Respiratory Physiology Flashcards
Conduction Zone
Conduits to gas exchange, including respiratory structures that do not participate in gas exchange.
Respiratory Zone
Site of gas exchange
How many orders of branching happens in the bronchial tree?
23
How many alveoli do the lungs have?
300 million
Which type of epithelium are alveolar walls made of?
Squamous epithelium
Type I cells
Which cells secrete surfactant?
Type II cuboidal cells
also secrete antimicrobial proteins
Left lung anatomy
Smaller
2 lobes separated by oblique fissure
Right lung anatomy
3 lobes separated by oblique (inferior) and horizontal fissures (superior)
Pleurae
Thin, double layered serosa
Parietal pleura sits on thoracic wall
Visceral pleura on external lung surface
Pleural fluid provides lube and surface tension
What is atmospheric pressure at sea level?
P(atm) 760 mm Hg
Intrapulmoary pressure
AKA intra-alveolar pressure
Fluctuates with breathing
Always eventually equalizes with P(atm)
Intrapleural Pressure
P(ip) Pressure in pleural cavity Fluctuates with breathing Always a negative pressure < Patm and Ppul
Two inward forces promoting lung collapse?
Elastic recoil of lungs
Surface tension of alveolar fluid
Force that enlarges the lungs?
Elasticity of chest wall pulling lungs outward
What happens if P(ip) = P(pul)?
The lungs collapse
P(pul) - P(ip) =?
Transpulmonary Pressure
The greater the transpulmonary pressure, the larger the lungs
Atelectasis
Lung collapse
Lack or air delivery, collapsed alveoli
Pneumothorax
Boyles Law
P1V1 = P2V2
Pressure varies inversely with volume
Factors that influence pulmonary ventilation
Airway resistance
Alveolar surface tension
Lung compliance
Airway resistance
Friction is the major source
Gas flow is inverse to resistance
Where is highest resistance in bronchiole tree?
Medium sized bronchi
Where is the least resistance?
Terminal bronchioles
Which drug reduces airway resistance?
Epinephrine
Lungs with COPD showed __ - __% reduction in the number of terminal bronchioles.
72 - 89%
Surfactant
Detergent-like lipid that discourages alveolar collapse.
Produced by type II cells
Lung compliance
Normally high
Surfactant helps by reducing surface tension
Tidal Volume (TV)
Amount of air inhaled or exhaled with each breath under resting conditions.
Average: 500ml
Inspiratory reserve volume (IRV)
Amount of air that can be forcefully inhaled after a normal tidal volume inhalation.
Male: 3100
Female: 1900
Expiratory reserve volume (ERV)
Amount of air that can be forcefully exhaled after a normal tidal volume exhalation.
Male: 1200
Female: 700
Residual Volume (RV)
Amount of air remaining in the lungs after a forced exhalation
average: 1200
Inspiratory Capacity (IC)
Tidal volume + IRV
Functional residual capacity (FRC)
ERV + RV
Vital Capacity (VC)
TV + IRV + ERV
Total lung capacity (TLC)
Sum of all lung volumes
Average total lung capacity?
Males: 6000
Females: 4200
Average volume of dead space?
150 ml
N2 %
78.6
O2 %
20.9
CO2 %
.04
H2O %
.46
CO2 is ___ times more soluble than O2 in water.
20 times
How long does it take for the partial pressures of O2 in the alveoli and blood vessels to reach equilibrium?
.25 seconds
104 mmHg
CO2 diffuses in equal amounts with ?
Oxygen
Ventilation-Perfusion Coupling
The amount of gas reaching the alveoli and the amount of blood reaching the alveoli must be equal for efficient has exchange.
When alveolar CO2 is high, bronchioles _____.
Dilate
When alveolar CO2 is low, bronchioles ______.
Constrict
Oxygen autoregulates ______ Diameter.
Arteriole
An increase in body temperature shift the curve to the?
Right
Decrease in the pH shifts the curve to the?
Right
Bohr effect
Decreases affinity for O2
In what form is CO2 predominantly transported in the blood?
Bicarbonate ions
Slow shallow breathing causes pH to?
drop
True of false. CO2 is the most powerful factor controlling respiration
true
