PSL301H1 Lecture 14: Respiratory Lecture 2 (14)

• School: UTSG
• Department: Physiology
• Course: PSL301H1
• Professor: French, Gramolini, Richardson, Wong

Document Summary

Lecture 2: respiratory system pulmonary ventilation (577, 580-590) Recall boyle"s law: p1v1 = p2v2: when volume increases, pressure decreases, when volume decreases, pressure increases, for a given amount of gas the pressure exerted depends on how much volume the gas is in. By changing lung volume pressure gradients at rest there is equal pressure and thus no air movement. This makes the air move from inside to outside (higher to lower pressure) Air flows down the pressure gradient: creating pressure gradients between outside and the alveolar, it allows air to moves. Muscles of inspiration: diaphragm the main muscle of breathing, controlled by the phrenic nerve from spinal segments c3, c4, c5. Inserted into the lower ribs and moves downwards as it contracts, forcing the abdominal contents down and forward. Refers to the pressure in the pleural cavity and by convention, always given in relation to atmospheric pressure.