Which one of the following is one of the paths followed by air or O 2 during respiration in the adult male Periplaneta americana as it enters the animal body? (a) Spiracle in metathorax, trachea, tracheloes, oxygen diffuses into cells (b) Mouth, bronchial tube, trachea, oxygen enters cells (c) Spiracles in prothorax, tracheoles, trachea, oxygen diffuses into cells. (d) Hypopharynx, mouth, pharynx, trachea, tissues
Option A The respiratory system is well developed in a cockroach in order to compensate the poorly developed circulatory system. It consists of tracheae, tracheoles and spiracles. The main tracheal trunks open to the exterior on body surface through 10 pairs of segmentally arranged apertures termed spiracles or stigmata. Two pairs of spiracles are thoracic, one between pro and mesothorax and the other between meso and metathorax. Haemocoel contains a network of elastic, closed and branching air tubes or tracheae. The ultimate finer branches of tracheae are called tracheoles which come in contact with the individual body cells. The elaborate tracheal system carries oxygen directly to all the body cells.
