Digestive System of Cockroach

Digestive System of Cockroach

1. The alimentary canal is long and somewhat coiled divisible into three main parts namely foregut, midgut and hindgut.
   
2. Foregut (stomadaeum) is differentiated into five parts: Buccal chamber, pharynx, oesophagus, crop and gizzard.
    
3. Gizzard is muscular and internally provided with six cutical teeth which crushes the food.
   
4. A stomodaeal valve is present between gizzard and mesenteron.
   
5. Midgut (mesenteron or ventriculus) is short, tubular lined with glandular endoderm.
   
6. At enterior end of mesenteron there are eight blind glandular hepatic caecae which secrete digestive enzymes.
   
7. Internally mesenteron is not lined by cuticle but it is covered by a very thin and transparent peritrophic membrane formed of chitin and proteins.
   
8. Peritrophic membrane is secreted by gizzard, it serves to protect the wall of midgut from abrasion due to friction of food particles.
   
9. Peritrophic membrane is permeable to digested food and enzymes in the mesenteron.
   
10. Hindgut (proctodaeum) comprises ileum, colon and rectum.
     
11. The wall of rectum is provided with six rectal papillae. They help in the absorption of water and salts.
    
12. Cockroach is omnivorous feeds on all sorts of organic debris.
    
13. The digestive enzymes of saliva are mainly zymase and amylase.
    
14. Most of the nutrients of food are digested in the crop.
    
15. Absorption of digested food takes place in mesenteron.