HK 3810 Lecture 11: Respirtory system
11 Aug 2018
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Document Summary
Primary role : bring blood in very close proximity to atmospheric air (gases) for exchange. Trachea (1): cartilage rings adds rigidity so that it doesn"t collapse, smooth muscle, control radius, lined by epi cells and goblet cells, secrete mucous trap foreign objects you breath in. Inspired air is 100% saturated with h2o at this point: air spends enough time in lung to be warmed to 37 deg before reaching alveoli. Flow of air = p1 - p2 / r: resistance, r = 8nl / pi r^4, r proportional 1/r^4, radius primary determinant. Inspire inc radius: pull it, expire dec radius, pushing back, reflexes, protection from foreign particles, bronchiol constriction happens followed by a cough. P1 = atmospheric pressure: 760 mmhg constant. P2 = alveolar pressure (pa: driving force to air flow, what we modify physiologically. Set p1 to 0: p2 has to be neg for flow in, p2 has to be pos for flow out.
