1. Respiration Use of O2 from the environment and the disposal of CO2
Physiological challenge
Aquatic vs Terrestrial

2. Environments Terrestrial Aquatic 5-10ml O2/liter H2O
Atmospheric conditions
78% N, 21% O2, 1% others, .03% CO2
1 liter of air = 210 ml 02
Aquatic
5-10ml O2/liter H2O
Environmental Conditions
Anoxic
Hypoxic
Normoxic
Hyperoxic

3. Organismal Categories
Obligate Aerobe
Facultative Anaerobe
Obligate Anaerobe

4. How would you build a gas exchanger?
Expose it to the source of gas (ease of exchange not a lot of energy needed)
Highly vascularized
(ease of movement into body)
Thin membrane
(easy transfer – not too thin - lack durability)
Large surface area
not too large lose H2O

5. Respiratory organs Aquatic vs Terrestrial Tracheae System Gills Lungs
Skin

6. Gills External gills evaginations Internal gills
Invaginations (covered by flap - operculum)

7. Gill Structure Gill Arch Gill Filament Gill Lamellae
Directional – countercurrent
Fish Cough

8. Why is countercurrent more efficient?
Parallel blood and oxygen flow – equilibrium is reached when each has 5 ml oxygen – 50% efficiency
Blood 0ml Oxygen/liter 0ml to ml
Water 10ml Oxygen/liter 10ml to ml
Countercurrent blood and oxygen flow – equilibrium is seldom reached, so diffusion continues – 100% efficiency
Blood 0ml Oxygen/liter 0ml to ml
Water 10ml Oxygen/liter 10ml to ml

9. 2 ways Fish get H2O across to extract O2
Ram Jet ventilation
Opercular pump

10. Tracheae System Spiracles – holes on side of body
Tracheae system – internal plumbing
Diffusion – directly into cells – no circulatory system necessary

11. Respiration in Amphibians and Reptiles
Positive pressure breathing
> pressure outside lung
MECHANISM -Into pharynx – close entrance – lungs expel CO2 - elevate floor of oral cavity and open glottis
Negative pressure breathing
lung expansion – pulling accordian – rib cage expansion

12. Mammal Lungs
Increased O2 demand/higher metabolic rate = more efficient system
Structures
Nostrils – Hair Filter
Ciliated cells of R.T.
Larynx
Trachea
Bronchi/Bronchus
Bronchioles
Alveolar sac
Alveoli
Diaphragm
Alveolar sac
Alveoli

13. Structure & Mechanisms of Breathing
Route = trachea, bronchi, bronchioles, alveoli – capillaries
Boyle’s law
Volume increases pressure decreases
Muscles involved
External Intercostals
Diaphragm
Inspiration – Diaphragm and Intercostals contract
Expiration – muscle relaxation and elastic recoil

14. Breathing Measurements
Tidal Volume
total amount of air moved with each breath at rest = ~ 500 ml
Vital Capacity
Maximum amount that can be expired after a forceful maximum inspiration = ~ 4.6 L in males and 3.1 L in females
Dead Air Space
Amount of air contained in areas of no gas exchange = ~ 150 ml of Tidal Volume

15. Birds Respiratory System Structure Mechanism Unidirectional flow
No dead air space
Efficiency

16. Skin – Cutaneous Respiration
Oxygen – white
Carbon Dioxide - black