Respiration II Flashcards
What is compliance
measure of elasticity, change in volume over change in pressure
Describe the effect of low compliance on respiration
more effort to inspire
What is an example of low compliance
pulmonary fibrosis
Describe pulmonary fibrosis
lung parenchyma more rigid
Describe the high compliance
more difficulty expiring - lost of elastic tissue and recoil
What is an example of high compliance
emphysema
What are the two components of elastic recoil in the lung
anatomical component, surface tension
What is the effect of surface tension on alveoli
cause constriction
What has to be overcome in order for lungs to expand
surface tension
Why does surface tension develop
differences in forces on water molecules at air/water interface
How does Laplace’s equation apply to alveoli
larger air sacs have lower pressure than small air sacs
How does air flow through alveoli
smaller into larger - this causes collapse
What does adding detergent to alveoli cause
loss of surface tension
What is the function of surfactant
stop small alveoli collapsing - reduce surface tension
What is surfactant composed of
lipids and proteins
What is the effect of surfactant on alveoli
increases compliance, prevents oedema, slows rate of inflation
How much surfactant do small alveoli have
lots
What is used to measure lung volumes
spirometer
Which volume is difficult to measure in lungs
residual volume
What cannot take part in gas exchange
anatomical dead space
What is the vital capacity
forced inspiration
What does Poiseuille’s Law determine
impact of resistance on flow
What is total lung capacity
vital capacity and residual volume
What factors impact on airway resistance
airway diameter, increased mucus secretion, oedema, airway collapse
What controls bronchial smooth muscle
parasympathetic, sympathetic, humoral factors
What is the effect of histamine on bronchial smooth muscle
constriction
What is the effect of adrenaline on bronchial smooth muscle
dilation
Describe the parasympathetic effect on bronchial smooth muscle
ACh acts on muscarinic receptors - constriction
Describe the sympathetic effect on bronchial smooth muscle
noradrenaline stimulates beta receptors - dilation
