Respiration_physiology_students

Respiration_physiology_students - Respiration: Physiology...

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Unformatted text preview: Respiration: Physiology Three forces involved in breathing 1. Torque: during inspiration, the ribs have been elevated and twisted (at chondral portion). Release of muscular pull (end of inspiration) causes ribs to unwind. The force (torque) generated causes a restoration force (return to neutral rib position). 2. Elasticity: lungs are highly elastic and have been stretched during inhalation due to expansion of the thorax. When inspiratory muscles stop contracting, then lungs want to return to their resting shape and size. 1. Gravity: gravity acts on ribs to pull them downward (during passive exhalation) and works on abdominal viscera with a downward force that helps increase the area for the lungs (during inhalation). www.betterhealth.vic.gov.au Look in image library for respiratory system. health .howstuffworks.com health medical animation breathing http://mcdb.colorado.edu/courses/2115 units/other/ribcage%20movie.mov Animation of rib and diaphragm movements BREATHING Inspiration: Active contraction of diaphragm, intercostals and possibly scalene muscles expands thoracic cavity. Lungs through linkage to thorax, expand too*. Negative press. is created in lungs, thus air rushes in until intra-alveolar pressure = to atmospheric pressure. Exhalation: Muscles of inhalation cease to contract gradually (they exert force during early part of expiration to check recoil of lungs--like releasing brake). The dilated thorax-lung complex generates slightly positive pressure and air is exhaled. Restoring forces provided by abdominal contents under pressure, lung elasticity, and ribs which have been elevated and twisted will "unwind" to provide torque . The e xpira to ry fo rc e s a re pa s s ive o r no nm us c ula r during pa s s ive e xpira tio n.** Lung volumes : 1. Tida l vo lum e : (TV) Vo l. o f a ir inha le d a nd e xha le d during a s ing le e xpira to ry c yc le . Va rie s a c c o rding to :* Adult male: 600cc at rest 1670cc light work 2030cc heavy work Adult female: 450cc at rest. 1. Inspiratory Reserve Vol : (IRV) Quantity of air which can be inhaled beyond that inhaled in a tidal vol. @1500cc- 2500cc 1. Expiratory Reserve Vol : (ERV): amt. of air that can be forcibly exhaled following quiet/passive exhalation @1500cc 4. Residual Vol. : (RV): quantity of air that remains in lungs and airways after max. exhalation--ranges from 1000 to 1500cc in yg. adult males+ Dead air spaces: No matter how deeply we inhale, @150cc of residual vol. is nonfunc. for repiratory purposes--called dead air--remains in dead air spaces...
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Respiration_physiology_students - Respiration: Physiology...

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