Question

With the help of neat labelled diagram, explain circulatory system in cockroach.

Answer 1

Cockroach being an insect posses an open circulatory system. Animal contains an open type of circulatory system with blood flowing in blood spaces. The blood of the animal is without respiratory pigment called hemolymph. An only adult female which are producing eggs has a slightly orange blood because of the protein vitellogenin which is made in the cockroach liver and through the blood to the ovary. Heart of cockroaches is a pulsatile, 13-chambered structure. It is present below the tergal plates and formally in the thorax and abdomen. Its inhalent openings are called ostia, which are guarded by valves. This heart is, in fact, the dorsal blood vessels, which pulsates with the help of external salary muscles. On the dorsal side of the heart, two nerve chain is present. They work as a pacemaker and start a heartbeat. Such a heartbeat is called a neurogenic heart. The blood in heart flows unidirectionally from posterior end to the anterior end of the body. The hemolymph consisting of a clear colorless plasma rich in amino acids, uric acid, and numerous different cell types called hemocytes.