fuck this final bullshit

Question 1

how do mediums interact w lungs, internal gills, and external gills

Answer 1

lungs: medium enters the body

ext gills: projection into the environment that allows medium to pass over

int gills: projection outward but also covered, so medium passes into a superficial cavity

Question 2

when we breathe we dont soak up all the O2 in the air. why is this the case? does it matter?

Answer 2

environ pO2 doesn’t reach the full area of the alveoli

however this doesn’t matter that much because there’s so much air around us, we constantly have access for it so there’s never really been a need to adapt to fix it

Question 3

how does co/counter current exchange work? which is more efficient?

Answer 3

co: medium and blood flow move in the same direction.

counter: medium and blood flow move in opposing directions.

counter is more efficient. initially, co- has a gradient; however, it disappears as blood pO2 and medium pO2 converge. this is contrasted against counter-, which maintains a pO2 gradient at all times favouring inward diffusion

Question 4

how does crosscurrent gas exchange work?

Answer 4

unique to birds

across a medium, blood flows in the same direction. however, blood flows in multiple pathways, such that there is always a diffusion gradient favouring inward diffusion of O2. this is the most efficient pathway

Question 5

there’s some dead space in lungs. why does it show up? what is the point of it?

Answer 5

‘dead space’ is the air chillin in the bronchioles. no diffusion occurs in the bronchioles (it occurs in the alveolus) so its considered ‘dead.’

Question 6

in lung there’s a ton of stuff. what do they do:
- pores of khan
- type I pneumocyte
- type II pneumocyte
- WBC

Answer 6

pores of khan equalize pressure bw alveoli so they can inflate

type I pneumocyte: facilitate gas exch

type II pneumocyte: secrete surfactant that makes sure alveoli aren’t sticking together

WBC: clears out all the shit u breathe in

Question 7

what is the pre-botzinger complex? what does it do? why can we manually override it?

Answer 7

regulates natural breathing to the hypoglossal nucleus

manual override is for times of stress ex. diving underwater, holding breath in presence of toxins, etc

Question 8

how do internal/external intercostal muscles interact to cause breathing

Answer 8

breathe in: int relax, ext contract

breathe out: int contract, ext relax

Question 9

what is the point of residual volume?

Answer 9

to make sure gas exch always favours inward diffusion

Question 10

what are some adaptations of animals at higher altitudes?

Answer 10

respiration rate incr (at the risk of higher CO2 prod)

prod more RBC to incr carrying capacity of O2

Question 11

how does bird breathing work?

Answer 11

1. inhale
   the air sacs expand, drawing air in
   our breath now resides in the post air sac
2. exhale
   the air sacs contract, forcing air out
   our breath moves across the parabronchi for cross-CE
   our breath now resides in the post air sac
3. inhale
   the air sacs expand, drawing air in
   our breath now resides in the ant air sac
4. exhale
   the air sacs contrast, forcing air out
   our breath moves out the lungs and we have our ‘true’ exhale

Question 12

what are some trends we observe for respiratory surface density vs body size?

Answer 12

1. birds are superior in every respect
2. as animals get bigger, resp surface density decr (why do they need less resp density?)

Question 13

fleas have hella trachea for breathing. how is this advantageous? limiting?

Answer 13

+ hollowness = very light
- can only have so much trachea bc u need to make room for other shit (muscles, organs, etc)
to this end, there’s a big size limitation

Question 14

hypothesis: there’s a cost assoc w having larger trachea. how are we gonna tackle it?

Answer 14

look at a bunch of beetles thats how. idiot.
findings!
- trachea density gets higher in legs way faster than the rest of the body (supplying O2 to leg muscles directly)

basically beetles are predicted to only be at max 17cm and woah! the max beetle length recorded is about 16.7 cm

Question 15

as frogs metamorphose, they change their gas exchange method. explain this.

Answer 15

for O2 uptake, diffusion occurs mainly through the skin and gills until the lungs develop, at which point they take over

for CO2, diffusion occurs mainly through the skin throughout all points of development.

[we may observe this due to evo adaptations - if capillaries are naturally close to the skin and theres a gradient, fuck it might as well work with it]

Question 16

there is zeta, epsilon, gamma, beta, and alpha subunits for fetal and individual development. explain them.

Answer 16

alpha are the base - at any given point, we have two of them

Z + E are for grabbing the A/B subunits from the mother

G are for grabbing O2 from mother, and have a higher affinity for O2 than A/B subunits

Question 17

what about heme makes oxygen want to bind?

Answer 17

the iron in the centre

Question 18

what is cooperativity? if we were to graph it, what type of relationship would we see?

Answer 18

cooperativity is the idea that, as some oxygen is recruited onto the hemoglobin, more will be recruited in response. this is good for delivering lots of O2 to the body

we would see an S curve - exponential in the beginning as oxygen cooperates, then plateauing off as Hb becomes fully saturated

Question 19

the more u respire, the more O2 u need. what mechanisms help ameliorate this tension.

Answer 19

cooperativity again!
the more u respire, the more O2 will be given up from Hb to myoglobin, which can use O2 for the muscles
(myoglobin has a higher affinity)

Question 20

on a % saturation vs pO2 graph (p50) what does a left/right shift indicate

hey what even is a p50 anyways

Answer 20

left shift indicates higher affinity (gets to higher % saturation at lower pO2)

right shift is the opposite

p50 can functionally be thought of in a similar vein to our Km for enzymes, whereby p50 is the amount of time it takes for Hb to reach 50% saturation
(ie more time it takes = lower affinity)

Question 21

what is the effect of acidity on p50? (describe the bohr effect)

Answer 21

acidity decreases affinity = increases time it takes to reach p50 = right shift

the bohr effect: as CO2 incr in blood, Hb affinity for O2 decr. this means that Hb gives up its O2 more easily to myoglobin.
since CO2 is a metabolism byproduct, the implication (to the body) is that metabolism is going crazy and that the muscles need more O2

Question 22

what is the effect of temperature on blood?

Answer 22

higher temp = decr affinity = more time to reach p50 = right shift

remember! Hb is a protein!

Question 23

what is the root effect? why is this important for fish swim bladders?

Answer 23

acidifiation causes an absolute decrease in the amount of carrying capacity of O2

[jury’s still out on the fish bladder part]

Question 24

wooly mammoth leg muscle/O2 carrying capacity paradox. thoughts?

Answer 24

theoretically wooly mammoth legs, being so muscular, would require lots of O2 and thus a higher O2 carry capacity. at the same time, heating the extremities is inefficient, but cold legs would be terrible for O2 carrying capacity.

it was found that wooly mammoth adapted by having Hb insensitive to temp changes

Question 25

arterial O2 and venous O2 conc both change based on swimming speed (exertion).

Answer 25

arterial O2 conc doesn’t change based on exercise level. however, venous O2 conc decr more and more. this means that venous O2 (in the heart) decr, until eventually the heart fails from lack of O2

Question 26

octopi have different respiratory pigments than we do. how do they get by?

Answer 26

• branchial hearts for extra pumping
• venous return is almost entirely deoxygenated - extremely efficient at extracting O2

Question 27

for primates, what is the relationship between size and oxygen affinity

Answer 27

as body size increases, oxygen affinity increases (p50 decreases)