lecture 13 Flashcards
where can gases diffuse easily
within the lungs and the tissues
why doesnt oxygen diffuse well in water
because it is a non polar molecule and water is polar
ectotherms have what type of metabolic rate
low metabolic rate, low 02 demand, and water is ok (cold blooded animals)
ectotherms have no
internal temp regulation
endotherms have what type of metabolic rate
high metabolic rate, high 02 demand, need air (warm blooded)
endotherms have
internal temp regulation
small animals like flatworms have digestive and neurons but no
respiratory system because all cells are within 0.5 distance
krogh’s rule
all cells must be within 0.5mm of 02 source
what is a limitation to having no respiratory system
they have to stay small because if they get big, the cells will no longer be within that 0.5 distance
large respiratory surfaces
surface for diffusion and gas exchange
what are the respiratory surfaces for water and air breathers
water: gills air: lungs
what do these large respiratory surfaces optimize 2 things
they optimize the fick equation by 1. increase surface area which allows more diffusion 2. decrease the distance so these surfaces are as thin as possible causes INCREASE DIFFUSION RATE AND FASTER DELIVERY RATE
fish have gills allowing what three things
high surface area, high ventilation, high perfusion
ventilation
water movement in one direction over the gills
perfusion
highly organized blood vessels allows gas exchange
blood that passes by the gills, leaves
oxygenated
as blood and water are in contact, oxygen will diffuse from
high partial pressure to low partial pressure
fish have what type of gas exchange
countercurrent gas exchange
countercurrent gas exchange
water enters in the opposite direction that blood is flowing and causes the deoxygenated blood to face deoxygenated water but theres still enough partial pressure for the diffuse of oxygen to occur. as the water moves right, the partial pressure is getting smaller but still enough to move gases (most in animal kingdom)
concurrent gas exchange
water enters at the same side as the blood, and o2 meets with the deoxygenated blood and this causes massive partial difference so lots of 02 moves into blood but as water moves in one direction, oxygen is given off and the difference gets smaller and smaller until it reaches equilibrium
how do insect breathe
they have a series of branching air tubules in their bodies called tracheae that are not ventilated nor perfused, they branch until theyre 0.5 away from cells, air just diffuse
for the way that insect breathe, they dont need
circulatory systems
most air breathing vertebrate use
tidal ventilation
tidal ventilation
active breathing , air flows in and out the same path (not unidirectional) and air mixes at respiratory surfaces
what occurs to partial pressure when we inhale and exhale
when we inhale we have full partial pressure but as it reaches the respiratory surface to meet blood, it losses that full partial pressure (100->60)
why is losing the full partial pressure not an issue for us
we have air readily accessible compared to fish who live in water
alveoli
structures with high surface area with very thin epithilium where diffusion of oxygen occurs
how do lungs and gills help increase gas diffusion
by increasing area and decreasing distance
what type of gas exchange process do birds use
they use both countercurrent gas exchange and air breathing which includes unidirectional air flow, high perfusion, and can deal with low partial pressure NO TIDAL FLOW
how do birds breathe
- air flows into the trachea then into the posterior air sac or the respiratory surface (the air that enters divides) 2. as air flows into the respiratory surface (parabronchi) blood flows the other direction (good partial pressure) 3. exhalation occurs from the posterior air sacs to trachea.
birds have what same two things mammals do
shory diffusion distances and large surface areas
small animals are able to diffuse gases
directly to cells and the environment
bigger animals rely on
perfusion and ventilation
most terrestrial animals use
tidal flow through lungs
