Theme 20: Respiration 2 Flashcards
True or False: Water is a favorable membrane for getting oxygen.
False, it is unfavorable because its not as easy (this applies to all animals which can get oxygen from either)
What is diffusion helped by?
Convection (ventilation) - stirring around of the gas exchange
Why must the body convecte?
otherwise you will eventually be left with no oxygen
What are the three mediums for oxygen to be transported?
blood
air
water
what do blood, air, and water have in common?
they are the three mediums for oxygen to be transported in
why were gills developed?
because the larger the area the more gas flow and they are also proportional to the partial pressure gradient
What two things can you do to help the gradient move along?
Breathing (ventiation)
circulation
What will making the thickness of the alveoli wall thinner do?
help large molecules dissolve better
true or false: CO2 can be diffused more easily than O2.
True, oxygen is almost insoluble in water so you need hemoglobin to get O2 in
What are the four mechanism that vertebrates use for gas exchange?
Fish gills
bird lungs
mammalian lungs
amphibian skin
How do amphibians diffuse oxygen?
through their skin (salamander)
What does the Cutaneous Gas Exchange represent?
an “open model” where amphibians have thin, well vascularized, moist, naked skin
Which has the most cutaneous gas exchange?
a) Mudpuppy
b) trout
c) human
mudpuppy
Why is the bullfrogs metamorphosis a good model for evolution of air breathing?
it starts out using its skin for diffuison, then skin and gills then skin and lungs
What are the advantages and disadvantages of external gills?
Ad: lots of ability to get oxygen
Dis: vulnerable, can be eaten, if taken out of water they collapse
What are the differences between fish gills and external gills?
fish gills are internal
What is the flow of water and oxygen through gills called?
Counter current flow
What is counter current flow?
an efficient system where the blood leaves oxygenated more than the outer oxygen concentration in water
what is the double pumping mechanism in body and cartilagious fish?
a valve that lets water in the mouth, through the gills and closes so the water has to go out the opercular cavity
What is ram ventilation?
Fish like sharks and mackerel that have to oxygenate their body by moving to oxygenate their blood, if they stop moving, then no oxygen
what does the operculum act like in fish?
a suction pump to pull the water in and then a pressure pump to expel the water out
What are lamellae and what do they do?
secondary gill filaments that increase surface area for the gases and act as sieves for water flow
What is Counter current arrangement?
blood flow from tail to head (hence counter current), and this is efficient for getting the oxygen to the blood
Why are counter current gas exchangers so efficient?
- pressure of dissolved oxygen starts at venous partial pressure then is oxygenated at the secondary lamellae and moves the opposite direction
- pressure is kept constant so the oxygen constantly is flowing in
- arterial blood has a higher gradient than the expired water
What is the Fick equation?
basic physics of gas exchange, diffusion of oxygen is driven by the pressure gradient
What are the four vertebrate gas exchanges?
open
pool
countercurrent
crosscurrent
What is Open gas exchange?
through the skin (cutaneous gas exchange) external gills are a method of expanding surface area (important in tadpoles)
What is counter-current gas exchange?
fish gils
most efficient gas exchange organ in terms of transfer of gas into blood
- PaO2( oxygen concentration in arterial blood) is greater than PEO2 (oxygen concentration in expired water)
What does amphibian metamorphosis represent (transition)?
skin
to external gill
to internal gill
to lung as gas exchange organ
