Question

Long answer question:
1. Describe the external morphology of cockroach.
2. Explain the digestive system of cockroach
3. Give an account of the nervous system in cockroach.
4. With the help of neat labelled diagram, explain circulatory system in cockroach
5. Give an account of respiratory system of cockroach.

Answer 1

1. The body of cockroach is divisible into three distinct regions, which are head, thorax & abdomen, a hard exoskeleton made up of chitin is present in the body of a cockroach. Head of the cockroach has a triangular shape, it has compound eyes & antenna protrudes out of it. Thorax is divided into prothorax, mesothorax, & metathorax & each segment has walking legs. The abdomen is made up of 10 segments, the 7th, 8th & 9th sterna form a genital pouch in females, while the genital pouch is present in males at the back of the abdomen.
2. The digestive system is divided into foregut, midgut & hindgut, mouth leads to pharynx which further leads to oesophagus which leads to a sac-like structure called crop. The gizzard is the next structure after crop also called proventriculus, it helps in grinding food. Gastric ceacae secretes digestive juice, Malpighian tubules present at the junction of the midgut & hindgut, help in removal of excretory products through the anus.
3. Circulatory system can be explained by the diagram given above.
4. The respiratory system consists of the trachea which opens through 10 pairs of spiracles present o the lateral side of the body, thin tubes carry oxygen from the air to all parts of the body, they are regulated by sphincters. Exchange of gases occurs through diffusion.