Q.Which structure seals the larynx when we swallow?

Insects respire using a tracheal system: air enters through spiracles on the body surface and is carried directly to the tissues through a branching network of tracheal tubes, without needing a circulatory carrier like haemoglobin.

Unlike vertebrates, which use lungs and blood (via haemoglobin) to transport oxygen from the respiratory surface to the tissues, insects use a tracheal system for gas exchange. Air enters the body through small external openings called spiracles, located along the sides of the thorax and abdomen. From each spiracle, a network of branching tubes called tracheae carries air deep into the body, dividing repeatedly into finer and finer branches called tracheoles, which come into direct contact with individual …

Insects breathe using a branching system of tracheal tubes that carry air from external spiracles directly to individual tissues.

Insects have an open tracheal respiratory system, distinct from lungs or gills:

• Spiracles (small openings along the sides of the thorax and abdomen) let air enter and leave the body.
• These lead into tracheae — a network of chitin-lined tubes that branch repeatedly into finer tracheoles. …