ANP 1105 Chapter 22: Respiratory System Physiology pt 1

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Joanne Savory

Document Summary

Anp1105 a dr. joanne savory and dr. m zeroual. Inspiration: period when air flows into the lungs; expiration: period when gases exit the lungs. Atmospheric pressure (patm): pressure exerted by the air (gases) surrounding the body. Quiet inspiration increase volume of thoracic cavity = decrease pressure of gas inside so air rushes in through trachea (the only opening) > ppul air rushes in from the atmosphere and ends: since patm when pip = ppul, at the same time, intrapleural pressure drops ~-6 mmhg relative to patm. Deep/forced inspiration: during exercise; accessory muscles further increase thoracic volume scalene, sternocleidomastoid, pectoralis minor raise ribs more, erector spinae extend back. Quiet expiration: passive process depending more on elastic recoil of lungs than muscle contraction. As inspiratory muscles relax, the rib cage descends and lungs recoil causing intrapulmonary volume to decrease; the alveoli are compressed and ppul rises to +1 mmhg; since ppul > patm gases flow out of the lung.