gas exchange in insects

Question 1

spiracles

Answer 1

-found along thorax and abdomen of insects
-site of entry and exit of respiratory gases

Question 2

what controls movement of spiracles

Answer 2

sphincters which open or close spiracles which is of great value to control of water loss

Question 3

trachea

Answer 3

-largest tube for respiration
-air directly into body for gas exchange
-

Question 4

what are trachea supported by

Answer 4

spirals of chitin same material that makes up insect cuticle

Question 5

function of chitin spirals

Answer 5

hold trachea open if squashed or deformed unlike rings of cartialage of mammalian trachea

Question 6

feature of chitin

Answer 6

makes trachea impermeable to gases to no gas exchange takes place here

Question 7

structure of trachea

Answer 7

divide to form narrower and narrower tubes until they branch out into tracheoles

Question 8

tracheoles

Answer 8

-narrow tubes
elongatec cell
no chitin lining
-free to gases
-small
where most gas exchange takes places

Question 9

site of gas exchange for insects

Answer 9

tracheoles

Question 10

how insects minimise water loss

Answer 10

air enters spiracles
-spiracle spinchters kept closed as much as possible

Question 11

what happens when insect active

Answer 11

usually inactive spiracles open to let more gases in for active tissues

Question 12

what limits penetration of gases for diffusion

Answer 12

-tracheoles may contain water towards end of their length

Question 13

what happens to tracheoles when insect active

Answer 13

-lactic acid builds up in muscle tissue
-effects osmotic conc of cells and water moves out of tracheoles via osmosis
-exposes additional surface area for gas exchange

Question 14

what happens to 25% of co2 produced

Answer 14

lost directly through cuticle

Question 15

how is opening and closing of spiracles coordinated

Answer 15

-by respiratory centres in nervous system
-stimulated by increase in co2 levels and lactic acid build up in active tissues

Question 16

mechanical ventilation

Answer 16

-air actively pumped into tracheal system
-spiracles open and insects make muscular pumping movement of thorax
-ventilating movements change volume and pressure of air
-draw air in and out of trachea and tracheoles

Question 17

collapsible trachea or air sacs that act as air reservoirs

Answer 17

-increase volume of air moved through respiratory system
-ventilating movements of thorax and abdomen inflate and deflate them
-some insects can have ventilation form body movement