Excretory System of Cockroaches

Cockroaches’ excretory system is in charge of eliminating waste from the body. Malpighian tubules, a pair of coiled tubes that run the length of the cockroach’s body, make up the system. The tubules filter wastes out of the body by collecting them from the blood. The anus is subsequently used to discharge the filtered wastes.

About Excretory System

Uricotelic is a type of cockroach. The structures in cockroaches that aid in excretion are as follows:

(i)Malpighian tubules: Malpighian tubules attach to the midgut and hindgut junction. Excretory products, which are dissolved in haemolymph and absorbed via malpighian tubules,released into the intestines.Each insect has approximately 150 tubules. At least three parts make up each tubule. The short distal area is thinner and more contractile than the rest of the body. The tubule’s central portion, which is made up of primary and stellate cells, takes up the majority of the tubule’s length. Stellate cells feature smaller nuclei, fewer organelles, a simpler brush border, and numerous multivesicular structures than primary cells, which contain numerous refractile mineral concretions. Sometimes symbiont protozoa can be found in the intermediate region’s lumen, around where it enters into the tubule’s proximal part. The latter is a small area that dumps tubular fluid into one of the six ampullae. These are intestine contractile diverticula near the midgut-hindgut junction.

(ii) Fat bodies: Haemocoel contains fat bodies that contain mycetocytes, urate cells, oenocytes, and trophocytes.In the fat body of cockroaches, however, there are two additional types of cells: mycetocytes with an endosymbiont, Blattabacterium cuenoti, and urocytes that deposit uric acid in urate vacuoles. These cells haven’t been investigated in terms of their functions during starvation. The structural alterations in the cells related with starvation in the American cockroach, Periplaneta americana, were originally investigated using light and electron microscopy to obtain insight into the roles of trophocytes, mycetocytes, and urocytes in cockroaches.

(iii) Nephrocytes: The lateral wall of the heart contains nephrocytes, which aid in the excretion and storage of nitrogenous waste.It is made up of a glomerulus, which is where ultrafiltration takes place, and a renal tubule, which is where the filtrate is changed. ‘Nephron-like’ traits may be found in the excretory systems of many invertebrates, raising the possibility that components of the vertebrate excretory system were inherited from their invertebrate ancestors2, despite the fact that it is widely regarded as a vertebrate adaptation1. The glomerular podocyte, a cell in the vertebrate kidney that forms the major size-selective barrier as blood is ultra filtered to generate urine, exhibits striking morphological, molecular, and functional resemblance with the insect nephrocyte.

(iv) Uricose glands: Uricose glands are located on the periphery of mushroom glands in males of some species. Uric acid is produced by these glands. Tubules in Malpighian are similar to tubules in Malpighian.

Respiratory System of Cockroach

• Because blood lacks respiratory pigment, it does not participate in respiration; therefore, every tissue of the body is in direct contact with air for gaseous exchange
• In the haemocoel cavity, a complex system of many, bright, transparent, and branched air tubes called tracheae is discovered for gaseous exchange. Transverse commissures join the six longitudinal tracheal tubes, which are divided into two dorsal, two ventral, and two lateral tubes. Chitinous rings keep the trachea from collapsing
• Atmospheric air enters and exits this system through ten pairs of slit-like holes on the body’s lateral sides called stigmata or spiracles. There are two pairs of thoracic and eight pairs of abdominal muscles
• Spiracles in the thorax are slightly bigger. On respective pleuritis, one pair of them is located between the prothorax and the mesothorax, and the other pair is located between the mesothorax and the metathorax
• The first pair of abdominal spiracles is located dorso-laterally on the tergite of the first abdominal segment, whereas the next seven pairs are located on the pleuritis of the second through eighth segments
• Each spiracle is encircled with peritreme, a ring-like sclerite

Respiration Mechanism

All abdominal segments have several tergo-sternal muscles that run vertically between the tergites and sternites. Harmonious contractions and relaxations at regular intervals create rhythmic expansion and compression of the entire abdomen, resulting in air inhalation and exhalation.

Conclusion

Malpighian tubules, a pair of coiled tubes that run the length of the cockroach’s body, make up the system. The front and posterior sections of the hemipteran digestive system are closely connected in order to bypass most of the midgut and allow the outflow of surplus fluid. 

Primary urine- The waste products of the Malpighian tubules, which are discharged into the hindgut. Stellate cell- Cells that are situated between the Malpighian tubules’ main cells and support them metabolically by managing the movement of ions and water. On respective pleuritis, one pair of them is located between the prothorax and the mesothorax, and the other pair is located between the mesothorax and the metathorax.

 Nephrocytes- The lateral wall of the heart contains nephrocytes, which aid in the excretion and storage of nitrogenous waste. The short distal area is thinner and more contractile than the rest of the body. The proximal part of the tubule and the ampulla are comparable to the midgut in that they have a similar micromal origin and reabsorptive function.