Normal intrapleural pressure at the sta/beginning of inspiration is----- cm of H2O.
High-Yield Explanation
During inspiration, the diaphragm and external intercostal muscles contract, increasing the volume of the thoracic cavity. This causes the intrapleural pressure to become more negative, which increases the transpulmonary pressure, causing the lungs to expand Ref: guyton and hall textbook of medical physiology 12 edition page number:316,317,318