Zoology 484 M.P.Wenderoth

November 7, 1997

Respiration I

The Exchange of Gases

Readings: Randall Chapter 13

fuel + O2 CO2 + H2O + ATP +heat

Role of respiratory system to supply O2 and remove CO2 from the body.

O2 and CO2 are transferred passively across tissues by diffusion

M = D A (a1-a2)/T (Fick's Law)

VO2 = D A (P1-P2)/T

How much oxygen is available in Air and Water?

Air 1 ATM -sea level (760 mmHg)

Dalton's Law of Partial Pressures

mmHg

Oxygen(O2)-------------20.95%------159-- (.21 x 760)

Carbon Dioxide(CO2)------.03%-------.3-- (.03 x 760)

Nitrogen (N2)----------78.09%----- 597-- (.78 x 760)

Water:

(1)-solubility of gas

15 at 1 atm pressure (100% of the gas)

-(2) pressure of gas

-(3)temperature of water

------------- Fresh (ml O2/L)------ Salt (ml O2/L)

-(4) amount of solutes in water

Water vs. Air

compare mass, viscosity, diffusion rates

Larger animals have developed a respiratory system to facilitate their exchange of gases. Characteristics of respiratory systems:

1. Ventilation --Mechanism to move air or water over respiratory surface()

2. Respiratory epithelium

3. Blood supply to transport gases to and from tissue

respiratory pigment for transport of O2

4. Large surface area for increased diffusion of gases at the lungs and at the tissue

Respiration in a water environment

A.. The Vertebrate Gill

B. Respiration via the skin in vertebrates