Question

In Periplaneta americana, the blood vascular system is of ____A____type. Blood vessels are____B____. The visceral organs are located in ____C____. ____C____is filled with a fluid which is composed of __D____ and____E___.

• A.

  A	B	C	D	E
  Closed	Absent	Enterocoel	Plasma	Haemocytes

• B.

  A	B	C	D	E
  Open	Poorly developed	Haemocoel	RBC	Haemolymph

• C.

  A	B	C	D	E
  Open	Absent	Haemocoel	Haemocytes	Lymph

• D.

  A	B	C	D	E
  Open	Poorly developed	Haemocoel	Plasma	Haemocytes

Answer 1

Answer: (D)

The circulatory system of cockroach: It is of open type. Blood vessels are poorly developed and open into haemocoel or open spaces. Body fluid present in haemocoel is also known as haemolymph. Blood is colourless as there is no respiratory pigment. Blood doesn't perform the function of transporting gases. The circulatory system consists of heart, aorta, haemocoel and haemolymph. Haemolymph is composed of colourless plasma and haemocytes. Cockroach possesses a 13- chambered tubular, muscular, elongated and neurogenic heart. Blood circulation in cockroach is maintained by wing-shaped alary muscles (involuntary). Each chamber of the heart receives blood from the sinus through 1 pair of slit-like openings called ostia.
The flow of blood can be represented as:
Blood in heart → Pumped into the sinuses → Re-enter the heart by ostia → Again pumped into the sinuses.