1. (Terrestrial) RESPIRATION:
When AIR is the respiratory Medium….
Benefits over water:
Higher O2 content
Better diffusion rates
Less of a need to ventilate
Biggest obstacle to overcome:
NEED A MOIST MEMBRANE!!!
Insects (the main category of terrestrial invertebrates) have “TRACHEA”:
Highly branched air tubes which extend to nearly every cell
Air is taken in through small pore on their sides called “SPIRACLES”
LUNGS!
Terrestrial Vertebrates (of course) have _________
There are 2 main strategies for breathing:
POSITIVE & NEGATIVE PRESSURE

2. Positive or Negative ...what’s YOUR pressure?
Positive Pressure Breathing
Example:
Air is forced down into the lungs by use of a mouth pouch
Negative Pressure Breathing
(Most other lunged animals)
Thoracic cavity enlarges by:
Action of the rib muscles, yes….
Both lower pressure
In the lungs to below
Atmospheric Pressure.
But mostly due to:
Contraction of the diaphragm.
Tidal Volume-
Amount of air an animal breaths in a normal breath
Vital Capacity-
Maximum air volume during forced breathing
(There will always be some Residual Volume: the amount still remaining…)

3. Bird Respiration: Kenny G. You ain’t got nuthin’!!
…a very complex system!!
Besides lungs, they have 8-9 air sacs in their abdomen:
Serve as bellows to a continuous movement of air
Air channels continuously through “Para bronchi”
Animate!

4. Control of Breathing: a lot is just in your head…
Breathing Control Centers of the Medulla Oblongata & Pons:
Send impulses to rib muscles & diaphragm
Monitor blood & spinal fluid pH:
As CO2 levels rise 
pH lowers 
Tempo of breathing increases
Loading & Unloading of O2 & CO2
Remember! Gases diffuse down their concentration gradient!!
Blood arriving in lungs has a lower Po2 and higher Pco2 than the air in the alvioli
OXYGEN:
Carried by hemoglobin (Iron containing pigment)
What’s Hemoglobin again?
Protein with a 4 subunits: alpha & beta
Each subunit binds one O2 molecule
COOPERATIVITY: binding of first subunit
changes the shape of the rest of them and
increases their affinities.
Bohr Shift- O2 has lower affinity at lower pH

5. CO2 Transport: a little more tricky
Transported in 3 ways:
1. 7% is dissolved in plasma.
2. 23% bound to amino groups of hemoglobin.
3. A full 70% as a bicarbonate ion.
In erythrocytes,
CARBONIC ANHYDRASE converts CO2 into the bicarbonate.
CO2 + H2O  Carbonic Acid
Carbonic Acid dissociates into Bicarb + H+
Reverses in Lungs