Respiratory Flashcards
What forms the anatomic dead space? Why is it called this?
“Conducting Airways” generation 1-16, consisting of the trachea, bronchi, and non-respiratory bronchioles. This area holds 150mL (1/3 of normal tidal volume) in volume (30% of the breath) and does not participate in gas exchange, only transports oxygen “bulk movers”
How much volume can the lungs hold? What is the surface area?
4L
82 m^2 (most of this is alveolar space)
What is going on in the respiratory zone/unit? What is it made up of?
Generation 17-23, consists of respiratory bronchioles, alveolar ducts, and alveloar sacs. This is where diffusion occurs, there is little forward movement of air
Type 1 vs. Type 2 alveolar cells?
Type 1: takes up most of the surface area (98%), site for gas exchange and diffusion (type 1 cells’ membranes are fused with capillary endothelium)
Type 2: found in the corners of the alveolus, occupies a small surface area, main function is secreting/synthesizing SURFACTANT
What is the function of surfactant in the lungs?
Surfactant is synthesized by type 2 alveolar cells, it reduces surface tension and can help regenerate alveoli after injury. Surfactant is the reason that the alveoli are never COMPLETELY closed
Moving from trachea to alveoli, what occurs with surface area, pressure gradient, and flow/velocity?
As cross sectional area increases, pressure gradient and velocity of flow decreases so that gas exchange can occur
Flow = Volume / Time
Pressure = Force / Area
What is the function of the upper airway (nose to larynx)?
humidity, warm, and filter
What are the major and accessory muscles of inspiration?
Major is diaphragm, allows for expansion of the lung downwards
Accessory are external intercostals, allowing for anterior and posterior expansion, and the scalenes, picking up the first and second rib, allowing for expansion upwards, and SCM moves sternum forward
What area of the lung is a potential space? What does this mean?
Parietal layer, if air were to go here it would be a pneumothorax
Is exhalation active or passive? What muscles are involved?
Exhalation is PASSIVE
Rectus abdominis, other abdominal muscles, oblique muscles, as well as internal intercostals
How is the work of breathing related to pressure and change in volume?
Work = pressure x change in volume
Restrictive vs. Obstructive lung disease
Restrictive: example is obese, this person has decreased compliance
Obstructive: example is COPD, this person has good compliance
What are collagen and elastin?
Collagen: major structural component of lung that limits lung distensibility
Elastin: major contributor to elastic recoil of the lung
Which 2 forces want to pull lungs to collapse?
alveolar surface tension and lung elasticity
During inspiration and expiration, when is the lowest and highest intrapulmonary pressure reached?
Lowest pressure reached halfway into inspiration
Highest pressure reached halfway into expiration
TLC, VC, RV?
TLC: total lung capacity, total volume that can be in a lung
VC: vital capacity, total exhaled from max inhale to max exhale
RV: residual volume, air remaining/”trapped” in the lung after VC
TLC = VC + RV
FRC, ERV?
FRC: functional residual capacity, volume of air in the lung at the end of exhalation during quiet breathing (resting volume of the lung)
ERV: expiratory reserve volume, volume of air that can be exhaled from resting exhale to max exhale
FRC = ERV + RV
RV:TLC ratio tells us what?
How much air is trapped, normal is 25%
In patients with obstructive diseases, RV increases
In patients with restrictive lung diseases, TLC decreases
What value is effected during preoxygenation?
FRC
Which values are static and measured by spirometry?
Tital volume and vital capacity (VC)
Which values are non-static, measured by a gas dilution technique such as helium spirometer or plethysmography?
TLC (total lung capacity), FRC (functional residual), RV (residual volume)
Boyle’s Law: What is happening during inspiration and expiration?
pressure and volume are inversely proportional
Inspiration: air coming in expands the alveoli, volume increases (inspiration muscles are active), pressure decreases
During expiration, elastic recoil causes volume to decrease, therefore pressure increases
What are examples of expiration becoming active?
Asthma, hyperventilation, playing a wind instrument
What happens to the flow volume loop in restrictive and obstructive lung disease?
Restrictive: smaller area of loop
Obstructive: bottom of the loop is normal (inhale is normal), top of the loop is decreased (exhale abnormal)