Respiration Flashcards
What factors determine diffusion rate of respiratory gases?
Surface area or respiratory surface
Thickness of respiratory surface
Metabolic demands
What are the constraints on the rate of gas exchange?
Molecular weight of diffusing gasses
solubility
temperature
What are the components of the respiratory system?
Specialised surface areas where gas exchange takes place
Breathing mechanisms to bring fresh air/water to the surfaces
Circulatory mechanisms for transporting gases
How do insects respire?
Via spiracles, air diffuses through them, trachaea inflate and deflate to pump air through. Trachaea branch into tracheoles
Tidal ventilation – gases exit same way as they enter.
What happens to spiracles when environment is dry?
Close to reduce water loss, air sacs can store air for when they close
What happens to oxygen saturation of haemoglobin with temperature increase
Oxygen saturation is lower with higher temperature
What is the Bohr effect?
Shows haemoglobin’s oxygen binding affinity is inversely related both to acidity and to the concentration of carbon dioxide. CO2 reacts with H2O to form carbonic acid, which lowers pH. Additional oxygen released at lower pH .
How are fish adapted for gas exchange?
Short diffusion distance
Water flows in a single direction
Countercurrent flow
Describe the counter current flow in fish
Water flows in opposite direction to blood, , gases are exchanged
How do birds respire?
Birds don’t have a diaphragm, instead air is moved in and out by pressure changes in air sacs
First inhalation: Air enters posterior air sacs; these expand
First exhalation: Air forced into the lungs; gas exchange occurs
Second inhalation: Air moved to anterior air sac
Second exhalation: Air pushed out of body
What adaptations do birds have for gas exchange?
Air sacs expand and contract
Unidirectional flow of air
Crosscurrent flow of air and blood
Huge SA for gas exchange
What happens when mammals inhale?
Intercostal muscles contract
Diaphragm contracts
Pressure inside chest decreases
Air rushes in
What happens when mammals exhale?
Intercostal muscles relax
Diaphragm relaxes
Pressure inside chest increases
Air forced out
What adaptations do mammals have for respiration?
Lungs are inside the body which decreases water loss
Lots of alveoli, which provide a thin surface and lots of area
Why is ventilation in mammals limited?
Tidal ventilation, Air enters and leaves via the same path and not all air is exhaled, so the percentage of air that is oxygen is lower within lungs than in outside air
