Ventilation Flashcards
What factors must the respiratory muscles overcome during inspiration that hinder thoracic expansion?
the natural elastic recoil of the lung
the resistance to airflow through narrow airways, and the surface tension forces at the liquid/air interface in the lobule all appose thoracic expansion
how is the amount of energy expended kept to a minimum?
it is because of the ease with which the lungs can be stretched (lung compliance). because of this we can inhale 500ml without any noticeable effort, while for example blowing this amount into a balloon would take much more effort
describe airway resistance
as air flows through the bronchial tree resistance to airflow occurs as the gas molecules begin to collide with one another in the increasingly narrow airways.
what is the role of surfactant in reducing the work of breathing?
surfactant aids lung compliance. whenever a liquid and gas come into close contact with each other, surface tension is generated. surfactant reduces the surface tension that occurs when alveoli meet pulmonary capillary blood flow in the lobule, thus reducing the amount of energy required to inflate the alveoli.
what is spirometry?
it is a test of airway function which measure the force and volume of the maximum expiration after full inspiration (forced vital capacity).
what is peak flow/peak expiratory flow rate?
it is a test to measure the extent of airway resistance- an inability to meet a certain value based on age, sex and height could indicate airway resistance
What is work of breathing?
work of breathing is the energy required by the respiratory muscles to overcome factors which hinder res muscles
