Gas Exchange in Insects & Fish

Question 1

What does efficiency of gas exchange systems depend on?

Answer 1

high surface area
short diffusion distance
high concentration gradient

Question 2

What is gas exchange in insects?

Answer 2

air enters through holes called spiracles
O2 diffuses down concentration gradient along the trachea
trachea are closely surrounded by cells
O2 diffuses into cells - ventilation helps to maintain a high conc^ gradientt

Question 3

What is water loss in insects?

Answer 3

body is covered by a waxy cuticle which reduces evaporation

insects can close their spiracles

Question 4

What is gas exchange in fish?

Answer 4

filaments and lamellae have big surface area which increaes efficiency of diffusion

thin epithelium - short diffusion distance

counter current flow = blood and water move in opposite directions which maintains a high conc^ gradient

water is always next to blood with a lower conc^ of oxygen

circulation of blood replaces blood that is saturated with oxygen

ventilation of H2O