for agriculture students

1. Inner body tube or Digestive
system
HPP-5221 2(1+1)
Nematode pests of horticultural
crops and their management

2. Magnify view of anatomy of
nematode

3. Inner body tube
• The digestive system of nematodes includes the stoma,
oesophagus, intestine and posterior gut. The inner body tube is
divided into 3 main regions.
1. Stomodeum : which constitute the stoma, oesophagus and
cardia.
2. Mesenteron : which constitute the intestine.
3. Proctodeum : which is the posterior –most region comprising
rectum and anal opening.

4. 1. Stomodeum
• Stoma is the portion of the inner body tube lying between the
oral opening and oesophagus. It includes: mouth and lips, the
stoma and the oesophagus
• The stomatal opening is small and slit like and is surrounded
by six lips

5. Mouth and lips
• The and lips are also associated with the feeding activity.
• Generally there are 6 lips which surround the mouth.
• In some cases they may be reduced by partial fusion of 3 or
by complete fusion to form a united ring around the mouth.

6. Stoma or buccal cavity
• Mouth cavity or buccal cavity forms the feeding apparatus
and lie between the mouth and oesophagus.
• Plant parasitic nematodes are armed with a protrusible stylet
which is usually hollow and functions like a hypodermic
needle.
• In, Secernentea, the stylet is thought to be derived from
fusion of the stomatal lining and therefore called as
stomatostylet.

7. Stylet of plant parasitic nematode

8. • The buccal spear is also found in other parasitic as well as
predatory nematodes.
• The stomatostylet is developed from the fusion of the walls of
the buccal cavity.
• In order dorylaimida the stylet arises in two pieces, a buccal
portion, embedded in the oesophageal wall (odontostyle
extension or odontophore) and a replaceable stylet
odontostyle or onchiostyle.
• The replaceable stylet formed within the oesophagus. At each
moult, extension of the cell moves the stylet forward to
displace the old stylet from its basal extension and a new
stylet is formed.

9. Oesophagus or pharynx
• It is the largest part of the Stomodeum and found between
stoma and intestine. The pharynx is mainly a food transporter
pumping food from the low pressure stoma to the high
pressure intestine.
• Internally the pharynx is lined with cuticle and externally by a
membrane (basal lamella). It contains radial muscle,
oesophageal glands and valves, which prevent the
regurgitation of food.

10. Types of oesophagus

11. Types of oesophagi

12. • The oesophago-intestinal valve or cardia is a part of
stomodeum, which lies at the junction of oesophagus and
intestine.
• It controls the passage of food from oesophagus to intestines
in uni-directional flow.

13. 2. Mesenteron or intestine
• The intestine is hollow generally a straight tube formed from
single layer of epithelial cells backed by a well developed
basal lamina.
• In some nematode three distinct region could be distinguished
which are the anterior or ventricular region, the mid
intestinal region and the posterior or prerectal region.
• The plasma membrane which lines the lumen of the intestine is
thrown into fine finger like projection known as microvilli.
They increase the surface area of the intestine and are both
secretary and absorptive in function.

14. Dorylaimid Tylenchid Aphelenchid

15. Microvilli seen on the inner lining
• The intestinal cell is surrounded by a plasma membrane the
whole intestine is separated from the pseudocoelom by a
basement membrane.
• These cells are rich in mitochondria golgicomplex, ER,
ribosome, glycogen, lipid, fatty acid etc.
• The food moves in intestine by the ingestion of more food and
also by the locomotory activity of the nematode

16. 3. Protodeum
• Proctodeum comprises rectum and anus.
• The intestinal tube is connected with a narrow small tube at the
posterior end, through a valve known as rectum.
• It regulates the flow of undigested food material which is to be
passed outside the nematode body through a ventrally located
aperture known as anus.
Anal opening

17. • In male nematode, the rectum joins with the hind part of the
testis forming a common opening known as cloaca. In female,
there is a separate opening.
Glands
• Oesophageal and rectal glands are present in nematodes. The
oesophageal gland enter the stomodeum and rectal gland
enter proctodeum.

18. • Three uninucleated oesophageal glands. One gland on dorsal
and other tow ventro lateral or sub ventral in position. These
gland connect with the lumen of the oesophagus by means of
ducts, often by means of a terminal swelling or ampulla.
• The oesophageal glands have important role in hatching host
penetration and also establishment of host parasitic
relationship.
Rectal glands
• Are responsible for the copious production of gelatinous
mucopolysaccharides matrix in which eggs are deposited as a
mass. It protects the eggs from adverse environmental
conditions.