Digestive System of Cockroach
NUTRITION
OMNIVOROUS, i.e. It can eat any kind
of organic matter. They search their food by antennae.
TYPE OF DIGESTIVE SYSTEM
TABULAR DIGESTIVE SYSTEM, i.e.
straight slightly coiled dig tube, open at both ends, complete dig. system.
ORGANS OF DIGESTIVE SYSTEM
+ ALIMENTARY CANAL
It is divisible
into 3 parts
1. FORE GUT / STOMODAEUM
§ MOUTH
§ BUCCAL CAVITY
§ OESOPHAGUS
§ CROP
§ GIZZARD
2. MIDGUT / MESENTERON / VENTRICULUS
§ HEPATIC CAECA
3. HIND GUT / PROCTODAEUM
§ ILEUM
§ COLON
§ RECTUM
§ ANUS
+ ASSOCIATED GLAND
§ SALIVARY GLANDS
1.FORE GUT
MOUTH
It lies at base of pre-oval cavity
which is bounded by mouth part.
LABRUM / UPPER LIP
Appendage of 3rd
head segment.
MANDIBLES
Appendage of 4th head segment. They help in mastication
Appendage of 4th head segment. They help in mastication
MAXILLAE
Appendages of 5th head segment. They pick up and bring food.
Appendages of 5th head segment. They pick up and bring food.
LABIUM / LOWER LIP
Appendages of 6th
head segment.
BUCCAL CAVITY
The mouth opens
into buccal cavity which is short and receives the common duct of salivary
glands.
Saliva cantain
‘AMYLASE’ which act upon carbohydrates.
OESOPHAGUS
Buccal cavity opens into pharynx
which in turn opens into oesophagus which is a long and thin tube lying in
thorax.
CROP
It is a large thin walled and pear
shaped structure meant for storing food.
GIZZARD
Crop opens into thick walled, rounded
gizzard with muscular chitins lining which is internally produced six teeth for
grinding and straining the food.
2. MID-GUT
It is narrow, short and tubular
portion originate from gizzard. At beginning it receives eight hepatic caeca
hanging in haemocoel (body cavity filled with white colour blood), ending
blindly but opening in gut.
ENZYMES FROM HEPATIC CAECA
They are lined by
glandular cells, which secrete enzymes.
Enzymes from
hepatic caeca and mid-gut flow back into crop where digestion takes place.
ENZYMES
1. PEDTIDASES AND TRYPSIN LIKE ENZYME -> digest proteins.
1. PEDTIDASES AND TRYPSIN LIKE ENZYME -> digest proteins.
2. AMYLASES ->
complete digestion of starches
3. LIPASE ->
digestion of fats.
Digested food form
a bolus and enclosed in a thin chitinous tube secreted by stomodael valve of
gizzard. This covering is called PERITROPHIC MEMBRANE.
It is permeable to enzymes and digested food. This membrane protects the lining of mid gut from damage by hard indigestible components of food.
Digested food is absorbed in mid gut.
It is permeable to enzymes and digested food. This membrane protects the lining of mid gut from damage by hard indigestible components of food.
Digested food is absorbed in mid gut.
3. HIND-GUT
It has a cuticular ectodermal lining.
ILEUM
Short, narrow and muscular ileum. The
beginning of ileum is marked by 60-70 fine and long, greenish yellow MALPHIGIAN
TUBULES. (excretory in function)
COLON
Colon is long, wider and coiled
portion of hind gut
RECTUM
Rectum is broad last part of hind
gut. It absorbs H2O and conserves the much needed H2O from undigested food
before expelling out the faeces.
ANUS
Anus is the last opening of digestive
system by which hind gut opens to outside.
SALIVARY GLANDS
Salivary glands are 2 in number. each
present on the sides of oesophagus. Saliva contain amylase for digestion of
carbohydrates.
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