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A Handbook of Biology

ÇÏRÇÜLÅTØRÝ

SÝSTËM

7

6

It has funnel-shaped chambers with

ostia on either side.

Blood from sinuses enter heart through

ostia and is pumped anteriorly to sinuses

again.

5

4

3

2

1

Blood vascular system: open type.

Blood vessels are poorly developed and

open into space (haemocoel).

Visceral organs located in the haemocoel

are bathed in blood (haemolymph).

Haemolymph = Colourless plasma +

Haemocytes.

Heart consists of elongated muscular

tube lying along mid dorsal line of thorax

and abdomen.

RËSPÏRÅTØRÝ SÝSTËM



It consists of a network of trachea that open through 10 pairs of small

holes called spiracles present on the lateral side of the body.



The thin branches of tracheal tubes are called tracheoles. They carry

oxygen from the air to all parts.



The opening of the spiracles is regulated by sphincters.



Gas exchange takes place at the tracheoles by diffusion.

ËXÇRËTØRÝ SÝSTËM

2

Each tubule is lined by glandular and ciliated cells. They

absorb nitrogenous wastes and convert them into uric acid

which is excreted out through the hindgut.

1

Cockroaches are uricotelic. Excretory organ is Malpighian

tubules.

3

Fat body, nephrocytes & urecose glands also help in excretion.