate classification.

Concept Tested & Keywords

QKo16AoxrvVbI_Xqhypyz6

E6 Physiology Ganong 27e Vol 2 Part 3 pp. 84-86, 85-87

E6 Anatomy Applied Ashalatha 4e p. 323-325

Practise the full UPRVUNL - 2021

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