Question

Describe the alimentary canal of cockroach and its interaction with humankind.

Answer 1

Hint: Alimentary canal is a part of the digestive system, it begins from opening in mount and it opens out positively through anus.
The Foregut of the alimentary canal has crops and gizzard. Crop is used for food storage. Gizzard helps in grinding of food particles. Alimentary canal/gut/ digestive system starts with the mouth and ends with Anus.


Complete answer

The Alimentary canal is also known as Gut. Alimentary canal of cockroach is divided into three regions:
1. Foregut,
2. Mid gut
3. Hind gut.
1. Foregut is composed of mouth, pharynx, esophagus, crop and gizzard. Food is masticated and tasted here
Mouth opens into the tubular pharynx leading to a narrow tubular passage called oesophagus, which in turn opens into a large pyriform sac in the crop. Food is stored in crops. The crop is followed by gizzard which helps in the grinding of food particle foregut is lined by cuticle.
2. Mid gut is composed of Mesenteries and comprises the whole stomach. Mid gut is lined with columnar, glandular epithelium
In midgut a thin peritrophic membrane is formed around the food particle which protects the cellular lining from injury.
A ring of 6-8 blind tubules called hepatic or gastric caeca is present at the junction of foregut and midgut.
3. Hind Gut is a coiled structure which consists of the ileum, colon, and rectum. A ring of yellow coloured thin filamentous malpighian tubules is present here which helps in excretion.
Cockroaches are considered as the most scary creatures because of their looks but it is much more damaging to humankind. Cockroaches feed on a variety of food such as rotten food, dead organisms then later to which they invade fresh food as well. If humans feed on the same food infected by cockroaches then it can cause deadly disease. They can spread disease by carrying disease causing organisms such as bacteria. According to WHO cockroaches can be deadly scavengers as they can cause disease such as allergy, intestinal disease such as cholera, diarrhea etc. They grow in number in poor sanitation conditions where cleaning is not done properly.

Note:Foregut and hindgut are lined by the ectodermal epithelium which secretes cuticles. Mid gut is lined by endodermal epithelium that lacks a cuticle.