Spiracles

Definition

Spiracles are small external openings found on the body of certain animals, primarily arthropods such as insects and some arachnids. They function as part of the respiratory system, allowing gas exchange to occur.

5 Must Know Facts For Your Next Test

1. Spiracles are typically located along the sides of the thorax and abdomen in insects.
2. They play a crucial role in the tracheal system by providing an entry and exit point for oxygen and carbon dioxide.
3. Some aquatic arthropods have modified spiracles that function differently from those in terrestrial species.
4. Spiracle openings can be regulated by valves to minimize water loss in dry environments.
5. Certain flatworms and nematodes do not possess spiracles, relying instead on diffusion across their body surface for respiration.

Review Questions

• What is the primary function of spiracles in arthropods?
• How do some arthropods minimize water loss through their spiracles?
• Why don't flatworms and nematodes have spiracles like some arthropods do?

Related terms

Tracheal System: A network of small tubes in insects that transports oxygen directly to cells.

Gills: Respiratory organs found in many aquatic organisms used to extract oxygen from water.

Cutaneous Respiration: The process where organisms breathe through their skin, common in flatworms and some amphibians.