7. Explain how the diaphragm works to influence inhalation and exhalation. Make reference to volume &pressure.

The diaphragm is a large, dome-shaped muscle located at the base of the chest cavity that plays a crucial role in breathing. Its movement influences the volume and pressure within the lungs, driving inhalation and exhalation.**Inhalation (Inspiration):**1. **Diaphragm Contracts:** When you inhale, the diaphragm contracts. This contraction causes it to flatten and move downwards towards the abdomen.2. **Thoracic Cavity Volume Increases:** The downward movement of the diaphragm increases the volume of the thoracic cavity (the space within the chest).3. **Lung Volume Increases:** As the thoracic cavity expands, the lungs, which are adhered to the inner wall of the chest cavity by the pleural membranes, also expand. This increases the volume within the lungs.4. **Intrapulmonary Pressure Decreases:** According to Boyle's Law, as the volume of a container (in this case, the lungs) increases, the pressure within that container decreases. This decrease in pressure within the lungs, called intrapulmonary pressure, makes it lower than the atmospheric pressure outside the body.5. **Air Flows In:** Because air flows from areas of higher pressure to areas of lower pressure, air rushes into the lungs until the intrapulmonary pressure equalizes with the atmospheric pressure.**Exhalation (Expiration):**1. **Diaphragm Relaxes:** During a normal, relaxed exhalation, the diaphragm relaxes. This allows it to return to its dome-shaped position, moving upwards into the thoracic cavity.2. **Thoracic Cavity Volume Decreases:** The upward movement of the diaphragm decreases the volume of the thoracic cavity.3. **Lung Volume Decreases:** As the thoracic cavity shrinks, the lungs also recoil and decrease in volume.4. **Intrapulmonary Pressure Increases:** The decrease in lung volume increases the pressure within the lungs (intrapulmonary pressure), making it higher than the atmospheric pressure.5. **Air Flows Out:** Air flows out of the lungs, down the pressure gradient, until the intrapulmonary pressure once again equalizes with the atmospheric pressure.In forced exhalation (like during exercise or coughing), other muscles, such as the intercostal muscles between the ribs and abdominal muscles, also contract to further decrease the thoracic cavity volume and force air out more rapidly.