Respiration 

Respiration

1. External Respiration
   1. Gas exchange with the external environment Diffusion, Ventilation, etc.
   2. Gas exchange with the Internal environment
   3. Diffusion and circulatory system.
2. Internal Respiration
   1. Cellular respiration
   2. Glycolysis
   3. Kreb’s Cycle, Electron transport
      1. Oxidative metabolism in mitochondria

The Atmosphere 

Composition of Dry Atmospheric Air 

1. Table 1.1 

Water vapor in the air

1. Table 1.2
2. Composition varies with temperature 
3. Relative humidity =  % of saturation for that temperature
4. Total H₂O  = mg / liter of air 
5. 0 °C:  vapor pressure = 4.6 mm Hg 
6. 100 °C:  vapor pressure = 760 mm Hg 
7. Mammal lung at 37 °C  = 47 mm Hg

Altitude and Atmospheric Pressure

1. At sea level 1 Atmosphere = 760 mm pressure 
2. Decrease in Atmospheric Pressure with altitude (Fig. 1.1)
3. Each gas in atmosphere contributes a partial pressure to the total atmospheric pressure.
   1. P_N = 78.08% X 760mm = 600.6mm Hg 
   2. P_O = 20.95% X 760mm = 159.2mm Hg 
   3. P_CO2 = 0.03% X 760 mm = 0.2 mm Hg 

Solubilities of Gases

1. Gas molecules are soluble in water (Table 1.3)
2. Solubility coefficient ["  alpha]
3. CO₂ is about 30 times more soluble than O₂.

Effects of Pressure and Temperature 

1. Henry’s Law
   1. calculates he amount of gas that will dissolve in water (or plasma) at a certain pressure
   2. V_g = a(P_g/760)V_H20
2. Effects of Temperature and Salinity on Solubility 
   1. Table

Solubility of Carbon Dioxide

1. CO₂ Transport in Blood
   • CO₂ + H₂O <-> H₂CO₃ <-> H⁺ + HCO₃^-  <->  2H⁺ + CO₃^2-
2. Isolated tidal pool variability

Gas Diffusion 

1. solubility and rate of diffusion