gas exchange Flashcards
what are the adaptations of gas exchange surfaces across the body surface is a single celled organism
thin flat shape and large SA:V
short diffusion distance to soo part of cell
how does the tracheal system of an insect work
air moves through sprockets in surface of insect
air moves through tracheae
which divides into tracheoles where gas exchange occurs directly to cells
- oxygen used during respiration establishing conc. gradient
- carbon dioxide produced by respiration- diffuses down conc. gradient from respiring cells
what are the adaptations of the tracheal system in an insect
thin walls —> short diffusion distance
high numbers of highly branched tracheoles —> short diffusion distance and large surface area
tracheae provide tubes of air —> fast diffusion
fluid in end of tracheoles drawn into tissues by osmosis during exercise —> faster diffusion through air to gas exchange surface and larger surface area
contraction of abdominal muscles changes pressure causing air to move in/out —> maintains conc. gradient
what are the compromises for gas exchange and limiting water loss in insects
thick waxy exoskeleton —> increases diffusion distance so evaporation less
spiracles can open and close —> allows oxygen in and carbon dioxide out and close to reduce water loss
tiny hairs around spiracles —> traps moist air reducing water potential gradient so less water lost by evaporation
what are the adaptations for gas exchange in a fish
gills have many filaments covered with many lamellae —> increased surface area for diffusion
thin lamellae wall —> short diffusion distance between water and blood
lamellae have large number of capillaries —> remove oxygen and bring carbon dioxide quickly maintains conc. gradient
what is the counter current flow in a fish
blood and water flow in opposite directions over lamellae
so oxygen conc. always higher in water than blood
so maintains conc. gradient of O2 between water and blood
for diffusion along whole length of lamellae
draw a graph for counter current flow and for parallel flow
% oxygen saturation on y
distance along lamellae on x
counter current
two lines diagonally down
water top line blood bottom line
parallel flow
two lines start at top and bottom and meet in middle horizontal y shape
draw a cross section of a leaf
waxy cuticle
upper epidermis
palisade mesophyll
spongy mesophyll
lower epidermis
stomata a guard cells
what are the adaptations for gas exchange in leaves
many stomata - large surface area for gas exchange but can close to reduce transpiration
spongy mesophyll cells contain air spaces - large surface area for gases to diffuse through
thin- short diffusion distance
what are the structural and fictional compromises between gas exchange and water loss of leaves
thicker waxy cuticle - increases diffusion distance so less evaporation
sunken stomata in pits, rolled leaves, hairs- trap water vapour, protect stomata from wind so water potential gradient between lead and air decreased so less evaporation
spines/ needles - reduced surface area to volume ratio
what is the gross structure of the human gas exchange system
trachea
splits into two bronchi
each bronchus branches into smaller tubes called bronchioles
bronchioles ends have alveoli
what are the adaptations for gas exchange in the human
many alveoli/ capillaries - large surface area
alveoli/ capillary walls are thin - short diffusion distance
ventilation / circulation - maintains conc. gradient
what are the features of the alveolar epithelium
thin/flattened cells/ one cell thick -> short diffusion distance
folded -> large surface are
permeable -> allows diffusion of carbon dioxide and oxygen
moist -> gases can dissolve
good blood supply from network of capillaries-> maintains conc. gradient
how does gas exchange occur in the lungs
oxygen diffuses from alveolar air space into blood down conc. gradient
across the alveolar epithelium then across the capillary epithelium
how does inspiration occur
- external intercostal muscles contact, intercostal muscles relax -> rib cage moves up and out
- diaphragm muscles contract -> flattens
- increasing volume in thoracic activity
- decreasing pressure in thorax
- Atmospheric pressure higher than pressure in lungs -> air moves down pressure gradient into lungs
