42 Pulmonary Mechanics & Ventilation Flashcards
Performs lateral expansion (bucket-handle movement) and anterior expansion (pump handle movement). Used when active and resting
Diaphragm
Used during exercise or lung disease. Only used when active (i.e. not resting)
External intercostals
Sternocleidomastoid, anterior serrati, and scalenes
Other muscles of respiration
The passive process of expiring air. No muscles are involved under resting conditions
Expiration
During exercise or lung disease, this muscle group plays a role in forcing air out of the lungs
internal intercostal muscles
Used to measure flow and volumes of the lungs. Measures flow, volumes. Volume vs time. Can determine:
Spirometry
Volume of air inspired or expired with each normal breath
Tidal volume
The extra volume of air that can be inspired over and above the normal tidal volume when the person inspires with full force
Inspiratory Reverse volume
The maximum extra volume of air that can be expired by the forceful expiration after the end of a normal tidal expiration
Expiratory reserve volume
The volume of air remaining in the lungs after the most forceful expiration
Residual Volume
Vt + IRV = ?
Inspiratory capacity (IC)
The maximum amount of air that can be expired following a maximal insipration
Vital capacity
IRV + Vt + ERV = ?
Vital capacity
The most effective way to measure Vital capacity. Ask the patient to inspire as much as possible, then expire as quickly as possible.
Forced vital capacity
The volume of air exhaled in the first second of the FVC maneuver
Forced expiratory volume in one second (FEV1)
T/F. • Normal people exhale 90% of their VC in 1 second during a forced expiration
False. Normal people exhale 80% of their VC in 1 second during a forced expiration
The amount of air remaining in the lungs following a normal expiration
Functional residual capacity (FRC)
ERV + RV = ?
Functional residual capacity (FRC)
The amount of air in the lungs at the end of a maximal inspiration
Total lung capacity (TLC)
IRV + Vt + ERV + RV = ?
Total lung capacity (TLC)
Total amount of air moved into and out of respiratory system per minute
Minute ventilation
Vt *(x breaths/min) = ?
Minute ventilation
How much air per minute enters the parts of the respiratory system in which gas exchange takes place
Alveolar ventilation
(VT – dead space) * (x breaths/min) = ?
Alveolar ventilation
The volume of air which is inhaled that does not take part in the gas exchange, either b/c it (1) remains in the conducting airways, or (2) reaches alveoli that are not perfused or are poorly perfused
Dead space
Region of the lung in which pressure is -10 cm H2O (very negative)
Upper
Region of the lung in which pressure is -5 cm H2O
Middle
Region of the lung in which pressure is -2 cm H2O. Ventilation is best here. Gravity and airway size contribute to this
Lower
Portion of the airways which conducts gas to the alveoli (mouth, larynx, trachea, bronchioles, etc)
Anatomical dead space
Alveoli containing air but w/o blood flow in the surrounding capillaries (alveoli that are ventilated, but not perfused)
Alveolar dead space
Total dead space in the lung system (anatomic dead space plus alveolar dead space)
Physiologic dead space
This represents the forces that develop in the wall of the lung as the lung expands. This force always acts to collapse the lung
• As the lung enlarges, ___ increases; as the lungs get smaller, ___ decreases.
Lung recoil
The pressure in the thin film of fluid b/t the lung and the chest wall
Intrapleural pressure (intrahoracic pressure)
T/F. Subatmospheric pressures (-) act as a force to expand the lung, and positive pressure (+) act as a force to collapse the lung
• In normal restful breathing, the intrapleural pressure is always subatmospheric pressure or negative, and thus acts as a force to expand the lung
True
calculated as Pinside - Poutside. Calculated as Pinside - Poutside. Positive values cause distension while negative values cause collapse
Transmural pressure
the change in lung volume divided by the change in the surrounding pressure
Compliance
Compliance is inversely proportional to ___
Elasticity
1/(radius^4)
Airway resistance
T/F. The first and second bronchi in the branching airway system of the lungs represent most of the lungs airway resistance
True
___ nerve stimulation produces bronchoconstriction
Parasympathetic (muscarinic receptors) nerve
T/F. Circulating glucocorticoids produce bronchodilation
False. Circulating catecholamines (dopamine, epinephrine, norepinephrine) produce bronchodilation
These diseases restrict the expansion of the lung parenchyma (the airways are normal)
Restrictive lung disease
Ex: COPD, bronchitis, emphysema. In this type of disease, the parenchyma is damaged and can no longer keep the airways open. The lungs are abnormally large in size. The airways can be restricted in size by hypersecretion as well.
Obstructive lung disease
T/F. Increased radial traction is present in obstructive lung disease
False. Reduced radial traction is rpesent in obstructive lung disease
The degree to which the lung parenchyma is working to keep the airways open (increasing the radius of the airways)
Radial traction
