respiration 2 Flashcards
how do 4 models of respiration differ
- small relies only on diffusion
- embrace circulates the external medium through the body entirely, using bulk flow
- skin uses cutaneous respiration along with circulatory transport
- mass transit uses special respiratory surface which uses bulk flow along with a circulatory transport
identify where diffusion, dissolution, and bulk flow occur in systems
diffusion: into cells
dissolution: from air to water
bulk flow: to lungs, through spiracles, through circulatory transport,
How does countercurrent blood flow differ from concurrent blood flow?
countercurrent has an equal exchange gradient across the entire respiratory surface
-concurrent flow decreases going down the flow
What is non-directional ventilation, and what are the benefits and drawbacks of such a system?
nondirectional: medium flows past the respiratory surface in an unpredictable pattern
What are the limits to cutaneous respiration?
.-requires moist/aquatic environ.
-requires small surface area
How do the physical differences between water and air determine the types of ventilation used?
O con in air is 30x greater than Ocon in water
- 30 times more water must then be ventilated
- water is more dense and viscous, so it is also more difficult to ventilate
- unidirectional usually aquatic and allows for countercurrent exchange
- tidal is airbreathers, as it allows air to flow and requires too much work in water
- air-filled tubes are used by insects for high diffusion rates in air
circulatory system function
links external and internal respiration, lying between respiratory surface and tissues
cutaneous respiration downsides
found in aquatic and a few vertebrates
- conflict between respiration and protection
- generally confined to moist/aquatic environ
- have to be small, have low surface area
specialized respiratory surfaces
allows rest of skin to be protected/thick
higher effective SA, highly vascularized, lower diffusion distance
-protected in body cavity and can be kept moist
-highly ventilated
-sync’d with circulatory system
-can either be evaginations (gills) for increased area, or invaginations (lungs), that hold external environ
-found in vertebrates
lungs adv/dis
adv: high SA can be protected, thin membrane/low diffusion distance
dis: only good in water since they lack support, easily damaged
- requires ventilation
gills adv/dis
adv: high SA, protected, can be kept moist when on land, suitable for breathing air
dis: only good in air (at the cost of ventilation)
Ventilation
movement of medium across respiratory surfaces by BULK FLOW
- either nondirectional, unidirectional, or tidal
- anatomy of resp surface determines ventilation type
- pattern, not direction can change with environmental and metabolic conditions
nondirectional
medium flows past the repiratory surface in an unpredictable pattern
unidirectional
medium enters the chamber at one point and exits at another
tidal
medium moves in and out of chamber
eupnea
normal breathing
apnea
no breathing
blood flow and medium
movement of blood through respiratory surface affects efficiency of gas exchange
- saturation of blood increases with increased CONTACT TIME btw blood and surface
- saturation decreases with decreased DIFFUSION DISTANCE btw blood and respiratory surface
increased boundary layer and blood saturation
decreases diffusion distance which decreases blood saturation of oxygen
tidal ventilation
allows medium to move in and out at the same time, so PO2 can increase while PCO2 decreases
concurrent flow
PO2 of medium and blood will equilibrate, both flow in same direction
countercurrent flow
PO2 of blood approaches that of inhalant medium
-medium and blood move in opposite directions
cross current flow
foudn in birds, vessels cross the respiratory surface
-PO2 increases with more rapid medium flow, so get better exchange the fast the circ and vent
