Respiratory Pt.2 Flashcards
What are the four steps of respiration?
- Pulmonary Ventilation
- External Respiration
- Transport of Respiratory Gases
- Internal Respiration
Define pulmonary ventilation.
Air moves in/out of lungs; aka breathing
What is external respiration?
Gas exchange between pulmonary blood & alveoli
What is the definition of atmospheric pressure?
The force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of earth
Why is pressure important in the respiratory system?
Keeps the lungs open and is responsible for the movement of air into and out of the lungs
What is intrapulmonary pressure?
Pressure inside the alveoli; rises and falls with breathing but equalizes to atmospheric pressure
What is intrapleural pressure?
Pressure in the pleural cavity; always less than intrapulmonary pressure
What causes the critical negative intrapleural pressure?
Opposing forces in the thorax: lung recoil and surface tension of alveolar fluid
What is transpulmonary pressure?
Difference between intrapulmonary pressure and intrapleural pressure
What is pneumothorax?
Collapse of a lung due to loss of negative pressure in the pleural cavity
What does Boyle’s Law state?
Pressure varies inversely with its volume
What happens during inspiration?
Air enters lungs due to reduced pressure; diaphragm contracts and thoracic cavity height increases
What occurs during expiration?
Air is pushed out of lungs due to increased pressure
Name the three major factors affecting breathing.
- Resistance
- Surface tension
- Compliance
What is airway resistance?
Resistance due to friction that affects gas flow into alveoli
What is the role of surfactant?
Reduces surface tension in alveoli and helps with breathing
What is lung compliance?
The ability of the lungs to expand and recoil with changes in transpulmonary pressure
What is external respiration?
Exchange of O2 and CO2 across the respiratory membrane
What does Dalton’s Law of Partial Pressure state?
Total pressure exerted by a mixture of gases is the sum of the pressures exerted by each gas
What is Henry’s Law in relation to gas diffusion?
Each gas will dissolve in a liquid in proportion to its partial pressure
How does the composition of alveolar gas differ from atmospheric gas?
Due to gas exchange, humidification, and mixing of gases
What factors influence external respiration?
- Structure of Respiratory Membrane
- Partial pressures of gases
- Ventilation and Perfusion Coupling
What happens during ventilation and perfusion coupling?
Matching of airflow to blood flow for optimal gas exchange
True or False: CO2 is more soluble in plasma than O2.
True
Fill in the blank: The _______ is the exchange of O2 and CO2 across the respiratory membrane.
[external respiration]
