Diaphragm is also known as-
**Core Concept**
The diaphragm is a dome-shaped muscle that separates the chest cavity from the abdominal cavity, playing a crucial role in respiratory physiology. It is the primary muscle of inhalation, contracting to increase the volume of the thoracic cavity and draw air into the lungs.
**Why the Correct Answer is Right**
The correct answer is based on the anatomical and physiological functions of the diaphragm. The diaphragm is a muscular sheet with a central tendon, innervated by the phrenic nerve. During inhalation, the diaphragm contracts, causing the central tendon to move downward and increase the volume of the thoracic cavity. This increase in volume leads to a decrease in intrathoracic pressure, allowing air to flow into the lungs.
**Why Each Wrong Option is Incorrect**
**Option A:** The diaphragm is not also known as the "intercostal muscle", as intercostal muscles are smaller muscles between the ribs that assist in inhalation.
**Option B:** The diaphragm is not also known as the "pleura", as the pleura is a thin membrane surrounding the lungs and lining the chest cavity.
**Option C:** The diaphragm is not also known as the "pericardium", as the pericardium is a fibroserous sac surrounding the heart.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the diaphragm is a dome-shaped muscle that can be elevated by the abdominal contents during forced expiration, a phenomenon known as diaphragmatic descent.
**Correct Answer:** C.