Respiratory Phys Review Flashcards
Describe the chemical control of respiration
metabolic change –> peripheral chemoreceptors–>respiratory center–>spontaneous rhythmic discharge to motor neurons–>respiratory muscles
what is the key cellular layer that adds to resistance to air flow?
smooth muscle layer
what is the most influential factor of the Reynold’s formula in resistance to airflow?
radius to the 4th
please list 4 changes to the respiratory passageways in obstructive disease
- inflammation of bronchial epithelium - bronchitis
- secretion from epithelium - asthma, infection
- constriction of smooth muscle - asthma
- physical blockade - tumors, aspiration FB
what are the 3 main factors of air resistance that can change through either disease state or medications?
bronchiolar size, PNS, SNS
What are the diseases/medications associated with each change?
- bronchiolar size: asthma, bronchitis
- PNS: M3 increased - asthma, muscarinic agonists
- SNS: B2 decreased - epinephrine and albuterol
list 3 types of obstructive lung disease
obstruction of the…
- airway wall
- lung parenchyma
- airway lumen
what consists of the respiratory unit
- respiratory bronchiole
- alveolar ducts
- atria
- alveoli
what makes up the respiratory membrane
- surfactant
- alveolar epi
- epithelial basement membrane
- interstitial space
- capillary basement membrane
- capillary endothelial membrane
what is in the lung interstitium
- connective tissue
- smooth muscle
- lymphatics
- capillaries
- cells - fibroblasts (collagen and elastin)
what is the function of collagen
limits lung distensability
what is the function of elastin
major contributor to elastic recoil of the lung
What factors influence diffusion across the respiratory membrane?
Directly related to…
- partial pressure btwn alveoli and blood
- surface area for gas exchange (atelectasis/tumor)
- solubility
Indirectly related to…
- distance btwn the 2 sides of the membrane
- molecular weight of the molecules
What are some unique features of the visceral pleura?
- microvessels are further away from the surface
- supplied by the bronchial circulation
- no drainage for pleural fluid
what are some unique features of the parietal pleura
- microvessela are closer to the surface
- supplied by the intercostal arteries
- have somata - exit points for pleural fluid, proteins, cells
please list the ways in which you can have increased rate of formation of pleural fluid
- increased pulmonary venous pressure (most common - CHF)
- decrease in microvascular oncotic pressure
- decrease in pressure in the pleural space (atelectasis)
- increase in microvascular permeability
- fluid from the parietal cavity (diaphragm lymph)
please list ways in which you can have decreased rate of clearance of pleural fluid
- systemic venous hypertension
- blockage of clearance
compliance is the inverse of elasticity or recoil
true
lung compliance reflects distensability of the lungs
true
what are the 2 things compliance is determined by
- elastin and collagen
2. elastic forces of surface tension
what are the 4 categories of restrictive lung disease
- lung parenchyma
- pleural space
- neuromuscular, chest wall, obesity
- infection of inflammation of the lungs
list 2 examples of lung parenchymal disorders
- fibrotic interstitial disease
- atelectasis
list 2 examples of pleural space disorders
- pneumothorax
- pleural effusion
list 2 examples of neuromuscular, cw, obesity disorders
neuro: polio, MS, MG, Guillain Barre Syndrome
CW: kyphosis, ankylosing spondylitis, flail chest
which circulation is the largest vascular bed in the entire body?
-pulmonary circulation
what is the function of the bronchial circulation
- 1-2% of CO going to the lungs
- some of it goes to the LA = phys shunt
- majority goes back into the RA for oxygenation
what are some conditions that cause hypoxic vasoconstriction
- airway obstruction
- failure of ventilation
- acute lung damage
- high altitude
What is the alveolar PO2 that would cause hypoxic vasoconstriction
what the normal value of V/Q
0.8
what is dead space and give an example of a disease state that has this
- dead space is ventilation of lungs that are not perfused
- an example is pulmonary embolism
what are the main symptoms of a PE
- hypoxemia 2. CP 3. hypotension (RV failure)
what is a shunt
portion of the CO or blood flow tha tis diverted or rerouted - V/Q = 0
please list 3 types of shunt
- physiologic
- L–>R
- R–>L
describe R –> L shunts
- always hypoxic
- cannot be corrected by increasing O2
describe L–>R shunts
- do not cause hypoxemia
- some causes: PDA, traumatic injury
what is the residual volume
- volume of gas left in the lungs after maximal forced expiration
- determined by muscles of expiration and the inward elastic recoil of the lungs
- cannot be measured by spirometry
where does expiratory reserve volume begin
- at the END of TV
- therefore ERV = FRC - RV
define FRC
- ERV + RV
- this is because you do not typically use your expiratory reserve volume
- represents the balance point btwn inward elastic recoil of the lungs and outward elastic recoil of the cw
what values cannot be measured by spirometry
RV, FRC, TLC
what is TLC determined by?
strength of contraction of the inspiratory muscles and inward recoil of the lungs
What is a normal FEV1/FVC?
0.8
what are the changes to FEV1 and FVC in obstructive disease
Ex: asthma
-both decrease but FEV1 decreases more, therefore ratio is
what are the changes to FEV1 and FVC in restrictive disease
Ex: alveolar fibrosis
- both decrease but FVC decreases more so that ratio either stays the same or increases
- same or more than 0.8
