Questions Derived From BRS Phys Flashcards
Volume of lungs that does not participate in gas exchange
May be greater than anatomic dead space in lung dz w/ ventilation/perfusion defects
Physiologic dead space
The sum of tidal volume and inspiratory reserve volume is
Inspiratory capacity
Alveolar pressure minus intrapleural pressure
Transmural pressure
The major site of airway resistance is?
Medium size bronchi
Parasympathetic stimulation, irritants, and the slow-reacting substance of anaphylaxis (asthma) ______ the airways, _______ the radius, and _______ the resistance to airflow
Constrict
Decrease
Increase
Sympathetic stimulation and sympathetic agonists (isoproterenol) _____ the airways via beta-2 receptors, _______ radius, and _______ resistance to airflow
Dilate
Increase
Decrease
High lung volumes are associated with greater traction on airways and _______ airway resistance
Decreased
______ are associated w/ less traction and increased airway resistance, even to the point of airway collapse
Low lung volumes
Intrapleural pressure can be measured by ?
A balloon cath in the esophagus
Obstructive disease in which expiration is impaired
Characterized by decreased FVC, FEV1, and FEV1/FVC ratio.
Air that should have been expired is not, leading to air trapping, increased FRC
Asthma
Obstructive dz w/ increased lung compliance in which expiration is impaired
Decreased FVC, FEV1, FEV1/FVC ratio.
Increased FRC
Barrel chest
Pink puffers or blue bloaters
Combo of chronic bronchitis and emphysema
COPD
COPD type
Mild hypoxemia, maintained alveolar ventilation
Normocapnia
Primarily emphysema
Pink puffers
COPD type
Severe hypoxemia
Do not maintain alveolar ventilation so they become hypercapneic
Right ventricular failure and systemic edema.
Cyanosis
Blue bloaters
Restrictive dz w/ decreased lung compliance in which inspiration is impaired
Decreased in all lung volumes.
FEV1/FVC may be increased or normal
Fibrosis
Lung diffusing capacity increases during exercise because:
There are more open capillaries and thus more SA for diffusion
For a perfusion-limited process, diffusion of gas can be increased only if the _________ increases
Blood flow
Perfusion-limited exchange is what O2 does in ____________ conditions
Normal
Diffusion limited exchange is what O2 does in
Emphysema, fibrosis, strenuous exercise
In _________, the gas does not equilibriate by the time blood reaches the end of the pulmonary capillary
Diffusion-limited exchange
Hemoglobin increases O2 carrying capacity of blood by
70 fold
Causes sickle cell disease
The alpha subunits are normal and the beta subunits are abnormal
In deoxygenated form, makes sickle shaped rods that deform RBC’s
Hemoglobin S
Right shifts for hemoglobin oxygen associated curve
Increase 2,3-DPG concentration
Increase temperature
Increase in pCO2
Decrease pH
Left shifts on the hemoglobin-O2 dissociation curve
Increased affinity of hemoglobin for O2
CO poisoning
HbF
Decreased pCO2
Increased pH
Decreased temperature
Decreased 2,3 DPG concentration
A normal A-a gradient is
Between 0 and 10 mmHg
The A-a gradient is increased if ?
O2 doesn’t equilibriate between alveolar gas and arterial blood (diffusion defect, V/Q defect, R-L shunt)
And PAO2 is greater than PaO2
Pressures are ____ in pulmonary circulation than in the systemic circulation
Much lower
Resistance is _____ in the pulmonary circulation than in the systemic circulation
Much lower
When a person is supine, blood flow is _____ throughout the lung
Nearly uniform
When a person is standing, blood flow is uneven. It is lowest at the _____ and hight at the ______
Apex
Base
Zone of lung
Blood flow highest
Arterial pressure > venous pressure > alveolar pressure
Zone 3
Zone of lung
Blood flow medium
Arterial pressure > alveolar pressure > venous pressure
Zone 2
Zone of lung
Blood flow low
Alveolar pressure > arterial pressure > venous pressure
Zone 1
In the lungs, hypoxia causes vaso________
Constriction
Hypoxia induced vasoconstriction is the opposite of effect of hypoxia in other organs (most organs, hypoxia —> vasodilation) what effect does this have?
Local vasoconstriction redirects blood from poorly ventilated, hypoxic regions of the lung and towards the well ventilated regions, where the blood can pick up more oxygen
Fetal pulmonary vascular resistance is ______ because of ___________
Very high
Generalized hypoxic vasoconstriction
Right to left shunts always result in ? ?
A decrease in arterial pO2
Left to right shunts do what to arterial pO2?
Do not result in decrease
Ratio of alveolar ventilation (V) to pulmonary blood flow (Q)
V/Q ratio
With normal breathing rate, tidal volume, and cardiac output, the VQ ratio is approximately ____ and arterial pO2 is _______ and arterial pCO2 is _______
0.8
100mmHg
40mmHg
Ventilation and perfusion are both lowest at ____ and highest at _____, but there is more of a difference in perfusion
Apex
Base
V/Q ratio is higher at the ________ of the lung and lower at the ________ of the lung
Apex
Base
Regional differences in pO2 are ______ than regional differences for pCO2
Greater
V/Q ratio in pulmonary embolism
infinite (dead space)
V/Q ratio in airway obstruction
V/Q = 0
Resistance to blood flow decreases as you go to the _______ of the lung
Bottom
Perfusion is _______ in the top and _______ in the lowest part of the lung
Smallest
Greatest
Pulmonary vascular smooth muscle _______ in low pO2
Contracts
How does COPD lead to right heart failure?
People w/ obstructive/restrictive lung dz. alveolar pO2 is low. So overall pO2 is low, causes the entire lung to vasoconstrict (normal response to low pO2) and this increases vascular resistance, making the right heart insufficient.
What accounts for the only marginal increase in pulmonary artery pressure in exercise, with increased cardiac output?
- Recruitment; opening up of previously closed arteries
2. Distention; increase in the radius of the existing blood vessels which decreases resistance
Resistance to blood flow through the alveolar vessels ________ as the alveoli expand because the alveolar vessels are longer and their radii are smaller
Increases
Resistance is ______ to length
Directly proportional
Resistance is ________ to radius to the fourth power
Inversely proportional
Inhibits inspiration, therefore regulating inspiratory volume and respiratory rate.
Inhibitory signals to apneustic center
Pneumotaxic center
What stimuli increases breathing rate in peripheral chemoreceptors, but does not in central chemoreceptors
Decreased oxygen level
The distribution of V/Q ratios is ________ during exercise than when at rest
More even
There is resulting decrease in physiologic dead space
The volume remaining in the lungs after the expiration of a tidal volume
Functional residual capacity
Flow rates from large airways are effort ____
Dependent
Flow rates from small airways are effort _____
Independent
