Respiratory Physiology I Flashcards
*Describe the following components of respiration: the conducting zone, the respiratory zone, alveoli, blood vessels, elastic connective tissue, pleural sac
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*Describe the anatomic function that makes the lung ideally suited for gas exchange
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*Describe the relevant pressures for airflow. Identify the forces that generate the negative intrapleural pressure and the implications of air introduced into pleural activity.
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What is the main function of lungs?
GAS EXCHANGE
What are the 4 processes required for optimal gas exchange?
- Ventilation- getting gas to alveoli
- Perfusion- removing gas from the alveoli by the blood
- Diffusion- getting gas across alveolar walls
- Control of breathing- regulating gas exchange
What are the components of airways and how do they change as they go further into lungs?
Airways consist a series of branching tubes that become NARROWER, SHORTER and more NUMEROUS as they penetrate deeper into the lung
Compare and contrasts the conducting zone, respiratory zone.
Conducting zone- contain Trachea, bronchi and terminal bronchioles(0-16); NO Alveoli, NO Gas exchange occurs
Respiratory Zone- contain respiratory bronchioles(transitionary; small amount of alveoli) , alveolar ducts and Alveolar sacs(17-23); contain Alveoli
What part of airways represent anatomical dead space?
Conducting zone (since they have no alveoli, no gas exchange
How many alveoli are present in alveoli, how much of this comprises of surface area?
300 million alveoli in lungs, creating total surface area of 75 m^2
Describe what alveoli are, compared to an alveolus.
Alveoli are small, thin-walled inflatable sacs encircled by pulmonary capillaries
Alveolus- single layer of thin exchange epithelium that is site of Gas exchange.
What is the role of Pores of Kohn?
Pores of Kohn is what allows air to flow between adjacent alveoli
pore of Kohn also allow air pressure throughout lung to to be equalized
Where in the airways is velocity of air flow highest?
Velocity of air flow is highest in trachea (conducting zone) and Lowest in terminal bronchioles
What are the three main types of cells in alveoli?
- Type I alveolar cells: Very thin, allowing Gas exchange
- Type II alveolar cells; Thicker, secrete surfactant to ease lung expansion
- Alveolar macrophage- protect and defend
What is the importance of intrapleural fluid?
Intrapleural sac in lung secretes small fluid that has great cohesiveness to hold opposing pleural layer together and create slippery surface, allow movement of membranes as lungs move.
Describe the different pressures involved in air flow movement
- Atmospheric pressure (P B)=760 mmHg at sea level; Decreases as altitude increases
- Intra-alveolar pressure (P A)- total gas pressure in alveoli of lungs; *will equillibriate with atmospheric pressure
- Intrapleural pressure- (Pip)= 756 mmHg; recoil forces create a vaccum (4); closed cavity
- Transmural pressure (P L)- pressure across the lungs (PA - Pip); Key to INFLATING Lungs.
What are the important factors that hold lungs and thoracic wall together in tight place?
The Intrapleural fluid’s COHESIVENESS and TRANSMURAL pressure (most importantly) hold the lungs and thoracic wall in Tight apposition, even though the lungs are smaller.
Which pressure has a slightly negative pressure and why?
Intrapleural pressure or PLEURAL SPACE has a slightly negative pressure because the chest is pulling out, lungs are pulling in and there is no extra fluid to fill expanded space .
What is Pneumothorax?
Pneumothorax: Air enters pleural cavity, interpleural pressure equalizes with atmospheric pressure, transmural pressure gradient is gone, lungs collapse and thoracic wall springs out.
*Explain how pleural pressure, alveolar pressure, airflow and lung volume change during normal quiet breathing cycle. Describe how differences in pressure between the atmosphere and alveoli can cause air to move in and out of lungs
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*Identify the muscles utilized for breathing and whether the process is active or passive
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