● The alimentary canal present in the body cavity is divided into three regions: `color{Brown}"foregut, midgut and hindgut"`.

● The mouth opens into a `color{violet}"short tubular pharynx"`, leading to a narrow tubular passage called `color{violet}"oesophagus"`.

● This in turn opens into a `color{violet}"sac like structure"` called `color{Brown}"crop"` used for storing of food.

● The crop is followed by `color{Brown}"gizzard or proventriculus"`.

● It has an outer layer of `color{violet}"thick circular muscles"` and thick inner culicle forming `color{violet}"six highly chitinous plate"` called `color{Brown}"teeth"`.

● Gizzard helps in `color{violet}"grinding the food particles"`.

● The `color{violet}"entire foregu"`t is lined by `color{violet}"cuticle"`.

● A ring of `color{violet}"6-8 blind tubules"` called `color{Brown}"hepatic or gastric caecae"` is present at the junction of foregut and midgut, which `color{violet}"secrete digestive juice"`.

● At the junction of `color{violet}"midgut and hindgut"` is present another ring of `color{violet}"100-150 yellow"` coloured thin filamentous `color{Brown}"Malphigian tubules"`.

● They help in `color{violet}"removal of excretory products"` from haemolymph.

● The `color{violet}"hindgut"` is broader than midgut and is differentiated into `color{Brown}"ileum, colon and rectum"`.

● The rectum opens out through `color{violet}"anus"`.

● `color{violet}"Blood vascular system"` of cockroach is an `color{Brown}"open type"`.

● `color{violet}"Blood vessels"` are `color{violet}"poorly developed"` and open into `color{Brown}"space (haemocoel)"`.

● `color{violet}"Visceral organs"` located in the haemocoel are bathed in `color{Brown}"blood (haemolymph)"`.

● The haemolymph is composed of `color{violet}"colourless plasma"` and `color{violet}"haemocytes"`.

● `color{Brown}"Heart of cockroach"` consists of `color{violet}"elongated muscular tube"` lying along mid dorsal line of thorax and abdomen.

● It is differentiated into `color{Violet}"funnel shaped chambers"` with `color{Brown}"ostia on either side"`.

● `color{Brown}"Blood from sinuses"` `color{Violet}"enter heart through ostia"` and is pumped anteriorly to sinuses again.

● The respiratory system consists of a `color{Brown}"network of trachea"`, that open through `color{Violet}"10 pairs of small holes"` called `color{Brown}"spiracles"` present on the lateral side of the body.

● `color{Violet}"Thin branching tubes"` (tracheal tubes subdivided into tracheoles) carry `color{Violet}"oxygen from the air"` to all the parts.

● The `color{Violet}"opening of the spiracles"` is regulated by the `color{Violet}"sphincters"`.

● Exchange of gases take place at the `color{Violet}"tracheoles by diffusion"`.