Gas Exchange Flashcards
Small organisms will have a ____ SA:V ratio
Bigger
What does having a smaller SA:V ratio mean
Larger distance from the middle to the outside
Do large organisms have a higher or lower metabolic rate
Higher
Adaptations of large organisms for efficient has exchanged
- Villi and microvilli - efficient digestion of food
- Alveoli and bronchioles - efficient gas exchange mammles
- Spiracles and tracheoles - efficient in insects
- Gill filaments and lamellae - efficient in fish
- Thin wide leaves - efficient in plants
- Many capillaries - tissue
Human gas exchange system
- Alveoli
- Bronchioles
- Bronchi
- Trachea
- Lungs
Ventalation
Inhaling and exhaling
Controlled by diaphragm
Interaction between external and internal intercostal muscles
Inspiration
Diaphragm contracts
Increases lung volume
Decrease pressure in lungs
External intercostal muscles contract and pull up while internal intercostal muscles relax
Air moves into lungs
Expiration
Diaphragm relaxes
Decrease in lung vol
Increase in pressure in lungs
Internal intercostal muscles contract pull down
External intercostal muscles relax
Air moves out lungs
Alveoli
Large surface area
Tiny air sacs
Thin to minimise diffusion
Surrounded by capillaries
Maintain conc gradient
What size SA:V ratio do fish have
Small
Where is fish has exchange surface
Gills
Fishes adaptation
Countercurrent flow
What is countercurrent flow
Adaptation for gas exchange for fish allowing them to Maintain a concentration gradient to enable diffusion
What do hill lamellae provide
Large surface area 90’ angles
What do gill lamellae provide
Short diffusion distance due to capillary network
Thin
Process of counter current flow
Water flows over the gill in opposite direction to flow of blood In capillary’s
Ensures equilibrium cannot be reached
Diffusion gradient maintained across gill lamellae
What are insects exoskeleton made from
Hard fibrous material for protection
Lipid layer preventing water loss
What system to insects use for gas exchange
Tracheal system
Tracheal system is composed of ?
Trachea
Tracheoles
Spiracles
Describe the tracheal system
Oxygen and carbon enter and leave via spiriacles
Trachea attaches to openings
Trachea network of internal tubes with rings of cartilage to keep them open
Trachea branch into tracheoles
Extend throughout tissue to respiring cells
Adaptations for gas exchange in terrestrial insects
- Large number of tracheoles
Greater SA - Walls of tracheoles are thin
Short diffusion pathway - Use of oxygen production of carbon
Steep diffusion gradient
What happens when cells respire
Gas exchanges by diffusion
Use up oxygen
Produce carbon dioxide
Establishes conc gradient
Second method of gas exchange in insects
Mass transport
Insect contracts and relaxes abdominal muscles to move gases
Three ways gas moves in insects
Mass transport
Diffusion
Flight
Affect for flight on movement of gas in insects
Muscle cells respire anaerobically
Produces lactate
Lowers water potential
Water moves from tracheoles into cells via osmosis
Decreases vol of tracheoles
More air drawn in
How insects limit water loss
- Small SA:V minimise evap
- Waterproof exoskeleton
- Spiracles can open and close
Xerophytic plants
Plants adapted to survive in environments with limited water
Adaptations of xerophytes
- Curled leaves to trap moisture
- Thick cuticle reduces evaporation
- Longer root network reach more water
- Hairs trap moisture
Respiration
Chemical reaction which releases energy in form of ATP
Ficks law
Diffusion = SA x diff in conc
Length of diff pathway
Gas exchange at a stomata
- Oxygen diffuse out stomata
- Co2 diffuse in through stomata
- Reduces water loss by evaporation stomata closes at night
