Gas exchange Flashcards
gas exchange method in single celled organisms
simple diffusion
simple diffusion in single celled organisms
large SA:vol ratio
O2 can diffuse into cells, CO2 can diffuse out of cells via surface membrane
sphere volume equation
4/3 X 3.14 X r3
sphere SA equation
4 X 3.14 X r2
insect gas exchange adaptations
- waterproofing-exoskeleton w waxy cuticle
- small SA:vol ratio-small area to lose water
- diffusion gradient-O2 used at tissue so more diffuses in high CO2 at tissue so moves toward trachea+ out
- ventilation-rhythmic abdominal movements, mass movement of air in+out, speed exchange
- spiracles-lose water open, close till gas exchange(CO2),control via valve
why must insects be small
to maintain diffusion gradient from surroundings to body tissue, limited by atmospheric O2 conc
insect respiratory system components
spiracle
trachea
tracheole
cell
fish respiratory system components
lamella
gill filaments
artery
fish gill adaptations
thin epithelium
counter current system
increased SA
thin epithelium advantage in fish
short diffusion pathway
why do fish need gas exchange adaptations
oxygen concentration lower in water than air
large SA advantage in fish
lamella-many capillaries, thin surface cell layer
gill filaments-large SA for gas exchange to occur over
counter current system
blood flows through lamellae one direction, water flows over them in opposite direction
-high O2 conc water always next to lower O2 conc blood
steep conc gradient maintained
what are dicotyledonous plants
flowering plants w broad leaves
gas exchange surface in dicotyledonous plants
mesophyll cells-well adapted large SA
dicotyledonous plants components
guard cell
stomata
mesophyll
guard cell open/close
open for gas exchange
close to retain water
when is external air needed dicotyledonous plants
if no balance between photosynthesis(waste product O2) and respiration (waste product CO2)
dicotyledonous plant adaptations
large SA:vol ratio
simple diffusion of gas through plant
stomata on bottom of leaves-less evaporation, shade
most diffusion in dicotyledonous leaves as
thin+flat-large sA
lower epidermis has stomata
many air spaces in mesophyll layer
what are xerophytic plants
plants adapted to living in areas with a short supply of water
adaptations of xerophytic plants
sunken stomata
hairs on leaves
rolled leaves
thick waxy cuticle
rolled leaves
trap air with high water potential in leaf
no water loss as no water potential gradient between leaf inside/outside
reduced water loss
hairy leaves
trap moist air next to leaf surface(water vapour)
reduce water potential gradient between inside/outside of leaf so less water is lost
waxy cuticle
prevent water evaporation(as does closing stomata)
sunken stomata
traps moist air-reducing water potential gradient
smaller organisms
higher SA:vol, high metabolic rate(simple diffusion, not as much needed)
larger organisms
low SA:vol, low metabolic rate(use exchange organs, mass transport)
human lung components
trachea
bronchus
bronchioles
alveoli
diaphragm, internal/external intercostal muscles
alveoli adaptations(specialised exchange surface)
large SA:vol
thin
partially permeable
surrounding + internal medium to maintain diffusion gradient
trachea adaptations
cartilage rings add strength+ allow movement
inspiration(breathe in)
external intercostal muscles contract
ribs up+ out
diaphragm contract(down, flatten)
-thorax vol increase, air pressure decrease
-air flows in(high outside pressure to low inside pressure)
expiration(breathe out)
internal intercostal muscles contract
ribs in +down
diaphragm relax(curve up)
-thorax vol decrease, air pressure increase
-air forced out(high inside pressure to low outside pressure)
fricks law
diffusion rate is directly proportional to (SA X conc. difference)/diffusion pathway length
