Chapter 12 Flashcards
which organ receives the largest blood supply?
alveoli
what is the function of the pores of kohn?
evenly disperse surfactant over respiratory membranes to reduce surface tension for easier alveolar inflation
what are the 2 zones of ventilation?
- conducting zones
2. transitional and respiratory zones
what are the conducting zones? what is its function?
trachea and terminal bronchioles
anatomic dead space
functions in air transport, humidification, warming, particle filtration, vocalization, and immunoglobulin secretion
what are the transitional and respiratory zones? what is its function?
bronchioles, alveolar ducts, and alveoli
functions in gas exchange, surfactant production, molecule activation and inactivation, blood clotting regulation, and endocrine function
what is Fick’s law of diffusion?
the pressure differential between air in lungs and lung-chest wall interface causes lungs to adhere to the chest wall and follow its movement
gas diffuses through a sheet of tissue at a rate…?
directly proportional to tissue area, a diffusion constance, and pressure differential of the gas on each side of the membrane
inversely proportional to tissue thickness
what are the 3 phases of inspiration?
diaphragm contracts and flattens
chest cavity grows causing pressure to slightly decrease below atmospheric pressure
lungs inflate
what are the 2 phases of expiration
sternum and ribs drop
diaphragm rises
how does air move out of the lungs?
natural recoil of stretched lung tissue and relaxation of inspiratory muscles
what is residual lung volume? what is its importance?
air volume remaining in the lungs after forced maximal exhalation
allows uninterrupted exchange of gas between blood and alveoli to prevent fluctuations in blood gases during phases of the breathing cycle
how do you calculate total lung capacity (TLC)?
residual lung volume (RLV) + FVC
what is dynamic lung volume dependent on?
maximum “stroke volume” of the lungs (FVC)
speed of moving a volume of air (breather rate)
determined by lung compliance
what are dynamic lung tests useful for? *
indicates severity of obstructive (air out) and/or restrictive (air in) lung disease
how do you increase inspiratory muscle function and maximum voluntary ventilation?
training ventilatory muscles which improves their strength and endurance
what are the differences in lung functions between males and females?
females have reduced lung size and airway diameter, smaller diffusion surface, and lower static and dynamic lung function measures
what are the 2 perspectives of pulmonary ventilation? *
- volume of air moved into or out of the VE respiratory tract each minute
- air volume that ventilates only alveolar chambers each minute
how do you calculate minute ventilation (Ve)?
VE = breathing rate x tidal volume
what is minute ventilation?
the volume of air breathed each minute
what is anatomic dead space? *
air in each breath that does not enter alveoli and participate in gaseous exchange with blood
what is alveolar ventilation? *
portion of inspired air reaching the alveoli and participating in gas exchange
what is the ventilation-perfusion (V-P) ratio?
the ratio of alveolar ventilation to pulmonary blood flow
what is the average ventilation-perfusion ratio?
0.84 L/min blood flow
what are 2 factors that prevent alveoli from functioning adequately in gas exchange?
- underperfusion of blood
2. inadequate ventilation relative to alveolar surface
what happens to breathing and alveolar ventilation during exercise?
breathing becomes deeper
alveolar ventilation increase from 70% to >85% of exercise minute ventilation
what is hyperventilation? *
decrease in FEO2 (fractioned expiratory O2)
increase in pulmonary ventilation that exceeds to O2 consumption and CO2 elimination needs of metabolism
what is dyspnea?
inordinate shortness of breath or subjective breathing distress
what is the valsalva maneuver? *
closing glottis following a full inspiration while maximally activating expiratory muscles
creates compressive force that increase intrathoracic pressure above atmospheric pressure
stabilizes abdominal and thoracic cavities
what is FEO2?
when you are blowing off more O2 than you need
indicator of changes in thresholds (aerobic)
what happens when you perform the valsalva maneuver? *
reduces return of blood to the heart because increased intrathoracic pressure collapses inferior vena cava that runs through chest cavity
