BIO2231 Lecture Notes - Lecture 14: Wuchereria Bancrofti, Ascaris Lumbricoides, Worms 2
30 May 2018
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Phylum Nematoda: Roundworms
• Pseudocoelomate, triploblastic, bilateral, eczysozoan
• Digestive system with mouth and anus
• Freshwater, marine, terrestrial
• Epidermis contains NS
• Muscle divided into 4 blocks
• Excretion of ammonia is diffused through body wall
• Only longitudinal muscles-muscle movement is restricted (zig zag like snake)
• Movement only works when against substrate
• Lack cilia
• Pseudocoelom is in high pressure, if cut made on body wall, will explode
• Feeding; detritivores, parasites, predators and microscavengers, piercing mouthparts for
individual cells
• Digestion; specialised gut, cuticle lined pharynx, pumping oesophagus
• Respiration; no special circulatory, have aerobic and anaerobic, require little oxygen
• Parasitic nematodes; Ascaris lumbricoides- live as adults in digestive system, survive very long
in soil, cause blockage
-hookworm- human intestine, suck blood through mucosa, anaemia, teeth
like hook onto wall, suck blood, can cause mental retardation
-filarial worms 1- (wuchereria bancrofti) live in lymphatic system,
can produce elephantiasis
-filarial worms 2- (guinea worm/dracunulus) lives under skin, needs
intermediate, causes severe
burning, causes severe abscess, emerges in water
-filarial worms 3- (onchocerca) causes river blindness, skin of humans,
females produce microfilariae (enters eye then dies)
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