L9&10 - Pulmonary System Flashcards
how is the respiratory system organized for breathing?
organized like a tree, each section branches into smaller sections
what allows bronchioles to alter diameter?
they have a considerable amount of smooth muscle and are controlled by the sympathetic nervous system
describe pulmonary ventilation?
Q= ΔP/R
air flows from area of higher pressure to area of lower pressure which then causes changes in the volume of the lungs
how does Boyle’s Law apply to inhalation?
during inspiration, diaphragm contracts - volume of thorax increases and pressure within it falls allowing air to flow from outside into the lungs
how does Boyle’s Law apply to exhalation?
the inhalation process is reversed aided by the elastic recoil tendency of the lungs, therefore expiration is passive
what is lung compliance?
for a given change in pressure, there is a large change in volume - compliance reduced the work of breathing
give an example of lung over-compliance and under-compliance
over-compliance = emphysema
under-compliance = fibrosis
what is surfactant?
liquid produced by certain alveolar cells and lines the inner surface of the alveoli
when does production of surfactant start?
in utero
what are the 3 functions of surfactant?
- reduces surface tension - high surface tension would allow collapse of alveoli
- helps to keep airways open and therefore increases lung compliance
- presence of surfactant reduces the work of breathing
what is tidal volume?
the volume of air moved in and out of the lungs during a normal breath
what is the formula for minute volume?
TV x RR
what is expiratory reserve volume?
the volume of extra air breathed out after a normal exhalation
what is inspiratory reserve volume?
the volume of extra air breathed in after a normal inhalation
what is forced vital capacity?
strongest exhale over 1 second - recorded on a peak flow meter
