Lecture 2 & 3- Mechanics of breathing Flashcards
What is the definition of breathing
The bodily function that leads to ventilation of the lungs. (Also known as external respiration)
What is the definition of ventilation
the process of moving gases in (inspiration) and out (expiration) of the lungs
Definition of the ‘Mechanics of breathing’
describes the structural and physiological bases of ventilation
Give three examples of obstructive lung disease
Asthma, COPD, lung cancer
Give three examples of restrictive lung disease
Pulmonary fibrosis, pneumothorax, disorders of thoracic skeleton
Is ΔP dependent on atmospheric pressure or pressure in the alveoli?
Alveoli- Atmospheric pressure remains constant
What do the sternocleidomastoids do?
Elevate the sternum
What do the neck muscles do?
Pull ribcage upwards
What does scalenus major and minor muscles do?
elevate first two ribs and sternum
What do the oblique, transversus and rectus abdominis muscles do?
pull ribcage downwards
What do pectoralis major and latissimus dorsi do?
Pull ribcage outwards (by fixing shoulder girdle)
What nerves is the diaphragm innervated by?
C3,4,5
What is the definition of tidal volume
The volume of air breathed in/out during normal breathing
What is the definition of residual volume
The volume of air left in the lungs after forced expiration
Expiratory reserve volume definition
Maximum amount of air breathed out after normal inspiration
Inspiratory reserve volume definition
maximum amount of air breathed in after normal expiration
Total lung capacity definition
TV+IRV+ERV+RV
Fuctional residual capacity definition
ERV+RV
Vital capacity definition
IRV+TV+ERV
If a patient has an FEV1/FVC ratio of below 0.7
Obstructive- FEV1 reduced largely
How would you distinguish between asthma and COPD
In asthma FEV1 would return to normal after salbutamol (inhaler) as it is reversible
What is the definition of compliance?
Change in lung volume per unit change in intrathoracic pressure- (low compliance needs high pressure for same change in volume)
what type of cells produce surfactant
type II alveolar cells
Is surfactant overproduced or deficient in respiratory distress syndrome
deficient
Define the work of breathing
energy used in inspiration the overcome elastic forces is stored as potential energy which is dissipated in expiration
