ventilation in insects

Question 1

what does the gas exchange in insect involve

Answer 1

tracheal system made up of spiracles and trachea

Question 2

what are spiracles

Answer 2

small openings found along thorax and abdomen

can be opened and closed by sphincters

gases enter for exchange, site for water loss

bristles, filter unwanted particles out of air, prevent damage to the gas exchange surface

trap moist air, help reduce water loss

Question 3

how is gas exchange in insect controlled

Answer 3

relatively high oxygen demand

to increase oxygen demand, spiracles open when
- need lots of oxygen
-carbon dioxide builds up

reduce water loss
spiracles close when
- oxygen demands are lower
-environment is dry

Question 4

what is the tracheae

Answer 4

run from spiracles into tissues

covered in chitin, support tracheae, prevent collapsing, keeping airway open, prevent gas exchange

Question 5

what are tracheoles

Answer 5

branches from tracheae

penetrate into individual body cells

elongated cell no chitin, gas exchange possible

many branched, large surface area

walls thin, reduce diffusion distance

moist walls, dissolves in moisture, diffuse into fluid

Question 6

what supplies all oxygen needed by cells of an insect

Answer 6

tracheal system

Question 7

what are tracheal fluid

Answer 7

at the ends of tracheoles

limits how far along air can diffuse along tracheoles

muscles of insect star respiring anaerobically, produce lactic acid, builds up in muscle, lower wp, water move out tracheoles into respiring cells, more SA exposed for more efficient gas exchange to help meet increased demand for oxygen

Question 8

how does larger insect supply extra oxygen

Answer 8

mechanical ventilation of tracheal system
collapsible enlarged tracheae or air sacs

Question 9

how does mechanical ventilation work

Answer 9

insect actively pumps air into system by rhythmic contracting muscles of thorax/abdomen

when insects flying, they use their wing movements to pump thorax

thorax volume increase, pressure decreases, air flows in

thorax volume decreases, pressure increases, air flows out

Question 10

how does air sac help ventilation

Answer 10

act as reservoirs, storing extra air til needed

squeezed by action of flight muscle, repetitive expansion/ contraction of air sacs ventilates the tracheal system

increases amount of air moved around gas exchange system