Pulmonary pathophysiology Flashcards
what is the first set of bronchioles that does not have cartilage?
terminal bronchioles
after how many branchings do the alveoli appear?
16th or 17th generation of branching
how does contraction of SMCs relate to air flow resistance?
increase
what bronchioles have the largest resistance?
medium sized bronchioles
what clinical scenarios result from decreased bronchiolar size? what happens to resistance?
asthma
bronchitis
increase
what clinical scenarios result from PNS activation (increased M3 activation)? what happens to resistance?
asthma
muscarinic agonists
increase
what clinical scenarios result from SNS activation? what happens to resistance?
EPI
albuterol
decrease
what is the site of gas exchange?
respiratory membrane
what is the composition of the respiratory membrane?
- layer of fluid lining the alveolus containing surfactant
- alveolar epithelium
- epithelial basement membrane
- interstitial space
- capillary basement membrane
- capillary endothelial membrane
what is the most prominent cell of the lung interstitium?
fibroblasts
what are the factors that affect gas diffusion across the respiratory membrane?
D - diffusion of gas across respiratory membrane
P - partial pressure difference between alveoli and blood
A - surface area
d - thickness
what factor of the gas diffusion equation can be modified clinically?
change in pressure
where does the pleural fluid come from?
systemic capillary
what is the most common cause of pleural effusion?
CHF - increased pulmonary venous hydrostatic pressure from visceral side
decreased microvascular oncotic pressure can cause what condition?
widespread edema - lungs are not spared - pulmonary edema
restrictive pulmonary disorders are the result of what process?
decreased expansion of the lungs due to alterations in the lung parenchyma, pleura, chest wall, or neuromuscular function
definition: lung compliance
extent to which lungs will expand for each unit increase in transpulmonary pressure
lung compliance is a reflection of what lung parameter?
distensibility
how is lung compliance related to elasticity?
inversely related
what are the general categories of restrictive lung disorders?
lung parenchyma disorders
pleural space disorders
neuromuscular, chest wall, obesity disorders
infection or inflammation of the lung
what is the compliance level of the pulmonary vessels?
highly compliant
why is the partial pressure lower when entering the left atrium?
bronchial circulation - physiological shunt
hypoxic pulmonary vasoconstriction is a mechanism for what process?
automatic control of pulmonary blood flow distribution
what is the average normal value of V/Q?
0.8
can residual volume be measured by spirometry?
no
how do obstructive lung diseases appear on flow-volume curves?
golf club
how do upper airway diseases appear on flow-volume curves?
truncated, rhomboidal
how do restrictive lung disease appear on flow-volume curves?
shift right, truncated
what is the FEV1 / FVC ratio? what is its significance?
it is the fraction of vital capacity that can be expired in the first second
can differentiate among lung diseases
what is a normal FEV1 / FVC ratio?
0.8
what is the FEV1 / FVC ratio in obstructive lung diseases? why?
decreased (less than 0.7)
both FVC and FEV1 are decreased, but FEV1 is decreased more than FVC
what is the FEV1 / FVC ratio in restrictive lung diseases? why?
increased
both FVC and FEV1 are decreased, but FEV1 is decreased less than FVC
