respiration mechanics Flashcards
what is respiration?
gas exchange and the associated processes
what are the PO2 and PCO2 values at rest?
100+/- 2mmHg
40+/-2 mmHg
how is air filtered?
upper airways to bronchioles lined by pseudo-stratified, ciliated, columnar epithelium, inhaled particles stick to mucus, mucus moved towards mouth by beating cilia
what is the value of ventilation at rest?
~6L/min
how does inspiration occur?
active, diaphragm contracts downwards pushing abdominal contents outwards, external intercostals pull ribs out and up
how does expiration occur?
passive- elastic recoil
how does strenuous inspiration occur?
greater contraction, accessory muscles active
how does strenuous expiration occur?
abdominal muscles, internal intercostal muscles oppose external intercostals by pushing ribs down and inwards
what is the alveolar pressure at the beginning of inspiration?
0, no flow
what happens to the pleural pressure as the muscles contract?
it becomes negative
what happens to the alveolar pressure as the muscles contract?
it also becomes negative as glottis opens and air moves to lung- pressure decreases
when does flow stop and glottis close?
when atmospheric and alveolar pressure are equal
in healthy lungs how much O2 is in each litre of air?
1ml
why is higher intensity breathing less efficient?
gas flow is turbulent, it uses more muscles, accessory muscles can fatigue easily
what is functional residual capacity?
the vol. air in the lung at the end of expiration during quiet breathing
