Insect and fish gas exchange

Pores

Spiracles

Spindles

Stomata

breathing

abdominal pumping

respiration

gas exchange

oxygen

glucose

carbon dioxide

water (vapour)

Many Filaments

Many Spiracles

Many Lamellae

Many Gills

Blood in the capillaries flows in the opposite direction to water outside the lamellae

Blood in the capillaries flows in the same direction to water outside the lamellae

Blood in the capillaries is always next to water that has a higher oxygen concentration

Diffusion of oxygen from the water into the blood occurs along the whole length of the gill

Lamellae walls are very thin

Walls of traceoles are very thin

Cells are very close to the end of each tracheole

Capillary walls are just a single layer of flattened cells

Lamellae walls are very thin

Tracheole walls are very thin

Closing their spiracles, periodically

Opening their spiracles, periodically

Closing their tracheoles, periodically

Opening their tracheoles, periodically