What is the equation for rate of gas exchange?
r=(∆P x A x T x S)
(D x √Mw)
r= rate of diffusion ∆P= difference in partial pressure A= surface area T= temperature S= solubility D= distance Mw= molecular weight
Describe insects 3 ventilation mechanisms
1) Trachea inflate and deflate pumping air through
2) Rhythmic body movements
3) Tidal ventilation
What are 3 ways insects balance oxygen intake with loss of water?
1) Spiracles open and close indifferent environmental conditions
2) Hairs around spiracles trap water
3) Air sacs can store air for when spiracles are closed
Describe how temperature affects haemoglobin saturation in closed circulatory systems
- Increased temp= decreased affinity of haemoglobin for oxygen- oxygen disassociates
- Tissues that respire rapidly produce a lot of heat, increased c02 supply to respiring tissues
Describe how pH affects oxygen affinity?
- Lower pH= lower 02 affinity of haemoglobin
- Higher C02 levels = Lower pH
- Additional oxygen released
Describe bird ventilation
- Each breath takes 2 inhalations and exhalations
- Anterior and posterior air sacs
- Air sacs push air through lungs and out the body
What are 4 adaptions for gas exchange in birds?
1) Air sacs expand and contract
2) Unidirectional flow of air= increased concentration gradient
3) Crosscurrent flow of air and blood
4) Huge surface area for gas exchange
Describe the ventilation system in mammals
Inhalation:
- Intercostal muscles contract
- Diaphragm contracts
- Pressure decreases
- Air rushes in
Exhalation:
- Intercostal muscles relax
- Diaphragm relaxes
- Pressure increases
- Air forced out
What are 2 adaptions of mammals to aid ventilation?
1) Lungs inside body, decreases water loss
2) Alveoli have large surface area, 1 cell thick
What is a limitation of mammals ventilation?
Tidal ventilation- air enters and leaves through the same path
- not all air is exchanged
- % of air that is oxygen is lower within lungs than in outside air
3 adaptions of marine mammals ventilation systems
1) Store oxygen in muscles
2) More efficient at extracting oxygen
3) Can temporarily cut off circulation to some parts of the body
