Respiratory System
Structure & Function
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Mechanics of breathing
inspiration
Expiration
Diaphragm moves down and intercostal contract to pull rib cage up and out allowing air to get sucked in
Diaphragm moves up and intercostal relax to allow rib cage to move in and force air out
Lung Volumes
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http://www.teachpe.com/anatomy/respiratory_volum
Chemical and Neural Control
Neural Control There are two neural mechanisms that govern respiration -- one for voluntary breathing and one for automatic breathing. The voluntary impulse originates in the cerebral cortex region of the brain and the automatic impulse originates in the medulla oblongata.
Chemical Control There are chemoreceptors in the brain and the heart that sense the amount of oxygen, carbon dioxide and acid present in the body. As a result, they modulate the respiratory rate to compensate for any disruptions in balance of any of these chemicals. Too much carbon dioxide or acidity and too little oxygen cause the respiratory rate to increase and vice versa. Carbon dioxide chemoreceptors are much more sensitive than oxygen chemoreceptors and, thus, exert an effect with smaller changes.