Structure of Tapeworm (Taenia): With Diagram

In this article we will discuss about:- 1. Scolex of Taenia 2. Mature Proglottid of Taenia 3. Gravid Proglottid 4. T.S Mature Proglottid 5. T.S. through Gravid Proglottid 6. Cysticercus Larva 7. Cysticercus Larva.

Scolex of Taenia:

1. It is the slide of scolex (head) of Taenia-a tapeworm (cestode) parasite of human beings.

2. It is knob-like and tetra radiate or quadrangular and measures about 1 mm.

3. At its tip is a large aperture the mouth, which is surrounded by two rings of curved and chitinous hooks – the rostellum on are arranged.

4. It is the organ of attachment which through hooks remains embedded in the intestinal mucosa of the host.

5. It bears four large suckers which are arranged along the four corners.

6. The scolex continues behind into a slender neck.

Mature Proglottid of Taenia:

1. It is the slide of a mature proglottid of Taenia.

2. It is enclosed in body-wall which is comprised of a cuticle, a muscular layer and the mesenchyme (parenchyma cells).

3. The mature segment contains male and female reproductive organs, lateral and transverse excretory canals and lateral longitudinal nerves.

4. The male reproductive organs include highly branched testes, vas-deference a highly convoluted vas-deference and a cirrus sac.

5. The female reproductive organs include a pair of ovaries, oviducts, an ootype shell (Mehlis’s) gland, vitelline glana uterus, seminal receptacle, vagina and genital atrium.

6. The common genital atrium facilitates self fertilization. After fertilization the reproductive organs degenerate leaving behind a uterus fully packed with eggs vas-deference and a genital pore. The mature segment transforms into a gravid segment.

Gravid Proglottid of Taenia:

1. It is the slide of gravid proglottid of Taenia a tape worm (Cestode).

2. It is enclosed in body-wall which is comprised of a cuticle, a muscular layer and mesenchyme cells.

3. The whole space in the proglottid s occupied by a highly branched uterus filled with numerous eggs in different stages of development.

4. The male and female reproductive organs & mature segment, have all been degenerated leaving behind only vas-deference and a genital opening as remnants.

5. These gravid segments are shed off, from time to time, from the main chain of proglottids through a process of apolysis.

6. The detached segments escape to out side with faeces of the host.

T. S. Mature Proglottid of Taenia:

1. It is the slide of T. S. of a mature proglottid of Taenia.

2. The outermost covering is body wall which is comprised of a cuticle, a muscular layer and mesenchyme (parenchyma) cells.

3. In the middle region is present a large rectangular uterus filled with eggs and a small rounded and hollow oviduct. On either side of uterus are present numerous structures of various shapes & sizes – the sections of ovary near the lateral ends of the section are present numerous round, oval or irregular solid structures the sections of testes.

4. There is also present a round and hollow excretory canal and a solid longitudinal nerve near the lateral edges.

5. All these structures are surrounded by a band of circular muscles.

T.S. through Gravid Proglottid of a Taenia:

1. It is the slide of T.S. gravid proglottid of Taenia-a tapeworm.

2. The outermost covering is body wall which is comprised of a cuticle, muscular layer and mesenchyme (parenchyma cells).

3. In the middle region are present large number of rounded, oval or irregularpouches-the uterine diverticula filled with eggs.

4. There is also present a rounded and hollow excretory canal and a solid longitudinal nerve near the lateral edge.

5. All the structures are surrounded by band of muscles.

Cysticercus Larva:

1. It is the slide of cysticercus larva (inverted) of Taenia – a tapeworm.

2. It is the second larva in the life history of Taenia and it develops from onchosphere (hexacanth) stage in the muscles of pig.

3. In its transformation to cysticercus stage the onchosphere loses its hooks. The central mass of cells degenerate and thus the whole onchosphere transforms into a hollow bladder. The bladeer enlarges in size and then an inveginaticr’ occurs on one side and develops into a proscolex on which suckers develop through invaginations.

4. The cysticercus bears a scolex, a neck and a bladder-like body.

5. The scolex, like in adult, bears rostellum and four muscular suckers.

6. The rostellum is comprised of two rows of hooks which surround the mouth.

7. The alimentary canal and all other organ- systems are absent.

8. For further development it should be eaten up by man with pork.

Cysticercus Larva of Taenia:

1. It is the slide of cysticercus larva of Taenia-a tapeworm.

2. It is the second larva in the life history of Taenia and it develops from onchosphere (hexacanth) stage in the muscles of pig (intermediate host).

3. The cysticercus possesses a scolex, a neck and a bladder-like body.

4. The scolex, like in adult, bears a rostellum and four muscular suckers.

5. The rostellum is comprised of two rows of hooks and surrounds the mouth.

6. The alimentary canal and other organ- systems are absent.

7. For its further development it should be eaten up by man with pork.