Flashcards in Section 5 Lecture 3 Deck (72):
True or False? Inspiration is active at all lungs volumes.
F. not for FRC
When does expiration because active?
exercise, cough, vomiting, ling disease that increases airway resistance, speaking and singing
True or False? The more a muscle stretches the more force it can generate.
F. more stretch = less force
What results if the recoil > chest wall force?
What results if the muscles of contraction are weak/
FRC decreases (why? I would think it would increase)
an instrument for measuring changes in volume in lungs:
What can lead to premature airway closure?
plethysmograph > helium (?)
Transpulmonary pressure is aka:
Transpulmonary pressure =
alveolar - pleural pressures
P (w) is:
Transmural pressure across the chest wall
P (w) =
pleural - barometric pressure
P (rs) (respiratory system) =
transmural pressure surrounding lungs + transmural pressure across chest wall OR alvelor - barometric pressure
What does a spirometer tracing show?
lung volumes and capacities
residual volume + ERV
Vital capacity =
ERV + Tidal volume + IRV
Inspiratory capacity =
Tidal volume + IRV
Avg tidal volume:
Avg vital capacity:
Pulmonary volumes, men vs. women:
5800 vs. 4200 (the graph was for a man)
Primary determinants of lung volume:
sex, age, height (20% variability)
Avg RV/ TLC ratio:
Elevated RV/ TLC ratio secondary to RV elevation:
obstructive pulmonary diseases (chronic bronchitis)
Elevated RV/ TLC ratio secondary to TLC decrease:
restrictive lung diseases (pulmonary fibrosis)
Factors affecting the RV/ TLC ration:
elastic recoil of lung, compliance, muscle strength of inspiratory muscles, recoil of the chest wall
How is FRC affected if the chest wall muscles are weak?
FRC decreases, lung elastic recoil > chest wall muscle force
How is FRC affected if there is an airway obstruction?
FRC increases (premature airway closure)
How are measurements of RV and TLC taken?
body plethysmography or helium dilution
C(1) X V(1) =
C(2) X (V(1) + V(2)
P(1) (this is pressure before inspiration) X V (V is FRC) =
P(2) (V - delta v) (P(2) is pressure after inspiration)
True or False? Less than half of the FVC is exhaled during FEV(1).
F More than half, about 3/4
Average FEV1/FVC ratio:
3L/4L = 75%
What factors decrease FEV(1) /FVC ratio?
decrease muscle strength, increases airways resistance, increases lungs compliance
What causes the increase in resistance in emphysema?
smooth muscle constriction and mucus plugging of the airways
Which lungs volumes increases and which decrease in emphysema?
increase: V, FRC, and TLC, decrease: VC and FEV
FEV(1)/FVC ratio in patient with emphysema
How are FEV and FVC related?
FEV = 1/ FVC
Peek expiratory flow rate occurs around how many liters of air expired?
What % of VC is expired at the peek expiratory flow rate?
True or False? Recoil of the lungs increases in inspiration.
FEF from 15-75% is called:
Mid maximal expiratory flow (MMEF)
How will increasing R affect the FEF?
decrease (R = resistance?)
Lungs compliance =
delta V/ delta P
Compliance must be corrected for:
changes in lungs volume
Diseases that cause a reduction in compliance:
emphysema, obstructive pulmonary fibrosis or restrictive diseases
What kind of flow occurs in the small airways?
Velocity in airways =
delta P/V =
Are the small airways in parallel or series?
Factors contributing to airway resistance:
resistance decreases with lung volume, conductance, density of inspired gas, neural control of airway, irritants, and agents
How is the density of inspired gas affected by pressure?
increases pressure, increases density
True or False? Lung volume resistance increases as lung volume decreases.
F. resistance decreases as lung volume decreases
Stimulation of what increases resistance due to airway constriction via smooth muscle?
efferent vagal nerves
List agents that can contribute to airway resistance:
histamine, acetylocholine, throboane A(2), prostoglandin F(2), and leukotrienes due to allergens and viral infections
Effect of the postganglionic neurotransmitter Norepinephrine on airway resistance:
inhibits constriction, stimulation of sympathetic
Maximum inspiratory flow is __ dependent.
effort (1/2 TLC and RV)
Does force increase or decrease with lung volume?
Does recoil pressure increase or decrease with lung volume?
Does resistance increase or decrease with lung volume?
True or False? Expiratory flow resistance is effort-dependent.
When does compression of the airways occur?
P outside > P inside
Crackles are caused by:
the "popping open" of small airways and alveoli collapsed by fluid, exudate, or lack of aeration during expiration.
what are the inherent mechanical properties of the lung?
elastic and flow resistance forces
non elastic resistance
non elastic resistance during inspiration
non elastic resistance during expiration
What % of total body O2 gas flow does the body normally require?