respiration part 2 Flashcards
lung compliance is regulated by what?
- lung elasticity
- surface tension
where does the surface tension of the lungs exist at?
exists at air-water interface in alveoli
surface tension is reduced by _________
surfactants
Define surface tension:
Surface tension is: a measure of the intermolecular attractive forces that stabilize liquid
surface tension forces are strong on ______ side, but weak on ______ side
strong on liquid side
weak on the air side
how do surfactants reduce the surface tension of alveoli?
reduces surface tension by reducing intermolecular forces between water
T/F: Surface tension in alveoli (liquid-lined, air-filled spherical sacs) enhances expansion
FALSE
surface tension RESISTS expansion
you can reduce surface tension by decreasing the _______ of water molecules
density
what regulates surfactant release in the lungs?
regulated by stretch receptors in Type II cells
T/F: Overcoming surface tension is more important than lung elasticity in determining lung compliance
true
a deficiency in surfactant production can cause what condition in infants?
Acute respiratory distress syndrome
what group is at risk for acute respiratory distress syndrome?
pre-mature infants
what are the treatments for acute respiratory distress syndrome?
therapy includes artificial surfactant and mechanical ventilation
slow, deep breaths are a consequence of ___________ resistance
increased
rapid, shallow breathing is caused by ___________ compliance
decreased
Airflow is inversely proportional to ________ _______
airway resistance
what is the primary determinant of airway resistance?
tube radius
besides tube radius, what else can effect airway resistance?
transpulmonary pressure
elasticity of tissue in airways
neural and chemical control of smooth muscles
Asthma is caused by what?
Inappropriate contraction of smooth muscle
how can asthma be treated?
can be treated with glucocorticoid therapy and/or bronchodilators
what is the cause of Emphysema?
alveolar tissues damaged or destroyed, perhaps due to overproductioin of proteolytic enzymes
emphysema is a form of ______
COPD
what causes Chronic bronchitis?
mucus or inflammation impairs airflow
what effect does chronic bronchitis have on breathing patterns?
increased resistance = deeper breathing
Heimlich maneuver dislodges particulate matter in the _______________________
upper respiratory tract
what is tidal volume (TV)?
Volume entering lungs per breath
about 500mL
what is inspiratory reserve volume (IRV)?
max Volume inspired
about 3000 ml
what is the expiratory reserve volume (ERV) of the lungs?
Volume exhaled beyond Tidal Volume (breathing out as much as you can)
about 1500 ml
the _________ is the volume in the lungs after maximum exhalation
residual volume
what is the “vital capacity” of the lungs?
IRV + ERV + TV
5000 ml
what is the “total capacity” of the lungs?
vital capacity + residual volume
6000 ml
what are the characteristics of obstructive lung disease?
decreased FEV1
normal vc
how would restrictive lung disease affect vital capacity (VC) and forced expiratory volume (FEV1)?
restrictive lung disease:
Decreases vc
normal FEV1
what is “Minute ventilation”
tidal V x respiratory rate
what is anatomic dead space? how much does an average person have?
anatomical dead space (~150 ml) is the volume of air that is trapped in the alveoli, and is not exchanged during a respiratory cycle
what is alveolar respiration?
AV = (tidal V – dead space) x respiratory rate
how can you increase alveolar respiration rate?
can increase respiratory rate
can increase tidal volume (more effective than increasing rate)
T/F: alveolar dead space is always greater than zero
true
what is physiological dead space?
The sum of anatomical dead space + alveolar dead space
____________ respiration is the gas exchange between air and blood in lung
external
____________ respiration is the gas exchange between blood and cells (interstitial fluid)
internal
both internal and external respiration occur via ________
diffusion
how do Gases diffuse?
from high to low partial pressure
pressure exerted by gas is proportional to what 2 factors?
temperature & concentration
what is Henry’s Law?
amount of gas dissolved in a liquid is proportional to the partial pressure of that gas in equilibrium with the liquid
Partial pressure vs. concentration of a gas in liquid depends on what?
which gas it is and partial pressure of the gas
temperature
Alveolar PO2 (how much O2 is available to the blood) is determined by:
atmospheric PO2 –
rate of alveolar ventilation –
rate of cellular O2 consumption –
Alveolar gas pressures are altered by the ratio of __________ to ___________
ventilation to metabolism
_____________ occurs when ventilation is decreased relative to metabolism
hypoventilation
_____________ occurs when ventilation increased relative to metabolism
Hyperventilation
what are the effects of hypoventilation on partial pressures?
decrease alveolar PO2
increase alveolar PCO2
what are the effects of hyperventilation on partial pressures?
increase alveolar PO2
decrease alveolar PCO2
T/F: hyperventilation occurs during exercise
False
What happens to alveolar PO2 at high altitudes?
drops significantly
why?- the atmospheric partial pressure of O2 drops
O2 uptake is compromised by what?
compromised by disease and strenuous exercise
perfusion inequalities within the lung can be caused by what 2 disease conditions?
vascularized space with no ventilation
ventilated space with no blood supply
how can local control in the lung respond to the perfusion inequalities?
respond by decreasing airflow in the lung (bronchoconstriction)
respond by decreasing bloodflow in the lung (vasoconstriction)
what is the normal Partial pressure of O2 in the alveoli? what about CO2?
Alveolar PO2 = 105 mm Hg
Alveolar PCO2 = 40 mm Hg
what is the partial pressure of O2 in sea-level air? how about CO2?
PO2 (at sea level) = 160 mm Hg
PCO2 (at sea level) = 0.3 mm Hg
what are the partial pressures of O2 and CO2 as blood ENTERS the lung?
PO2 = 40 mm Hg
PCO2 = 46 mm Hg
what are the partial pressures of O2 and CO2 as blood EXITS the lung?
PO2 = 100 mm Hg
PCO2 = 40 mm Hg
what causes Alveolar dead space?
a mismatch between ventilation and bloodflow
