What is the Anatomy of Cockroach?
The explanation of the alimentary canal of a cockroach
The alimentary canal is divided into three parts – foregut, midgut, and hindgut. The mouth opens into the muscular pharynx and follows into the esophagus. The esophagus ends up in a sac-like structure called a crop which is used for storing food. Just beneath the sac, a gizzard or proventriculus is present.
Proventriculus has an outer layer of thick circular muscles and an inner circle made up of 6 chitinous plates which form teeth that functions to break down and grind the food particles. Hepatic caeca or gastric caeca is a ring of 6-8 blind tubules that are present at the junction of the foregut and midgut.
Hepatic caeca are responsible for secreting digestive juices. The midgut and hindgut are long tubules with the hindgut being broader than the midgut. The hindgut is divided into three parts namely, the ileum, colon, and anus. Yellow, thin filamentous rings of 100-150 tubules called Malpighian tubules are present between the midgut and hindgut. Their function is to remove excretory and waste products through hemolymph.
Explain the circulatory system of a cockroach
The open circulatory system is seen with poorly developed blood vessels. The blood vessels open into a space called hemocoel where visceral organs are bathed in blood, thus known as hemolymph. The hemolymph is composed of colorless plasma and hemocytes, thus giving white color to the blood of cockroaches. Lying along the mid-dorsal line of the thorax and abdomen is an elongated muscular tube representing a heart. The heart is further differentiated into funnel-shaped chambers with valves (Ostia) on either side. Blood from the sinuses enters the heart through valves (Ostia) and is pumped out anteriorly to the sinuses again.
Explain the respiratory system of cockroach
Present on the lateral side of the body, there are 10 pairs of holes called spiracles consisting of tracheal tubes. The opening of spiracles is regulated by sphincters. The tracheal tubes are further subdivided into thin branching tubes called tracheoles. These tracheoles carry oxygen from the air to all parts of the body. The exchange of gases takes place at tracheoles by diffusion.