The circulatory system of a cockroach is open, and the viscera are immersed in a fluid called haemocoel. This fluid does not assist in respiration, and it is divided into three blood-filled sinuses: the head sinus, pericardial sinus, and perivisceral sinus. The abdominal spiracles are found in the terga and sterna, and are located posteriorly in the abdomen.
The cockroach has separate sexes and displays sexual dimorphism. The male reproductive organs consist of the testes, vasa deferens, and ejaculatory duct. The female reproductive organs consist of the ovaries and the spermathecae. Both are located in the abdominal segments two to six.
The male cockroach has accessory glands located in the sixth and seventh abdominal segments. These glands aid in the development of spermatophores. Both male and female cockroaches have seminal vesicles.
The alimentary canal is long and somewhat coiled and is divided into three segments: the foregut, the middle gut, and the hindgut. The foregut contains six cutical teeth and is bounded by the stomodaeum and mesenteron. The midgut contains eight blind hepatic cae, while the hindgut consists of the ileum, colon, and rectum.
The anus is located on the ventral side of segment 11 and is ventral to the epiproct (tergite 11). Two triangular sclerites flank the anus, which is surrounded by two pairs of paraprocts. The sternites are modified on the ventral side and vestigial.