RESP- Mechanics of Breathing Flashcards
what is airway resistance
change in transpulmonary pressure required to produce a unit flow of gas through the airways of the lung
what affect does a decrease in airway radius have
increased resistance and dramatic decrease in airflow
what is a respiratory condition where the airway is constricted
asthma
what effect does turbulent flow have on airway resistance
airway resistance is increased
in what kind of flow does air travel through the airway
laminar flow until it reaches the bronchi where there is a small amount of turbulent flow
what creates wheezing
a blockage / constricted airway creating turbulent flow
what is the purpose of elastin surrounding alveoli in healthy airways
provides radial traction to splint the bronchioles against positive alveolar pressure - without this (such as in CODP) the bronchioles collapse
define lung compliance
defines the relationship between the level of expansive force applied to the lung and the resulting change in lung volume
what is the relationship between lung compliance and expansion
a greater lung compliance = greater expansion
what is transpulmonary pressure
the level of force acting to expand the lung
how is transpulmonary pressure calculated
alveolar pressure - intrapleural pressure
how is lung compliance calculated
change in volume / change in pressure
on a graph, how is lung compliance expressed
the gradient of a curve - the steeper the curve = greater level of compliance
when a lung is described as having low compliance, what does this mean in terms of ease / difficulty in filling the lung
a decrease lung compliance = more difficult to inflate the lung
what factors affect lung compliance
chest wall mechanics - obesity
alevolar surface tension - NRDS
elastin fibres - fibrosis / COPD
