Respiratory System Flashcards
What encompasses respiration?
all the body processed that accomplish movement of O2 and Co2 from the tissues to support cell metabolism
Define external respiration
the entire sequence of events in exchange of O2 and CO2 between the environment and tissue cells
Define cellular respiration
intracellular metabolic processes carried out within mitochondria that use O2 and produce CO2
What is the respiratory quotient?
ratio of CO2 produced to O2 consumed
Where is the diaphragm located?
the floor of the thoracic cavity
What organ takes up most of the thoracic cavity?
the lungs
What is the pleural sac?
double walled, closed sac
Where does gas exchange occur in the circulatory system?
alveoli
What cell type makes up most of the alveoli?
type I alveolar cells
What substance is secreted by Type II alveolar cells? What does this substance do?
pulmonary surfactant, facilitates lung expansion
What is the role of alveolar macrophages?
provide defense against inhaled microbes and debris
What are the pores of Kohn and what do they do?
connect adjacent alveoli, providing alternate air route if other airway is blocked
Where are the atmospheric pressures?
760 mm Hg; pressure exerted by the weight of gas in Earth’s atmosphere
Where are the intra-alveolar pressures?
760 mm Hg; pressure within alveoli
Where are the intrapleural pressures?
756 mm Hg; pressure within pleural sac, pressure exerted outside the lungs within the thoracic cavity
What keeps the intrapleural pressure below atmospheric pressure?
lung elasticity which tends to pull them inward, while the plural sac remains in the same place, lowering intrapleural pressure.
What is the transmural pressure gradient and how does it relate to lung function?
difference between intra-alveolar pressure and intrapleural pressure
What happens when the transmural pressure gradient is eliminated due to puncture of the pleural sac? What is this called?
collapsed lung; pneumothorax
What is the gist of Boyle’s law? How does it relate to air flow through the lungs?
At any constant temperature, the pressure of a gas varies inversely with the volume of the container; applies to how air moves into and out of lungs during expansion
What does the compliance of the lungs mean? How would an individual deal with less compliant lungs?
how much effort is required to stretch the lungs; greater transmural pressure and more forceful contraction of inspiratory muscles to expand thoracic cavity more to increase the transmural pressure gradient.
What factors impact the elastic recoil of lungs?
- elastin fibers in lung tissue
- alveolar surface tension in thin film of liquid lining alveoli (most important)
Why does surface tension affect elastic recoil?
- resists increases in surface area (resists expansion of alveoli)
- tends to shrink surface area (shrinks alveoli)
Role of pulmonary surfactant in surface tension
- break up cohesive bonds in the thin film and decrease surface tension
- prevents small alveoli from collapsing their air into larger alveoli
Law of LaPlace
𝑷=𝟐𝑻/𝒓
relates to how inward collapsing pressure in a bubble (P) is related to surface tension (T) and radius (r)
What does a spirometer measure?
changes in lung volume with different respiratory efforts
Do the lungs completely empty during passive expiration? How about after maximal expiration?
No, lungs never empty completely.
Define reserve volume
volume in lungs remaining after maximal expiration
What does tidal volume refer to?
volume exchanged during single breath, normally operating during quiet breathing at around half full