Compound Eyes of Cockroach:
Location :
The eyes of cockroach are
large, black, kidney-shaped structures situated dorso-laterally on the head.
Structure :
Each eye is
composed of about 2,000 similar hexagoal units, called as ommatidia. Each ommatidium capable of forming image, hence, called compound eyes. Each ommatidium consists of two parts:- diopteric and receptive.
A.Diopteric Part:
It
gathers and focusses
the light rays. It consists of corneal lens
secreted by corneagen
cells
and vitrellae
or cone cells
which forms a hard crystalline
cone
or lens.
B. Receptive Part: It receives the image cells or retinulae and rhadomere forming long refractive rod, the rhabdome.
Function of eye:
An apposition or mosaic image is formed in cockroach.
Walking
leg of Cockroach
In
cockroach there are presence of three pair of walking leg.
Location
:
According to basis of attachment with thorax they are called as pro-thoracic,
meo-thoracic and meta-thoracic
legs.
Structure
:Each
leg consists of following parts.
1. Coxa
2. Trochanter
3. Femure
4. Tibia
5. Tarsus
1.
Coxa :
It is large basal part of leg articulate with thorax segment.
2.
Trochanter: It is small, freely
moving part of leg.
3.
Femur :
It is long, broad and stout part of leg of cockroach.
4.
Tibia :
It is long, slender, and uniformly thick part of leg. Tibia shows presence of
stout bristles.
5.
Tarsus :
It last segment of leg consists of five movable joints or podomere. The
podomere shows presence of adhesive pads, the platulae. The last podomere of
tarsus have pair of claws. In between claws, soft and hollow pulvillus or
arolium is present, act as adhesive organ for holding support on smooth
surface.
Function:
The legs of cockroach are adopted for locomotion, climbing and running.
Cockroaches are able to fast running hence called cursorial.
Gizzard
of Cockroach
 |
| T. S. Of Gizzard of Cockroach |
Location
:Gizzard
is rounded muscular structure lies between fore gut and mid gut.
Structure
: The lumen of gizzard shows
presence of 6 –chitenous teeth in anterior chamber and posterior
part shows ring shaped fine hair-like bristles.
Functions
of gizzard:
1.
The
chitenous teeth helps in grinding of food material.
2.
The
bristles are useful for straining or filter fine particle, entering into the
mid-gut. Thus, bristles act as sieve.
Thoracic
Spiracles of Cockroach
In
cockroach respiration is takes place through spiracles and trachea.
In
cockroach there are ten pairs of
spiracles also called as stigmata.
Location
: Out
of ten pairs of spriacles, two pairs are present in the thorax and eight pairs
of spiracles are present on abdomen.
Structure:
1. Each
spiracles has two parts i.e. cup like atrium covered by lid or operculum.
2. The
thoracic spiracles operculum is bi-lobed
while abdominal spiracles operculum is single, parrot beak like.
3. Each
spiracle has slit like aperture. Opening
and closing of spiracle is regulated by sphincter valves.
4. Each
spiracle is surrounded by bristles, preventing entry of dust particle into
spiracles.
5. The
slit of spiracles leads into short chamber called atrium.
6. From
atrium arises the tracheal tube which leads into tracheoles.
Function:
Inlet
and outlet of air during respiration.
Trachea
of Cockroach
The
respiration in cockroach is takes place by trachea and trachioles.
Location:
Trachea forms transverse and longitudinal network on dorsal, ventral and
lateral side.
Structure
:
Each trachea is tube like structure made up of elastic material covered by
chitinous spring-like lining called as intima. The intima prevents trachea from
collapsing during respiration.
Function:
inhalation and ex-halation of respiratory gases.
Salivary Gland of Cockroach:
Location : In cockroach a pair of salivary gland associated with alimentary canal lies in thoracic cavity on either side crop.
Structure: Each lobe of salivary gland shows two parts
1. Glandular part
2. Bag like reservoir.
From glandular part arise salivary duct which unite to form common salivary duct. The common salivary duct unites to form efferent salivary duct which runs anteriorly and opens at the base of hypo-pharynx in pre-oral cavity. The two ducts of reservoir join to form another common salivary duct.
Functions of salivary gland:
1.
Salivary gland is made of several lobules or acini
produces saliva.
2.
Salivary reservoir stores saliva.
