Respiratory Dr. Nene Block 2 Flashcards
What are the parts of the Conducting Zones?
The first 16 generations (bronchi, bronchioles and terminal bronchioles)
What are the parts of the Respiratory Zones?
The last 7 generations (respiratory bronchioles, alveolar ducts and sacs) - the transitional and respiratory zone
Defense Mechanism in the Respiratory System: What will clear large particles from 10 - 15 MCM?
Coughing, sneezing, upper airways trapping
Defense Mechanism in the Respiratory System: What will clear Medium Size particles from 2 - 10 MCM?
Mucociliary transport
Defense Mechanism in the Respiratory System: What will clear Small Size particles less than 2 MCM?
Phagocytosis and macrophages
What is the measurement of Alveolar P?
Decreases to about -1 cmH2O during inspiration
- Rises to about +1 cmH2O during expiration.
What is the measurement of Transpulomary P?
Increases from -5 to -6.5 cmH2O during inspiration
- Returns to pre-inspiratory value at the end of expiration.
What is the measurement of Intrapleural P?
Decreases from -5 to -7.5 cmH2O during inspiration
- Returns to pre-inspiratory value during expiration
More negative intrapleural P during inspiration produces what?
greater transverse stretch through the airways → ↓ airways resistance
What is Surfactant?
It reduces surface tension and increase compliance to decrease work
If Lungs have high compliance…..?
High compliance – lungs are easy to expand
Lungs with low compliance need higher transpulmonary P to expand than lungs with higher compliance
What disease causes increase in compliance?
Emphysema (↓ elastic fibers), age
What is normal compliance?
Normal compliance - 0.2 L/cm H2O (varies with lung volume)
What are the causes of decrease in compliance?
Scar tissue in the lungs (TB, fibrosis)
- Pulmonary edema
- Surfactant deficiency
- Impede lung expansion (i.e., paralysis of intercostal muscles)
What is lung compliance?
Is expressed as a change in the lung volume (V) per unit change in the transpulmonary P (P): V/P
Is the ease with which an organ can be stretched (is reciprocal of elasticity)
What diseases have abnormally high lung compliance (steeper slope) and ↓ tendency of the lungs to collapse?
Obstructive lung diseases
Obstruction disorders will have more air in expiration in the lungs, air trapping, FRC volume is more (the volume after inspiration)
What diseases have abnormally low lung compliance?
Restrictive lung diseases
Restrictive disorders will have less air entry and less air going out
What are the functions of surfactant, balloon picture!
Prevention of emptying of small alveoli into large alveoli
Mechanism that stabilizes alveoli from collapsing:
↓ in the alveolar size → ↑ concentration of surfactant in the liquid lining → additional reduction in the surface tension and a decrease in the intra-alveolar pressure.
Law of Laplace: P =2T/r (P – pressure, T – surface tension, r – radius)
↓ in the radius of the alveolus → ↑ P in the alveolus → empting of the small alveoli into the bigger ones and their collapse (atelectasis)
What factors affect Airway Resistance?
Depends on the tube length, tube radius, & interaction between moving gas molecules
R = 8 η l η – dynamic viscosity π r4 r, l - radius and length of the tube
Turbulent flow increases resistance
Small bronchioles can be occluded by smooth muscle contraction (wall), mucus, or edema of the wall
What control does the ANS have on bronchial smooth muscle tone?
Activation of β2 AR → relaxation of smooth muscle fibers → dilation of the airways → ↓ resistance to air flow
Activation of M-cholino-receptors → contractions of smooth muscles in the bronchioles → ↓ diameter of the airways → ↑ resistance to air flow, which helps in distribution of air flow in the lungs (is blocked by atropine)
What control does the ANS have on bronchial smooth muscle tone?
Activation of β2 AR → relaxation of smooth muscle fibers → dilation of the airways → ↓ resistance to air flow
Activation of M-cholino-receptors → contractions of smooth muscles in the bronchioles → ↓ diameter of the airways → ↑ resistance to air flow, which helps in distribution of air flow in the lungs (is blocked by atropine)
What is Inspiratory Reserve Volume?
The maximum volume of air that can be taken over and above the tidal volume, potential volume at the end of quite inspiration
What is Tidal Volume?
the volume of air entering the lungs during single quite inspiration (is equal to the volume which leaves the lungs during quite expiration): 0.5 L (M/F)
What is Expiratory Reserve Volume?
The maximal volume of air expelled by active expiration after the end of quite expiration, potential volume at the end of quite expiration
What is Inspiratory Capacity?
The maximum volume of gas that can be inspired from the end expiratory position
IC = TV + IRV
What is Residual Volume?
The amount of air remaining in the lungs and air ways after a maximal expiratory effort
What is Vital Capacity?
The maximal volume of air that a person can expire (regardless of time required) after a maximal inspiration
VC = TV + IRV + ERV
What is Functional Residual Capacity?
Normal end expiratory volume
FRC = RV + ERV
What is Total Lung Capacity?
The maximal volume of air in the lungs and airway
TLC = VC + RV
On the Flow Volume Loop, where is the Effort Independent Region?
To the RIGHT of the curve
On the Flow Volume Loop, where is the Expiratory Flow Rate?
To the LEFT of the curve
What is the MOA of the Flow Volume Loop?
Mechanism: dynamic airways compression by expiratory effort limits maximal expiratory air flow
What is Anatomic dead space?
The volume of the conducting system of the airways (is ventilated but doesn’t take part in gas exchange)
Dead space ventilation = dead space volume x RR = 150 mL x 12 = 1.8 L/min
What is Alveolar (functional) dead space?
The volume of alveolar spaces, which are ventilated but not perfused, 0 mL
Alveolar ventilation = (TV – dead space volume) x RR = 350 mL x 12 = 4.2 L/min
What are obstructive disorders and what do they do?
↑ in the airway resistance due to narrowing or occlusion of the airways (i.e., asthma, chronic bronchitis, emphysema (only effect DLCO) – distraction of the lung parenchyma, tumors of the bronchial tree) problems in the interstitial lung
Prolonged expiration, decrease in VC and FVC, Increase in TLC, RV and FRC
What are Restrictive disorders and what do they do?
Restrictive disorders:
Generalized decrease in all lung compliance (i.e., pulmonary fibrosis, silicosis, TB, lung edema; constriction of the chest cage – kyphosis, scoliosis, fibrotic pleurisy) problems in lung expansion
FEV1 is normal or greater than normal
Why does PVR fall as flow increases?
Capillaries that were already open, now distend further.
Capillaries that were formerly closed, now open (recruitment)
What chemical factor controls the resistance of blood flow in the pulmonary circuit?
Hypoxic vasoconstriction
