4.3 Gas Exchange (insects) Flashcards
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terrestrial insects
insects have an exoskeleton made up of hard fibrous materila called chitin for protection
and a lipid layer to prevent water loss
insects dont have lungs, and instead have a tracheal system
what ae insects adaptations to prevent water loss
insects have large surface area to volume ratio where water can evaporate from
insects have a water proof exoskeleton
small spiracles, where gases enter and water can evaporate from, can open and close to reduce water loss.
insects tracheal system
spiracles are round, valve like openings, running along the length of the abdomen oxygen and carbon enter and leave via the spiracles. the trachea attach to these openings.
the trachea is a network of internal tubes. the trachea tubes have rings within them to strengthen the tubes and to keep them open
the trachea branch into smaller tubes, deeper into the abdomen of the insect called tracheoles. these extend throughout all the tissues in the insect to deliver oxygen to all respiring cells
three methods of moving gases in the tracheal system
gas can exchange by diffusion as when cells respire, they use up oxygen and produce carbon dioxide, creating a concentration gradient from the tracheoloes to the atmosphere
mass transport- insects contracts and relax their abominal muscles to move gases on mass
when the insects are flying- muscle cells start respire anaerobically to produce lactate (lactic acid). this lowers the water potential of the cells, and therefore water moves from tracheoloes into the cells by osmosis. this lowers the volume in tracheoloes and therefore pressuure als decreases and so air from the atmosphere is drawn in.
adaptation for efficient diffusion
large number of tracheoloes- large surface area
walls od tracheoloes are thin and short distance between spricales and tracheoloes- small diffusion distance
use of oxygen and production carbon dioxide maintains steep concentration gradient
Explain the role of air sacs in the gas exchange system of locusts.
air sacks stores oxygen do respiration can occur in locuses
Explain the features of gas exchange surfaces that are common to both insects and
mammals.
large surface area
because many tracheoloes and alveoli
short diffusion distance
because alveoli and tracheoloes have thin walls
Compare and contrast the structure of the gas exchange system of the mayfly nymph with the adult mayfly.
similarities
large surface area
small diffusion distance
differences
nymphs have gills and adults have trachea
nymph has external system and the adult has internal system
