Question

During inspiration which spiracles are kept open and which are kept closed? (K)

Answer 1

During inspiration which is a passive process in cockroach, tergo-sternal muscles relax to increase the body cavity space hence pressure decreases. In the process, thoracic spiracles are kept open and abdominal spiracles are kept closed. Reverse is the case in expiration which is a active process and tergo-sternal muscles contract to decrease the body cavity space and pressure is increased, during this thoracic spiracles are kept closed and abdominal spiracles are kept open.