Cockroach: Digestive and Excretory System NEET Notes | EduRev

Biology Class 11

NEET : Cockroach: Digestive and Excretory System NEET Notes | EduRev

The document Cockroach: Digestive and Excretory System NEET Notes | EduRev is a part of the NEET Course Biology Class 11.
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Cockroach: Digestive and Excretory System NEET Notes | EduRev

(1) Fore gut or stomodaeum :- Ectodermal" :- Formed by the invagination of body wall. Cuticle present in inner side of foregut.

Mouth to - gizzard is foregut

mouth open in the small buccal cavity

Buccal Cavity - opens in tubular pharynx.

Pharynx - open near occipetal for a men in "oesophagus".

In thorax oesophagus expand and called "crop".

Crop opens into thick walled gizzard.

(a) Wall of gizzard - "circular muscle layer" well developed.

(b) cavity of gizzard called - "armarium"

(c) six cuticular teeth occur in cavity. these made up of longitudinal muscle layer and sharp cuticle.

(d) fine grinding of food

(e) cuticular hairs present in the posterior part of gizzard these form "sieve".

(f) Gizzard - grinding in upper part - filteration in lower part.

(2) "Mesenteron" or " Mid gut" (endodermal epithelium)

(a) Anterior Part - Cardia

(b) Gizzard open in cardia by "stomodial valve".

(c) eight small and tubular, finger like blind processes called hepatic caeca, project freely into the heamocoel form the front end of Cardia.

These secrete "digestive juice"

(d) Muscular wall of mesenteron

(e) Inner - circular muscle

Outer - longitudinal muscle, cavity lined by endodermal epitheleum.

(3) "Hind gut or Proctodaeum"

(a) Thin tubules attached at the junction of hind gut and mid gut called "Malpighian tubules". these are excretory organ.

(b) Hind gut - first part - Ileum Its wall is thin and internally folded. Its cuticle bears minute spines, which serve to break the peritrophic membrane.

(c) colon - longest and broader part

(d) Rectum - last part, oval shaped and internally folded wall.

Its wall - 6 folds- called rectal papillae.

These absorb water

(e) Anus :- at the end of 10th abdominal segment.

Salivary gland :-

(a) 1-pair and attached to with oesophagus and occurred in thorax.

(b) Two parts of each salivary gland.

(1) Reservoir part :- cylindrical and storage of saliva.

(2) glandular part:- leaf like, synthesis of saliva occurs in this part.

(c) Common efferent salivary duct arises from both salivary gland.

(d) This duct open in pre-oral cavity at base of hypopharynx.

(e) rings of cuticle occur in wall of duct of salivary gland.

which prevents these tubules from collapsing

Saliva :- "Carbohydrate - digestive enzymes".

ex. Amylase, chitinase cellulase.


(a) Bread, food grain, vegetable, wood , clothes, insects (dead), nymph, moulted exoskeleton.

(b) Identification of food by the help of antenna.

Digestion :-

(a) Start from preoral cavity

(b) saliva - Enzymes of saliva act upon the food till it reaches the crop. Digestion of carbohydrate takes place.

(c) In crop :- Hepatic caeca - Complete digestive juice reaches in crop through the gizzard.

(d) Gizzard :- Food throughly grinded in to a paste by the thick and sharp edged cuticle of internal folds and grooves.

(e) Grinded food enter in to the midgut through stomodial valve.

(f) Wall of Cardia :- A membrane secreted around the food called peritrophic membrane. It is made up of

Glycogen + Protein. It serves to protect the wall of midgut from friction with food particles.

This membrane is permeable to digestive enzyme and digestive food. Bacteria (Trichonympha) present in midgut which are helpful in digestion of cellulase.

(g) Digestion completes in the anterior part of midgut.

(h) Absorption of digested food in the posterior part of mid gut.

Distribution of digested food :- by "heamocoelomic fluid"

Peritrophic membrane and undigested food enter into the Ileum.

Spine - break the peritrophic membrane, so undigested substance release in ileum,

Maximum absorption of H2O occurred in rectum by rectal papilla.


(a) main excretory organ - Malpighian tubules

(b) These associated with Alimentary canal at the junction of midgut and hind gut.

(c) 90-tubules (60-120)

(d) arrange in groups of six to eight and each group have 15 tubules. These are "Ectodermal".

Two part:-

(i) Proximal part - absorptive part

(ii) distal part - secretorypart

(e) wall - cuboidal epithelium with brush border of microvilli

(f) Outer coating of a membrane made up of fibrous connective tissue and muscles.

(g) Pulsation due to muscle, 5-15 pulsation/minute.

(h) Excretory substance enter in to alimentary canal by pulsation.

(i) Distal part of Malpighi tubules collects excretory substance from heamocoel

(j) excretory substance mainly in the form of "potassium Urate"

(k) Potassium urate converted into "Uric Acid" and potassium Bicarbonate by the cells of cuboidal epithelium.

They secrete these substances into cavity of Malpighian tubules.

(l) Reabsorption process occurs in proximal part. All essential materials absorbed and return into heamocoel.
(a) Water absorbed by alimentary canal and excretory materials along with undigested substances excreted outside.

(b) Malpighian are enteronephric and help in osmoregulation

Cockroach: Digestive and Excretory System NEET Notes | EduRev
Absorbs excretory materials from Haemocoel and store in cuticle. Then at the time of moulting excretory substances and cuticle separate out from body.

(iv) Uricose glands - These help in excretion in male cockroach.


(a) "Open types" or "lacunar types" blood filled in blood sinuses.

(b) True blood vessel - absent

(c) largest blood sinus - "haemocoel"

Cockroach: Digestive and Excretory System NEET Notes | EduRev

Blood corpuscles (haematocytes)

(e) "Haematocytes" -

(1) Phagocytosis of bacteria

(2) related with blood clotting.

(f) Blood -

(A) not related with respiration, because respiratory pigment absent.

(B) It works as "hydrolic skeleton ".

(C) Exchange of food, hormones and excretory materials.

two horizontal septa -

(1) Dorsal diaphragm

(2) Ventral diaphragm - these have pores called "fenestrae"

Cockroach: Digestive and Excretory System NEET Notes | EduRev

Diaphragms divides the haemocoel in three chambers i.e.

(1) P.C.S. have heart in dorsal part (Peri cardial sinus)

(2) Middle sinus - P. Visceral sinus has alimentary canal and fat body.

(3) Ventral chamber - Perineural sinus has nerve cord.

Heart of Cockroach :-

(a) divided in to 13 chamber

(b) chamber - inverted funnel like

(c) each chamber connected with P.C.S. by 1-pair of pores, called "Ostia". These pores act as valve.

(d) Blood enters from P.C. Sinus to heart through Ostia.

(e) Each Posterior chamber of heart connected/related with anterior chamber by a valve like pore.

(f) These pore help in flow of blood from posterior to anterior part.

(g) two layer of heart wall

outer layer → fibrous connective tissue

Inner layer → muscular

(h) special type of cells attached with heart wall called "nephrocytes". Functions of nephrocytes.

(i) these controlheart beat.

Heart Beat - 49 heartbeat / mintue

(ii) "storage excretion" storage of excretory substance in the form of "Uric acid.:-

First chamber of heart in the form of long tubule called "anterior aorta" It opens into head sinus.

(j) Beside anterior aorta:- One blood vessel each arises from heart in mesothorax and 3-6 abdominal segments.

(k) These are not true blood vessels because

(a) These are not divided into capillaries

(b) open ends.

(l) 13-pair fan like muscles present in P.C.S. called alary muscles. One end which, is pointed is attached to tergum and other end is broad - connected to dorsal diaphragm. These also fused with heart wall these help in "blood circulation".

(m) Tergosternal muscle also help in blood circulation mainly these concerned with respiration.

(n) "Pulsatile ampulla" present at base of each antennae and base of each wing. pulsatile ampulla helps in blood circulation in antennae and wings.

Passage for blood circulation :-

(a) Diastole phase : From P.V.S. blood goes to paricardial sinus and then by ostia blood enter into heart.

(b) Systole phase - when the heart is filled, it contracts from behind to forward and blood enters in head sinus by anterior aorta.

From head sinus →In neck →"P.N. Sinus" oesophagous prevents flow of blood into P.V. sinus two path of blood flow from P.N.S. to P.V.S. -

(a) By fenestrae

(b) through legs

A vertical septa present in cavity of legs, these septa divide cavity of legs in two chamber:-

Dorsal chamber → Connected with p. visceral sinus

Ventral Chamber → Connected with p. neural sinus


Cockroach: Digestive and Excretory System NEET Notes | EduRev

(1) Respiratory organ - "respiratory tubules"

(2) Network of respiratory tubules in body.

(3) This network open out side the body by the "spiracles"

(4) 10- pair spiracles

2-pair on thorax

1 pair between prothorax and mesothorax

1 pair between mesothorax and metathorax

8-pair on abdomen on first 8 abdominal segment

All spiracles :- on "Pleurone"

(a) First pair of spiracle of abdomen situated on lateral side of "tergum"

(b) each spiracles :- surrounded by a ring shaped sclerites called

"peritreme". Each spiracle is guarded by a valve and bears cilia  like bristles or filtering the incoming air.

(c) Valve absent in 1-pair spiracles of thorax and abdomen both.

(d) each spiracles open into chamber called "atrium" or tracheal chamber.

(e) The tracheal chambers are connected with several main tracheal trunks which repeatedely branch in to a diffuse network of small trachea.

(f) last branches of trachea called "Tracheal Capillaries" or "tracheoles"

(g) Tracheal capillaries - "Intra - cellular"

(h) Tracheal capillaries closed in a cell called "tracheal end cell."

(i) Long process found in tracheal end cell.

(j) These process deeply merge in tissues of body

(k) Each cell of body is directly in contact with processes, blood does not related with respiration in blood respiratory pigment absent.

(l) During day time - cockroach is less active so osmotic pressure of tissue fluid - low

(m) Tissue fluid rises into tracheoles

(n) exchange of gases during day time by the tissue fluid.

(o) Cockroach is more active in night so O.P. of tissue fluid high so tissue fluid do not enter into tracheoles.

(p) Direct exchange of gases take place


Respiratory tubules:-
(A) Spiral rings of chitin occur in the wall of respiratory tubules.they prevent Collapsing.
spiral rings also called "Tenidia".
(B) spiral rings absent in tracheal capillaries.

Breathing :-
(a) Several tergosternal muscles extend between the tergites and sternites of all abdominal segments.

(b) When the abdomen expands, atmospheric air gets filled in the tracheal system through spiracles. This is inspiration.

(c) When the abdomen contracts, the air is forced out. This is expiration.

expiration takes place through first pairs of spiracles of thorax and first pairs spiracles of abdomen.

(d) The spiracular valves control and regulate the in and out passages of the air and abdomen.

(e) The cuticle of cockroach is highly permeable to CO2, but not to O2

(f) Most of the CO2 diffuse out from body wall some of CO2 out through spiracles.



Cockroach: Digestive and Excretory System NEET Notes | EduRev

Cockroach: Digestive and Excretory System NEET Notes | EduRev


Three types of nervous system

(1) Central Nervous system:-

(a) Brain ring - It is located in the head around the pharynx, just in front of tentorium.

Its dorsal part is a thick and bilobed supraoesophageal ganglion or "Cerebral ganglion" formed by

fusion of three pairs of cephalic ganglia.

3 pair ganglia
(i) Protocerebrum

(ii) deutocerebrum

(iii) tritocerebrum

Sub-oesophageal ganglion on ventral side of alimentary canal. Sub oesophageal ganglion formed by the fusion
of three pairs of ganglia.

Both ganglia connected to each other by circumoesophageal connective.

(2) Ventral Nerve Cord :- double solid and ladder like.

Nerve cord has nine segmental ganglia. i.e. Three large ganglia in thorax and six in abdomen. Last ganglion is
located in 7th abdominal segment.

All ganglia formed in embryo stage by the fusion of 2-ganglia. last segmental ganglion formed by fusion of
many ganglia.

"Peripheral Nervous System"

(1) "3-pair of Nerve :- from cerebral ganglion

One pair from protocerebrum - supply-compound eye

One pair deutocerebrum - in antennae

One pair tritocerebrum - in labrum

(2) Three pairs of nerves connect the suboesophageal ganglion with mandibles, maxillae and labium and other
parts of the head and neck.

(3) Six pairs of nerves from prothoracic and five pairs from each of the mesothoracic and metathoracic ganglia innervate different parts of their respective segments.

(4) A single pair of nerves arises from each of the first five abdominal ganglia to innervate muscles, spiracles, heart chambers and other parts in their respective segments.

(5) From the last abdominal ganglion three pairs of nerve arise.
Cockroach: Digestive and Excretory System NEET Notes | EduRev
(3) "Autonomous System"

It is divisible into three parts :-

(1) Stomogastric nervous system :- this includes the following five ganglia they all are inter connected with each other by nerves and the nerves arising from these ganglion to innervate the anterior part of gut, as follows this system regulates involuntary activities of foregut.

(a) Frontal ganglion - This is a small median ganglion located dorsally upon the pharynx just in front of brain.

(b) Hypocerebral ganglion - This is also a small median ganglion located dorsally upon oesophagous behind the brain.

It is also connected, by means of two pairs of fine connectives, with two pairs of adjacent endocrine glands.

glands named -

(i) corpora allata

(ii) Corpora cardiac

All three form "retrocerebral complex" (Hypocerebral ganglion + corpora Cardiaca and Corpora allata)

(c) Visceral ganglion:- This is located mid-dorsally upon the crop at about its middle.

(d) Proven tricular ganglia" (last ganglia)

these are two small ganglia, one upon dorsal and the other upon ventral surface of gizzard. Each of these are connected with visceral ganglion by nerve.

These regulate the activity of foregutas"peristalsis"

(2) Spiracular nervous system :-

(a) This controls the activities of spiracles.

(b) A nerve plexus found around the each spiracle. These are connected with segmental ganglia of nerve chord.

(c) These regulate the activity of spiracle.

(3) "Caudal nervous system"

(a) regulates the activity of hindgut, gonads and abdominal appendages

(b) This nervous system formed by the last segmental ganglion of nerve chord.(7th)

(c) This includes certain fine nerves that arise from the last abdominal ganglion and innervate various parts.

Endocrine glands

(I) Inter cerebral endocrine cells - These cells found in cerebral ganglia and secrete to brain hormone.

It regulates the activity of prothorasic gland.

(II) "Corpora cardiaca" It secretes growth hormone in childhood to control the growth of nymph. In adult stage
these gland regulate heart beat.

(III) "Corpora - allata :-

(a) These glands secrete Juvenile hormone - "neotinin" in childhood stage.

(b) Neotinin regulates the growth and differentiation of tissues, preventing ultimately moulting and metamorphosis.

(c) These glands secrete "gonadotropic" hormone in adult stage - It regulate the activity of reproductive

(IV) Prothorasic gland :-

(a) found only in nymph stage

(b) Secretion of ecdyson hormone in nymph - moulting hormone this hormone induce moulting.

Compound Eyes.

Cockroach: Digestive and Excretory System NEET Notes | EduRev

(1) Compound eye made up of 2000 units called spommatidia.

(2) Outer part of ommatidia - hexagonal lens or "corneal lens " which is formed of transparent cuticle.

(3) Just beneath each lens 2 small cells called "corneagen cells"

(4) These secrete lens

(5) At the time of moulting lens also shed from body so cockroach becomes blind for some time

(6) Corneagen cell - secretion of a new lens.

(7) Beneath these cells is a crystalline cone formed by four surrounding conical cells (- vitrellaor conecells)

(8) Crystalline cone - serves as an accessory lens

(9) part of spommatidia up to cone cell known as dioptric part or focusing part.

(10) Beneath the crystalline cone there is a circle of seven cells called "retinular cells"

(11) The inner border of each retinular cell bears microvilli.

(12) The microvilli of the seven rhabdomeres inter digitate to form a long narrow refractile structure called "rhabdome"

(13) Image formed on rhabdome

(14) Region of retinular cells is called receptor region.

(15) A nerve fibres arises from each retinular cell. All nerve fibers of a compound eye together form"optic nerve".

(16) These nerves supply protocerebrum of cerebral ganglion.

(17) Ommatidium surrounded by a "pigmented sheath"

Two Parts

Upper part - irish pigment sheath
Lower Part - retinular pigment sheath

(18) Pigment sheath seperate omatidia from each other

(19) These prevent the light rays entering into one ommatidium from crossing over to the adjacent ommatidia.

Mechanism :- two types of vision
(1) Apposition or mosaic vision :-

Cockroach: Digestive and Excretory System NEET Notes | EduRev

(a) Apposition vision form in bright light

(b) Omatidia fully covered by pigmented membrane.
The light rays reflected from an object enter in to a number of ommatidia.

(c) An oblique light ray, that enters into the focussing part of an ommatidium, strikes against its pigment sheath and becomes absorbed

(d) A straight light ray that enters into an ommatidium on the other hand reaches into its receptor region and forms the image of corresponding part of the object.

(e) Thus all the straight light rays entering into an eye from an object form separate images of different parts of the object in the different ommatidia.

(f) The totality of these small image is, however, a compound image of the whole object such an image is called apposition image, It is clear and detailed

(2) "Superposition image" :-

Cockroach: Digestive and Excretory System NEET Notes | EduRev
(a) In dim light in nocturnal insects.

(b) In the night, the pigment sheath of ommatidia contracts and shrinks to their bases, hence the light rays can easily cross over from one ommatidium to adjacent ommatidia
(c) complete images are formed in all ommatidia. This results in the formation of blurred superposition of the objects. In cockroach only apposition images are formed (day and night)

No contraction power in pigmented sheath.


Parental Care does not found in Cockroach

Cannibalism - if food is not available, then own species eaten as food.

Cockroach word - originated from Spanish word  "Cucaracha"

Cockroach belong to tropical climate of Africa

Cockroach (Periplaneta) - on 25oC run 130 cm/sec.

Cockroach chromosome no. = 34

Classification :-

Phylum :- Arthropoda

(a) Joined appendages

(b) Blood containing cavity called "haemocoel"

(c) Exoskeleton made up of chitin

Largest phylum :- 90% animals out of total animals belong to this phylum

Class :- Insecta :- largest class

(a) 75% animals included in class Insecta

(b) body divided into head, thorax, abdomen

(c) Three pair of legs (hexapoda )

Subclass :- Pterigota

(a) two pairs of wings

order :- Orthropetra

Wings dissimilar type.

Genus :- Periplaneta americana → "Common Cockroach" or "American cockroach, or Ship cockroach or Bombay canaris.

Blatta (Stylopaga) orientalis

Blatta germanica - smallest cockroach

Male Blatta have wings - female vestigeal wings.

Blatta name - Linnaeus

Periplaneta - "Burmeister"

(a) "Nocturnal animal"

(b) Cursorial animals - fast runner and less capacity of flight.

(c) Body divided in to three parts called "tegmeta".

Cockroach: Digestive and Excretory System NEET Notes | EduRev

some segment fuses in adult stage.

Head 1 (6 segments fused)

Cockroach: Digestive and Excretory System NEET Notes | EduRev

(d) Exoskeleton of chitin plates occurred in each segment. Chitin plate called "sclerites".

(e) Sclerites joined each other by "membrane" called "articular a arthroidal membrane."

Sclerites of dorsal side - tergum or tergite

Sclerites of ventral side - Sternum or sternite

Sclerites of lateral side - pleurons orpleurites.

Head :-

Cockroach: Digestive and Excretory System NEET Notes | EduRev

(a) "Hypognathus Condition ":- Bent downwards at an angle of 900 from the long axis of body.

(b) sclerites of the head joined fully and form head capsule.

(c) Top part of Head is called "Vertex" and on the vertex a chitin plate present called "Occiput".

(d) on the lateral side of head apex 1 pair of compound eye

(e) each compound eye made up of 2000 units called "ommatidia"

(f) A small light coloured spot called fenestra or ocellar spot is located upon dorsal surface close to each eye. In insect it function as a photoreceptor organ. 

In Cockroach - Inactive and called "Vestigial simple eye".

(g) lateral side of head apex bear of 1 pair of antennae.

Main receptor of touch, temperature vibration in cockroach.

Antennae :- long filliform, unbranched. each antenna extending forwards from an antennal socket located dorsally upon head capsule near the compound eye of its side. These are free moving.

(h) A big chitin plate situated below the vertex called frons or forehead.

(i) two long flattened chitin plates situated on lateral side called "gena" or "cheeck"

(j) A big chitin plate present in Anterior part of frons called "Clypeus". a movable chitin plate joined with Anterior part of clypeus known as "labrum" or "Upper lip".

(k) A big pore situated in the ventral part of head called "Occipetal foramen".

(l) Neck joined with head on the "Occipetal foramen.

(m) Occipetal foramen - surrounded by two pair of chitin plate.

Internal :- Post occiput External :- Post gena

(n) A mouth situated in the anterior side of head which is surrounded by many chitinous structure called "mouth parts"

(o) mouth part :- According to food habits.

"Mouth Parts of Cockroach " :- "Bitting and chewing type"

A cavity formed due to mouth parts called "Preoral cavity" or "cibarium".

(1) Labrum or upper lip :- Broad and flattened terminal sclerite of the dorsal side of head capsule moving articulated to the clypeus. It dorsally overhangs the mouth and hence referred to as "upper lip". Several gustatory sensory setae are located on both sides of the indentation.

(2) Mandibles :- Jaw

1-pair of mandibles.

They form the lateral wall of pre-oral cavity. Their Margins towards the mouth are serrated in to three large and a few small, strong and pointed teeth like processes called Denticles.

Horizontal movement occurs in mandibles abductor and adductor muscle associated with mandibles.

A soft structure present base of mandibles called "Prostheca" prostheca have sensory setae.

(3) First maxillae :-

One-pair and form lateral wall of preoral cavity.

Three parts

(1) Protopodite :- articulates maxillae with head capsule

(a) Cardo (b) Stipe

(2) Endopodite :- surrounds preoral cavity laterally.

"lacinia" - inner →spine attached on free end. and help in chewing food outer - Galea

(3) Exopodite :- "maxillary palp"

(a) made up of five segment

(b) first segment joined on stipe called "palpifer"

(c) setae present on maxillary palp sensory for touch, olfactory and gustatory.

(d) With the help of maxillary palp cockroach pickup its food and put it in preoral cavity for chewing.

Maxillary palps also used as brush to clean antenna and wing.

(4) IInd maxillae or "labium"or lower lip.:-

(1) Form floor of preoral cavity

(2) coverventralside.

(3) made up of three flat chitin plate. ie. submentum, mentum, prementum.

(4) All three plates denote "protopodite".

Three pair of appendages joined from prementum

1-pair - labial palps - which joined to prementum with the help of chitin piece called "palpiger". These represent "exopodite". These are 3 segmented structures and have touch, gustatory, olfactory setae.

Cockroach: Digestive and Excretory System NEET Notes | EduRev

Glossa + Para glossa - "ligula"

These are "Endopodite". These prevent outwarding of food from pre oral cavity. labium are one pair in embryo stage. both labium fuses in adult stage.

Hypopharynx :- or "lingua"

This is a small, cylindrical mouth part sandwiched between first maxillae on the sides and covered by labrum and labium respectively on dorsal and ventral sides. It bears several sensory setae at its free end, and the opening of common salivary duct upon its basal part.

Salivarium r Posterior part of ciberium

II segment of head - antennae

III segment of head - labrum

IV segment of head - mandibles

V segment of head - Imaxillae

VI segment of head - IImaxillae(labium)

I segment do not from appendages.

"Neck" - "Soft Neck". or "Cervicum"

8 chitin plates form exo-skeleton of neck.

2- tergum


2 pairs - pleurons.





exoskeleton of each segment made up of

4- chitinplate 1- tergum , 1 sternum and one pair pleurone tergum of thorax - "notum"

Cockroach: Digestive and Excretory System NEET Notes | EduRev

One-pair of legs present in each segment of thorax.

3-pairs of legs(6 legs)

legs - five main segment

(1) segment - "Coxa" :- broadest segment

(2) segment - trochanter :- small segment

(3) - long segment - femur

(4) - tibia - longest segment

(5) - tarsus- tarsus made up of five sub-segments piece of chitin on end segment called "pretarsus" two structure

(1) Arolium or Pulvilus :- These are adhesive pads

(2) One pair claws :- move on the smooth surface by the help of "arolium" and on rough surface with the help of claws.

In Blatta - arolium is absent .

Small pads present in between of tarsus segment called "Plantuli"

Cockroach climb on the wall by the help of plantuli and Arolium.

Tactile setae present on each segment of legs.


Cockroach: Digestive and Excretory System NEET Notes | EduRev

Cockroach: Digestive and Excretory System NEET Notes | EduRev

These called Elytra or Tegmina. wing originate as evagination of body wall and made up of two layers of cuticle.

A network of fine tubules called "nurvures" is present between two layers.

tubules communicate with haemocoel hence, haemocoelmic fluid circulates in these.

These tubules provide nutrition to wings After ageing these tubules dry and provide strength to wings.

Two - pair muscles connected to each wing.

1-pair to tergum

1-pair to sternum

These are called flight muscle. these are not more active in cockroach.


Cockroach: Digestive and Excretory System NEET Notes | EduRev

(3) 7 segment in female remaining segment :- "modified and reduced.

Cockroach: Digestive and Excretory System NEET Notes | EduRev

7th tergum largest in male and female and covers 8th and 9th terga Stink gland present in between 5th and 6th tergum smell - repel the enemies.

10th tergum - bowl shaped and bifurcated. 10th tergam 1 pair - "anal cerci"

Each "anal cerci" - "15 segmented" :- These are main sound receptor.

Sternum - In male - 9 sternum in female - 7 sternum

Projected one-pairs of spine like structure from 9th sternum of male called "analstyles". these are non segmented and help in copulation.

7th sternum of female - special type of boat shaped.

Free end - divided in to two plates

Plates :- "Gynavalvular plates" or "apical lobs".

These plate surround a pore called "ootheca pore"

All characters of sexual dimorphism in cockroach present in abdomen

"ENDOSKELETON" (1) made up of chitin plates called "apodemes". (2) Apodemes formed from invagination of Sclerites. (3) 1-Apodeme in head - Tentorium (Tentorium - Tent like)

Plate like apodems occur in each segment of thorax. Apodemes absent in abdomen.

"Body Wall"

Made up of three layers :-

Cockroach: Digestive and Excretory System NEET Notes | EduRev

outermost- thick cuticle. It is differentiated in to two parts. 

Outer - epicuticlee inner - procuticle

Epicuticle- chitin- absent made up of brown scleroprotein. A waxy layer occurs on epicuticle.

Procuticle :- made up of alternate layer of protein and chitin.

Procuticle :- two parts

(a) Outer - thin (1) exocuticle

(b) Inner - thick (2) endocuticle

Exocuticle :- Attached with protein, and granules of quinones and melanin dark in colour.

Endocuticle :- melanin and quinone - absent, light coloured.

"Epicuticle and exocuticle - discontinuous, absent in joints of sclerites.

Endocuticle :- Continuous, endocuticle become thin in joints and form articular membrane".

2 Hypodermis


(a) made up of columnar epithelium

(b) It contains some special cells.

(i) Dermal gland :- Secretion of chitinase and proteinase enzyme at the time of moulting. They separate old cuticle from body and secrete new cuticle.

(ii) Trichogen cell:- elongated cell and reach up to the epicuticle.

These secrete "sensory setae" on epicuticle.

(iii) Tormogen cell :- long, cup like cell

These cell secrete flexible membrane on the base of setae.

(iv) Neuro - sensory cells :-

(a) These situated in the invagination of tormogen cell. One end of neurosensory cells join setae and other end joined with nerves.

(b) Trichogen + tormogen + neurosensory cell :- All three form sensory unit called "sensilla".

(v) "Oenocytes" :- function - uncertain perhaps these secrete wax on epicuticle

(3) "Inner Most Layer"

"Basement Layer"

(a) "simple squamous epithelium"


(a) called heamocoel

(b) blood filled cavity

(c) blood of cockroach - "haemolymph"

(d) "blood almost colourless 

(e) Blood not related with respiration

(f) Trehalose sugar in blood - disaccharide.


(a) Not true coelom

(b) It is a "large blood sinus"

(c) In embryo stage several small blood sinuses" fuse and form "Large Blood sinus".

(d) All arthropods - "True coelomate" But highly reduced and found only in the form of cavity of gonads".

Cavity of Gonads :- "True Coelom"

(f) large fat body present in haemocoel of cockroach.

(g) analogous to liver of higher animals four types of cells present in fat body :-

(i) Trophocytes :- these store food in the form of glycogen + Protein + Fats.

(ii) Mycetocytes :-

(a) Presence of "Symbiotic bacteria".

(b) These symbiotic bacteria synthesize amino acid and vitamine.

(c) These change glucose in to glycogen (glycogenesis)

(d) Possibly "Uric acid" is converted in protein. this reaction called" reverse-assimilation".

(iii) Oenocytes :- These cells related with metabolism of moulting.

(iv) Urate cell :- Absorption of extretory material from heamocoel and storage in the form of "Uric acid" so called "storage excretion".


Cockroach - "Unisexual"

Male reproduction system:-

(a) 1-pair of testis in "3-6" abdominal segment. each testis formed of "3 or 4 lobes". each lobe divided into many lobules

(b) Vasa deferentia - A vasa deferense arises from each testis these open in an ejaculatory duct.

(c) Ejaculatory duct opens outside by male genital pore.Seminal vesicle in form of vesicles located upon ejaculatory duct.

Cockroach: Digestive and Excretory System NEET Notes | EduRev

(d) A gland associated with seminal vesicles called mushroom gland or utricular gland having two types of tubules, small tubules on inner side- utriculi brevivores.

Large tubules outside - utriculi majors

Tips of long tubules called "Uricose gland"

These absorb excretory material from haemocoel.

(e) A gland located on mushroom gland called phallic gland or congloblate gland. It opens out side by a long duct "Phallic aperture.

(f) Chitinous structures associated with phallic aperture and male genital pore called "phellomeres" or gonapophysis."

Cockroach: Digestive and Excretory System NEET Notes | EduRev
(a) Phallic aperture present on left phellomeres

(b) Male genital pore situated on Ventral phellomeres.

(1) Left phellomeres :-

(1) made up of a flat chitinous plate

(2) four types of lobes attached with it

- lower most lobe titilator, with a hooks on tips

- "Pseudopenis" - long with bulbow apex

- aspirate lobe - lobe of spiny surface, phallic duct opens at the base of asperate lobe

Innermost lobe - "Acutolobe - with a hook

(2) "Right phellomeres" It is a chitinous structure.

Two large hooks present at apex and a hook present on base of right phellomeres.

"Ventral - phellomeres"

(a) simplest and formed of a flat chitinous plate hooks absent. Hooks help in opening of oothecapore of female.

Phellomeres :- "External genital organ"

(a) "Spermatogenesis" "Completely in testis"

(b) Seminal vesicle :- Stored the sperms

(c) All sperms glue together's to form a ball called "sperm ball"

(d) long tubules secrete a membrane around sperm ball called spermatophore

(e) small tubules :- secrete a nutritive fluid in spermatophore.

(f) at the time of copulation spermatophore enters in to ejaculatory duct.

(g) Ejaculaotry duct secrete another coat on spermatophore. spermatophore - "double layered."

(h) when they go out side from male genital pore then phallic gland secretes another layer, so spermatophore becomes three layered.

Female reproductive system

Cockroach: Digestive and Excretory System NEET Notes | EduRev

(1) 1-pair of ovary situated in "2nd to 6th segment of abdomen".

(2) each ovary is made up of 8-long tubules called

"Ovarioles." Only one egg from in each ovariole.

It means 16 ova are matured at a time in cockroach.

Both oviduct of ovaries fuse and form "vagina"

(3) Vagina - vagina opens inside body in a genital chamber.

(4) Genital chamber - formation of genital chamber by  the fusion of 3 abdominal sternum,

(5) 7th sternum - forms the floor of genital chamber.

(6) 8th and 9th sternum - become telescoped inwards to form the roof and sides of this pouch, the pouch itself is divisible into a genital chamber in front and oothecal chamber behind.

(7) A pair of "Spermatheca" associated with genital chamber. 

Spermatheca unequal in size

(8) both spermatheca open by a pore in genital chamber.

(9) A plateform in genital chamber just beneath spermathecapore called "spermatheca Papilla:

(10) 1-pair of collaterial glands associated with genital chamber. These are branched tubular gland"s. left collaterial gland = more branched

(11) Both glands open in genital chamber by a common pore

(12) Three pairs of chitinous processes hanging from the roof of genital chamber into its cavity are the external ganitalia of female cockroach . These are called ovipositor porcesses because these serve to arrange the ova in a newly formed ootheca, and possible help in giving proper shape to the oothecae.


(1) "Breeding season:- from march to september The females secrete a highly odousous and volatile "sex attracting scent from their scent glands called pheromones or ectohormones.

(2) male perceive the smell of this scent with the help of olfactory sensillae located upon their antennae.

(3) male cockroach opens the ootheca pore with the help of hooks.

(4) The male insert whole of its phallomeres into the females's genital pouch. then it inserts its pseudopenis into the female gonopore for firm anchorage.

(5) In this position male genital pore situated on spermathecal papilla

(6) discharge spermatophore by male genital pore upon the spermathecal papilla of female

(7) After that the secretion of its phallic gland upon the spermatophore

Copulation time 1 one hour

(1) The spermatophore remains plastered to the spermathecal papilla of female for about 20 hours. during this period all its sperms escape out and fill in the two spermathecae of the female, then the female drops out the case of empty spermatophore.

(2) Sixteen ova, one from each ovariole of the two ovaries, are dischagred at a time into the genital pouch where these are arranged by the gonapophyses into two parallel row.

(3) Simultaneously, sperms stored in the spermathecae are also discharged into the genital pouch to fertilize the ova.


(a) "Internal fertilization"

(b) After fertilization the left collaterial gland secretes a soluble "milky protein" while the right one secrete dihydroxyphenol.

Both secretions mix to form a brownish scleroprotein.

(c) Sclero protein forms a common egg. case, called ootheca.

(d) formation time - 24 hours

(e) one end of ootheca like a saw and these close the mouth of ootheca

(f) the female deposit it in some dark and dry places.

Development :-
(a) 1 - female form 15-40 ootheca in life time.

(b) Development of egg inside ootheca

(c) Ootheca are adaptation of terrestrial life to prevent the "Water lose"

(d) Development time - "4 to 8" weeks

(e) juvenile stage inside ootheca is called "nymph"

Nymph appear like adult except for wings and reproductive organs

(f) Nymph changes into an adult in - 1 year

(g) During metamorphosis - 7 to 12 times moulting (average - 10 times moulting)

(h) time interval between two moulting called "stadium. 6-11 stadium.

(i) In between moulting nymph called "instar"

Adult insect are called imego"


"Incomplete or paurometabolus"

In insect, those have larva stage have complete or holometabolous metamorphosis.

- "Cleavage" = "superficial meroblastic".

- Gastrulation - "Poly invagination" or "Ingression"

- egg - "megalecithal" and "centrolecithal"

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