mechanism of breathing Flashcards
(18 cards)
alveolar pressure Palv
inhalation: -ve
exhalation: +ve
pleural pressure Pip
-ve: prevent lung collapse
more -ve during inspiration
transpulmonary pressure
Palv - Pip
if Palv = Pip -> collapse
lung compliance
how easily the lung expand when air rush in
low compliance
more Ptp
strong muscle contraction
more energy is needed
high compliance
pros: efficient breathing
cons: risk of atelectasis
decreased elastic recoil
overdistention
determinants of lung compliance
elasticity
surface tension at the air-water interfaces within the alveoli
lung compliance: elasticity
over elastic: stiff lung
not elastic enough: difficulty with exhalation
lung compliance: surface tension
fluid lining -> water (attractive force between molecules generate surface tension to collapse the alveoli
surfactant
lipid reduce surface tension -> increase lung compliance
neonatal respiratory distress syndrome
patho: surfactant deficiency
airway resistance
diameter increase: rate increase
larger airway
prone to have turbulent flow
branchial airway
total cross sectional area increase -> Raw decrease
implication: asthma
bronchoconstriction
smooth muscle of airway constricts
bronchomotor tone
implication: COPD
mucous plugging of airways
too much mucus
implication: bronchomotor tone
lv of contraction / relaxation of the bronchial smooth muscle
contract due to increased parasympathetic activity, increased histamine concentration
assessment
spirometry
lung vol measurement
