Principle of Breathing Follows Boyle's Law PVa( At Rest with mouth open Pb=Pi=0 Inhalation. Airway open Pb outside is now greater than Pi Air flows down pressure gradient Until Pi= Pb CW 3
17 CW Follows Boyle’s Law: PV= C At Rest with mouth open Pb = Pi = 0 Inhalation: - Pb outside is now greater than Pi - Air flows down pressure gradient - Until Pi = Pb D Pi A PS Pb Airway Open Principle of Breathing 3
Principle of Breathing Follows Boyle's Law PVa( At Rest with mouth open Pb= Pi=0 Airway Open Exhalation: Opposite Process Decrease Rib Cage Volume cW 18
18 CW Follows Boyle’s Law: PV= C D Pi A PS Pb Airway Open At Rest with mouth open Pb = Pi = 0 Exhalation: Opposite Process - Decrease Rib Cage Volume Principle of Breathing 4
Principle of Breathing Follows Boyle's Law PVa( At Rest with mouth open Pb= Pi=0 Airway Open A Pi Exhalation: Opposite Process Decrease Rib Cage Volume Cw Increase in pleural cavity pressure Increase Pi 5 19
19 CW Follows Boyle’s Law: PV= C At Rest with mouth open Pb = Pi = 0 Exhalation: Opposite Process - Decrease Rib Cage Volume - Increase in pleural cavity pressure - Increase Pi D Pi A PS Pb Airway Open Principle of Breathing 5
Principle of Breathing Follows Boyle's Law PVa( At Rest with mouth open Pb= Pi=0 Airway Open A Exhalation: Opposite Process Decrease Rib Cage Volume cw Increase Pi Pi is greater than Pb Air flows down pressure gradient Until Pi=Pb again
20 CW Follows Boyle’s Law: PV= C At Rest with mouth open Pb = Pi = 0 Exhalation: Opposite Process - Decrease Rib Cage Volume - Increase Pi - Pi is greater than Pb - Air flows down pressure gradient - Until Pi = Pb again D Pi A PS Pb Airway Open Principle of Breathing 6
Mechanisms of Breathing How do we change the volume of the rib cage To Inhale is an ACTIVE process Diaphragm .External Intercostal Muscles Rib Cage Intercostals ime Rib Contract Contract Diapir lgm ume S lume Both actions occur simultaneously -otherwise not effactive
21 Mechanisms of Breathing: How do we change the volume of the rib cage ? To Inhale is an ACTIVE process • Diaphragm Rib Cage Contract Diaphragm Volume •External Intercostal Muscles Intercostals Contract to Lift Rib Spine Ribs Volume Both actions occur simultaneously – otherwise not effective