Lecture 19: Intro to Respiratory Function Flashcards
Purpose of respiratory system
delivery of O2 from the air to tissue and the removal of CO2 from tissues
also
- regulates pH
- vocalization
- defense against airborne pathogens
respiratory system activity responds to changes in ______ activity
metabolic
gas exchange occurs via simple _____
diffusion
-no proteins or ATP required
Factors in Fick’s Law of Diffusion
- diffusion coefficient
- area over which gas diffuses
-partial pressures of gas inside and out
-distance gas has to diffuse
what purpose does a high surface area serve in respiratory surfaces
greater alveolar surface area maximizes gas partial pressure gradients
what are the 3 main types of respiratory surfaces in animals
- air breathing terrestrial animals have INVAGINATED respiratory surfaces called LUNGS
- nearly all water breathing aquatic animals have EVAGINATED surfaces called GILLS
- Tracheae are air filled tubes in insects
what is the primary job of the respiratory system
ventilation
- active process
- maintains gas gradients so that efficient diffusion of gases at the respiratory surface can occur
- ventilation combines with perfusion = circulation of blood over gas exchange surfaces
what is perfusion
circulation of blood over gas exchange surfaces
what are the 3 gas laws
- total pressure of a mixture of gasses is the sum of the pressures of the individual gases (Dalton’s Law)
- gases move from areas of higher pressure to areas of lower pressure
- If the volume of a container of gas changes, then the pressure of the gas will change (Boyle’s Law)
what is the partial pressure of a gas?
the pressure a single gas exerts in a mixture of gases
what is the most abundant gas in the atmosphere?
nitrogen
what % of O2 is in air
21%
average atmospheric pressure at sea level?
760 mmHg
what is atmospheric pressure
the barometric pressure of all gases in the atmosphere
what is the relationship of barometric pressure and altitude
barometric pressure drops with altitude - inverse relationship
how are fish gills specialized for gas exchange?
constant, unidirectional water flow (ventilation) maximizes PO2 on gill surfaces while perfusion minimizes PO2 on internal surfaces
what are lamellae in fish
gill filaments covered by folds
- minimize diffusion path length b/w blood and water
-sites of gas exchange that allows for the concurrent flow of H2O and blood
what is concurrent exchange
when H20 and capillary blood flows in opposite directions
there is always a gradient
what is the major challenge for gas exchange in terrestrial vertebrates
breathing air requires a moist respiratory surface with a large SA exposed to air —> lots of water loss
what is tidal ventilation
bidirectional movement of air into and out of lungs by the same pathway
**mammals and most amphibians and reptiles
what is tidal volume
the amount of air that moves in and out per breath
how does tidal ventilation help reduce water loss?
allows for condensation
during inhalation, water evaporates in nasal passages,
during exhalation, water condenses (about 25%)
what are the disadvantages of having tidal breathing
tidal breathing means no concurrent exchange (less efficient) and anatomical dead spaces in airway
-both reduce efficiency of respiratory system
breathing in avians
air sacs receive air and keep air flowing through the lungs in a unidirectional flow
it takes two breaths to move air across the lung and out of the respiratory system
