Question

Body cavity of Cockroach is called haemocoel because
A. It contains blood.
B. It contains lymph
C. It is filled with water
D. It is empty

Answer 1

Hint:- Cockroach is a nocturnal insect and is found to tolerate a variety of environments such as from cold Arctic areas to the hotter tropical heat. It belongs to the order Blattodea. It bears a relatively small head with a broad flattened body that is covered by a covering known as an exoskeleton. Most of the species are reddish brown in colour and live in crevices, holes etc.

Complete step-by-step solution:-
The body of the cockroach is narrow, elongated and dorsoventrally compressed. THe body shows bilateral symmetry. The body is covered by a hard waxy covering which can repel water and is known as exoskeleton. The exoskeleton is made up of calcium carbonate and protects the soft internal organs. The body can be divided into three parts which are the head, thorax and abdomen.
The body of cockroaches is coelomate in nature and the coelom is greatly reduced in adults. The spaces present in between the body wall and gut are represented by the haemocoel. The haemocoel is filled with blood. The haemocoel is not a true coelom but it is related to the vascular system. It is divided into three bigger sinuses by two horizontal septa.
The blood vascular system of cockroaches is developed poorly and is of open types. It is also referred to as lacunar type as the blood vessels do not open inside the capillaries rather than directly contact the tissues. This arrangement lowers the rate of circulation. The blood of cockroaches is referred to as hemolymph.
Haemolymph or the blood is the circulating fluid and it is colorless. It consists of many corpuscles and plasma. The corpuscles are known as hemocytes. The haemolymph does not contain any respiratory pigment and does not serve the purpose of respiration. The main function of the haemolymph is transportation of various nutrients from one part of the body to the other. It also plays an important role in the removal of nitrogenous waste products from the tissues to the excretory organs.

Therefore, the correct option is option A.

Note:- In cockroaches, the circulating fluid is the blood or the haemolymph. It is mostly containing cells known as the corpuscles and plasma. The haemolymph is colorless due to the lack of the respiratory pigments. The haemolymph flows between the spaces in between the body wall and the gut which is known as the haemocoel. The haemocoel contains the hemolymph of the blood.