Sometimes, a human eats a raw or improperly cooked meat. It changes into a fluid-tilled ladder called a cysticercus or bladder warm. (b) Cysticercus: onchosphere forms cyst in the muscles. ![]() Blood carries the larvae to skeletal muscles. Larva bore through the intestinal wall with its hooks and moves into the blood. Digestive enzymes of the cattle free the oncospheres. The cattle graze in pastures contaminated with human feces. (a) Onchosphere: The egg develops and forms a six-hooked larva called onchosphere. It produces about 80, 000 eggs per proglottid. It has two hosts man and cattle (intermediate host). It is medically important tapeworm of humans. Beef Tape worm (Taeniarhynchus saginatus) SOME IMPORTANT TAPEWORM PARASITES OF HUMANSġ. Therefore the adult tapeworms become very long. The proglottids are not continuously lost. Thus the egg is released into the host’s intestine. the uterus opens to the outside of the worm. They pass from the host with the host’s feces. The gravid proglottids break and get free from the end of the tapeworm. Therefore, gravid proglottids are called as “bags of eggs”. Development: The reproductive organs degenerate after storage of egg. Most tapeworms have a blind- ending uterus. This gland helps in the formation of the egg capsule. The ootype is also surrounded by the Mehlis’ gland. The ootype is an expanded region of the oviduct. Then egg passes through the vitelline gland. They fertilize eggs as the eggs move through the oviduct. Sperm are stored in a seminal receptacle. Female reproductive organ: There is a single pair of ovary in each proglottid. Thus cross fertilization produce hybrid vigor.Ģ. Therefore, copulation occurs with another mature proglottlid of the same tapeworm or with another tapeworm in the same host. The male system of a proglottid matures before the female system. These sperms move into the copulatory organ cirrus through a duct system. Male reproductive organs: Numerous testes are scattered throughout the proglottids. Each proglottid contains a complete set of male and female reproductive organs.ġ. A protonephridial system also runs the length of the tapeworm. They extend in the length of the strobila. These nerves arise from a nerve mass in the scolex. The nervous system consists of only a pair of lateral nerve cords. The body systems of tapeworms are reduced in structural complexity except reproductive systems. The tegument even absorbs some of the host’s own enzymes. Therefore tegument plays an important role in nutrient absorption. The outer body wall of tapeworms consists of a tegument. ‘[he proglottids at the posterior end accumulate eggs. They are mature in the mid region of the strobila. The posterior proglottids mature and start producing eggs. The older proglottids are gradually pushed posteriorly. As a tapeworm grows, new proglottids are added in the neck region. Proglottids function primarily as reproductive units. The strobila consists of a series of linearly arranged proglottids. Neck: The scolex narrows to from the neck.ģ. The tapeworm firmly anchors itself to the intestinal wall with the Scolex. It contains circular or leaf like suckers. Their body is divided into three regions.ġ. They show high degree of specialization for parasitic life. The presence of all these structures suggests strong phylogenetic affinities with other cestodes.Īlmost all of the cestodes belong to the subclass Eucestoda. These are not present in an other platyhelminths. Presence or larval stages similar to eestodesģ. Their bodies are not divided into proglottids like other cestodes.īut they also show cestodes characters like:Ģ. Only one set of both male and female reproductive organs are present in it.ģ. ![]() They are all endoparasites in the Intestine and coelom of primitive fishes. So they have evolution from complex to simple. Tape worms have lost many complex structures due to parasitic mode of life. The physiology of the host maintains the homeostasis of tapeworm.Ĥ. Therefore, tapeworms do not required special structures. The adult tapeworms live in a very stable environment. Each proglottid contains a complete set of reproductive Istructures.ģ. The proglottids are a long Iseries of repeating units. Most adult tapeworms consist of proglouids. They absorb nutrients directly from the host.Ģ. Mouth and digestive system is absent in tape worms. Th1 re are following parasitic adaptations in tape worms:ġ. The size of adult tapeworm is from 1 to 23 in in length. They live in the verlebrate digestive system. The members of cestoidae are commonly called tapeworms. It is the most highly specialized class of flatworms.
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