Pulmonary- Howell Flashcards
the pressure inside the airways and alveoli of the lungs is called …
intrapulmonary (alveolar) pressure
pressure in the pleural cavity is called…
intrapleural pressure
pressure in thoracic cavity is called…
intrathoracic pressure
lung compliance refers to…
the ease with which lungs can be inflated (like a new balloon that is stiff vs an old floppy one… difference in how well they can inflate and push out air
lung compliance is determined by ___ and ____ in the lung, ______ and ______
elastin and collagen fibers in the lung, water content, and surface tension
the vol. of air that moves into and out of the respiratory portion of the lungs (gas exchange) is directly related to….and inversely to….
directly: the pressure difference between the lungs and the atmosphere
inversely: to the resistance that the air encounters as it moves through airways
airway resistance is usually (in healthy person) less or more during inspiration vs expiration?
less during inspiration b/c volume is low, high in expiration when vol starts high
airways are _____ during inspiration and become _____ during expiration. how does this apply to lung disease?
pulled open during insp, narrow during expiration (the –>reason why people with conditions that inc. airway resistance have less difficulty during insp than exp.
airway compression: airflow through collapsible airways in the lungs depends on what two things?
distending airway (intrapulmonary) pressures that hold the airways open and the external (intrapleural or intrathoracic) pressures that surround and compress airways.
airway pressure minus intrathoracic pressure is called….
transpulmonary pressure
for the airflow to occur, the _____ must be greater than ____
distending pressure inside the airways must be greater than compressing pressures outside the airways
lung capacities always include_____ lung volumes
2 or more
two types of dead space
anatomic: contained in the conducting airways
alveolar: contained in the respiratory portion of lung
when alveoli are ventilated but deprived of blood flow, they don’t…. and therefore are considered….
don’t contribute to gas exchange and are therefore considered alveolar dead space.
what is a physiological shunt
a mismatching of ventilation and perfusion, resulting in insufficient vent. to provide O2 needed to oxygenate blood in capillaries
perfusion without vent (aka ___) results in _____
aka shunt, low V/Q ratio (e.g. atelectasis)
vent. without perfusion (aka ____) results in ___
aka dead air space, high V/Q ratio (e.g. with PE)
respiratory center of the brain
neurons in pons and medulla
two groups of neurons in the respiratory center of the brain
- dorsal - primary inspiration: control phrenic nerve (that innervates diaphragm) and drive the 2.(ventral) neurons
- ventral - insp. & expiration: control spinal motor neurons of intercostal and abdominal muscles
dorsal nerves of the resp. center are thought to integrate…
sensory input from lungs and airways into the ventilatory response
3 types of lung receptors and what do they do?
stretch: monitor lung inflation
irritant: protect against damaging effects of toxic inhalants
J : sense lung congestion
two groups of chemoreceptors and what do they do?
- central: sense change in CO2 levels
2. peripheral: sense arterial blood O2 levels
tension pneumothorax occurs when…
intrapleural pressure exceeds atmospheric pressure
spontaneous pneumothorax occurs when …
airfilled bleb or blister on the lung surface ruptures
3 dangerous results of tension pneumothorax
compression atelectasis of unaffected lung, shift in mediastinum, compression of vena cava with impairment of venous return
Dx of pneumothorax can be confirmed by,,,
chest radiograph or CT scan
ANS of pulmonary: PNS and SNS
PNS-(Ach)-> vagus nerve –> bronchoconstriction
SNS- (B2)–> bronchodilation
what “tone” predominates in the airways in terms of ANS stimulation ?
normally, a slightly vagal-mediated bronchoconstrictor tone predominates
ANS: what happens when we exercise?
need for increased airflow, vagal-mediated bronchoconstrictor tone is inhibited and bronchodilator effects of SNS are increased.
two commonly recognized types of emphysema
centriacinar- effects bronchioles in the central part of the resp lobule
panacinar - produces initial involvement of peripheral alveoli and later extends to involve more central bronchioles
those with chronic bronchitis are unable to _____ by increasing breathing effort
maintain normal blood gases
a blood-borne substance lodges in a branch of the pulmonary artery and obstructs the flow.. what is this?
PE
3 physiologic factors that contribute to DVT
- venous stasis (blood flow)
- venous endothelial injury (injury to blood wall)
- hypercoaguability states (blood composition)
acute respiratory distress syndrome may result in a number of conditions, including…
aspiration of gastric contents, drugs/toxins, infections, trauma/shock, etc.
although there are a number of conditions may lead to ARDS…they all produce similar pathologic lung changes including…
diffuse epithelial cell injury w/ increased permeability of alveolar-capillary membrane…protein and fluid leakage…edema, surfactant inactivation, and formation of hyaline membrane that is impervious to gas exchange.
