Cuticular Modification of Nematode

Bursa:

The Bursa/Copulatory Bursa is the large expansion of the cuticle of the male tail to form the clasping organ. The bursa arised form caudal alae. Bursa found in Bursate nematode. It serves to hold onto or to grasp the female during mating. It is composed of fingerlike projection (Bursal rays) separated by thin membranous alae.

Alae:

The alae is a lateral flattened cuticular expansion or wing like protrusions from cuticle. Two types of alae is found.

1. Cervical/lateral alae: on oesophageal region

e.g. Toxocara cati (Arrow Headed worm)

2. Caudal alae: on tail region

Vesicles:

Vesicles are the inflation of the cuticle around the mouth openings and in oesophageal region. Two types of vesicles are found:

1. Cephalic Vesicle,
2. Cervical Vesicle e.g. Oesophagostomum sp

Ø       Several adhesive structures may be found formed from cuticle

                                            i.            Hooks e.g. Tetrameres sp. (male and female)

                                          ii.            Thickening e.g. Gongylonema sp.

                                        iii.            Cephalic collars e.g. Physaloptera sp.

                                        iv.            Alae

Ø  The cuticle covers the external surface and lines buccal cavity, oesophagus, vagina, rectum excretory pores

Ø  The cuticle is protective barrier to enzymes. It is metabolically active.

Ø  The body is unsegmented but the cuticle is annulated (not visible in naked eyes)

Ø  The body wall has three layers: cuticle, hypodermis and an inner layer of muscle cells. The hypodermis, lying beneath the cuticle, is relatively thin and is a syncytium of cells in the majority of nematodes of veterinary importance. The primary function of the hypodermis is to secrete the cuticle

Ø  Muscular Layer: The Muscle cells arranged longitudinally lie between the Hypoermis (i.e. under and the body cavity). The muscular layer is divided into 4 Quadrants by the 4 longitudinal lines/cords. The cells contain fluid at a high pressure which maintains the turgidity and shape of the body. Locomotion is effected by undulating waves if muscle contraction and relaxation which alternate on the dorsal and ventral aspects of the worms.

Ø   The cuticle is a thin layer which projects into the body cavity forming or continuing 4 longitudinal thickening /cords called longitudinal lines

§  Two lateral – Which carry Excretory ducts/canals

§  One ventral- Which carry Ventral Nerve

§  One Dorsal- Which carry Dorsal Nerve

Ø  The heads of some nematodes have structures such as

§  The leaf crown: Finger like projection around the mouth. It is sensory papillae

§  A Buccal cavity

§  Teeth or Cutting Plates

Ø  Most of Internal organs are filamentous and suspended in the fluid filled body cavity

o   Complete Digestive system (Mouth to Anus)

o   With few exception, sexes are separated

o   Life cycle direct or indirect

Papillae:

·         It is the modification of cuticle

·         These are usually spine or hair like but may soft fleshy short.

·         They may occur inside the rim of the mouth opening as internal leaf crown or on the rim itself as external leaf crown. Usually they are found in large Strongylus nematodes.

·         Again, it may be present the oesophageal region (cervical papillae) and near the tail (caudal papillae).