Does the diaphragm lie between thoracic and abdominal cavities assist us to breathe?

The diaphragm is a dome-shaped muscle that separates the thoracic cavity (chest) from the abdominal cavity. It plays a crucial role in the process of breathing by contracting and relaxing. Here's how the diaphragm assists us in breathing:

1. Inspiration (Breathing In):

- During inhalation, the diaphragm contracts.

- This contraction causes the diaphragm to move downward, enlarging the thoracic cavity.

- As the thoracic cavity expands, the lungs expand as well due to the lower pressure inside compared to the atmospheric pressure outside.

- Air rushes into the lungs through the nose or mouth, filling the expanded lung space.

2. Expiration (Breathing Out):

- When exhaling, the diaphragm relaxes.

- The relaxation of the diaphragm causes the diaphragm to move upward, reducing the volume of the thoracic cavity.

- As the thoracic cavity decreases in size, the lungs are compressed.

- The air inside the lungs is forced out through the nose or mouth as the lungs recoil.

So, the diaphragm acts like a piston that moves up and down, causing changes in the volume of the thoracic cavity. These changes in volume create pressure differences, resulting in the flow of air into and out of the lungs during breathing.