Give a brief note on the anatomy of cockroach .

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The adult cockroach has segmented body which is divisible into three distinct regions – head, thorax and abdomen. A hard chitinous brown coloured exoskeleton covered the entire body. In each segment, exoskeleton has hardened plates called sclerites that are joined to each other by a thin and flexible articular membrane.

Anatomical features of cockroach include- alimentary canal, respiratory system, excretory system etc.
1. Alimentary canal: It is divided into: Foregut, midgut and hindgut. ​

• Foregut:

  • Is lined by a cuticle

  • Consists of a mouth which opens into the tubular pharynx, leading into the oesophagus, which further opens into a sac-like crop that stores the food

  • The crop leads to a gizzard (proventriculus). The gizzard helps in grinding food as it has an inner layer with six chitinous teeth.

• The junction of the foregut and midgut has rings of 6 to 8 blind tubules called hepatic or gastric caecae, which secrete digestive juices.

• The hindgut is broader than the midgut, and consists of:

  • Ileum

  • Colon

  • Rectum (opens out through the anus)​

2. Respiratory system: It Consists of a network of trachea, which opens through 10 pairs of small holes called spiracles. Spiracles are present on the lateral side of the body. Opening of the spiracles is regulated by sphincters.Tracheal tubes are subdivided into tracheoles which carry oxygen to all parts. Exchange takes place in the tracheoles by diffusion.

3. Excretory system: Main excretory organs in cockroach are malphigian tubules. These are present at the junction of midgut and hindgut. Nitrogenous waste is converted into uric acid which is excreted out from the body.

4. Circulatory s​ystem: Cockroach has an open type of circulatory system. It has poorly developed blood vessels which open into the haemocoel Organs located in the haemocoel bathed by blood (haemolymph). Heart consists of an elongated muscular tube along the mid-dorsal line of the thorax and the abdomen. It is differentiated into funnel-shaped chambers, with ostia on each side
Flow of Blood: Sinuses → Ostia → Heart → Sinuses

5. Nervous System: It consists of a series of fused segmentally arranged ganglia (joined by paired longitudinal connectives on the ventral side). Three ganglia lie in the thorax and six in the abdomen. It spreads throughout the body, with the head holding just a bit of the nervous system. In the head, the brain is represented by the supra-oesophageal ganglion which supplies nerves to the antennae and the compound eyes.

6. Reproductive system: Cockroaches are unisexual.

• Male reproductive system consists of two testes arising from vas deferens. Seminal vesicles store sperms.
• Female Reproductive System of cockroach consists of  two ovaries. Oviducts of each ovary unite into a single median oviduct (vagina). Vagina opens into the genital chamber. 

Hope this information will clear your doubts about the topic.    Regards