What is the difference between atmospheric and intra pulmonary pressure referred to as?

The difference between atmospheric pressure and intra pulmonary pressure is referred to as the pressure gradient. This term is crucial in understanding how air moves during the process of respiration.

In respiratory physiology, the pressure gradient is essential for airflow into and out of the lungs. When the intra pulmonary pressure (the pressure within the lungs) is lower than atmospheric pressure (the pressure of the air surrounding us), air flows into the lungs. Conversely, when intra pulmonary pressure exceeds atmospheric pressure, air is expelled from the lungs. This difference in pressure facilitates the movement of air, enabling breathing.

The concept of a pressure gradient helps explain not only how air flows during ventilation but also why conditions like pneumothorax disrupt normal breathing by equalizing these pressures, thus eliminating the essential gradient for airflow.