Mechanics of breathing Flashcards
Breathing
The bodily function that leads to ventilation of the lungs aka = external respiration
Ventilation
The process of moving gases in (inspiration) & out (expiration) of the lungs
Mechanics and breathing
Describes the structural & physiological bases of ventilation
Diseases affecting ventilation = obstructive conditions
Asthma
Chronic obstructive pulmonary disease (COPD
Lung cancer
Diseases affecting ventilation = restrictive conditions
Intrinsic = pulmonary fibrosis Extrinsic = pneumothorax, disorders of the thoracic skeleton
Idiopathic disease
No clue what the cause is
atmospheric pressure aka
barometric pressure
P(B)
barometric pressure = constant
P(A)
alveolar pressure = variable
Inspiration = breathe in
P(B) > P(A)
Expiration = breathe out
P(B) < P(A)
Inspiratory muscles in quiet breathing
diaphragm
external intercostal muscles stabilise rib cage
Inspiratory muscles in increasing effort
diaphragm
external intercostal muscles stabilise rib cage
AND
accessory muscles = neck muscles + shoulder girdle muscles
Expiratory muscles in quiet breathing
elastic recoil of tissues
Expiratory muscles in increasing effort
internal intercostals
abdominal wall muscles
Tidal volume
the volume of air moved in or out of the lungs during normal breathing
Inspiratory reserve volume
volume above tidal volume, after a normal expiration take as deep a breath as possible
Expiratory reserve volume
volume below tidal volume, after a normal inspiration, breathe out as deeply as possible
Residual volume
after maximum expiration, the volume of air remianing in the lungs, cannot be measured by spirometry
Vital capacity = VC
maximal inspiration followed by maximum expiration
Functional residual capacity = dependent on compliance
total volume of air after a normal expiration (expiratory reserve volume + residual volume)
Compliance is defined as …
the change in lung volume per unit change in intrathoracic pressure
