A&P II Notes April 3

A&P II - Anatomy Physiology II Notes Respiratory System cont A difference in pressure between ambient air and the pressure in the lungs is

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Respiratory System cont. A difference in pressure between ambient air and the pressure in the lungs is needed to get air into  the lungs – expanded chest cavity leads to a drop in the pressure in the lungs and allows them to  fill Resistance to the air flow – comes from the diameter of the bronchi and bronchioles, usually wide  enough so there isn’t much resistance, when someone has asthma, bronchitis or a severe allergic  response there is constriction of the air passages because the smooth muscle that lines the passages  contracts o Conditions usually accompanied by an increase in mucous production, which makes it even  more difficult for air to flow through Surfactant – reduces surface tension in the alveoli which prevents alveolar collapse o Surfactant isn’t synthesized until two months before birth, so when the infant is born  prematurely the lungs are not mature enough to function because they have no surfactant Air has to be forced into their lungs (pressure is higher outside of the lungs)
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This note was uploaded on 04/18/2008 for the course BI 132 taught by Professor Halpern during the Spring '07 term at BC.

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A&P II - Anatomy Physiology II Notes Respiratory System cont A difference in pressure between ambient air and the pressure in the lungs is

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