Phylum Nemata (Nematoda)

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Phylum Nemata (Nematoda)
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Phylum Nemata (Nematoda)
Numerous. Wide variety of habitats. Free-living
and parasitic. Pseudocoelomates.
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What do nematodes look like?
Covered with thick cuticle. Epidermis thickened
to house nerve cords and excretory
canals. Obliquely striated longitudinal muscles.
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How do nematodes support themselves and move?
Support comes from cuticle and muscles.
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How do nematodes support themselves and move?
No circular muscles. Pseudocoelom acts as a
hydroskeleton and cuticle used as well.
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How do nematodes support themselves and move?
Cerebral ganglion is a circumesophogeal nerve
ring. Motor and sensory nerves. Tactile papillae.
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How do nematodes feed themselves?
Many feeding modes. Complete digestive
tract. Initial digestion extracellular. Microvilli
in intestine for nutrient uptake,
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How do nematodes circulate nutrients and
osmoregulate?
Pseudocoelom aids in nutrient and gas
exchange. Aerobic and anaerobic
metabolism. Renette cells connect directly to an
excretory pore for osmoregulation and water
removal. Nitrogenous waste lost across intestine.
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How do nematodes reproduce and develop?
Most gonochoristic with sexual dimorphism. Male
thread-like testes. Sperm germinate in distal
end and mature in proximal end near sperm duct.
Travel to seminal vesicle leading to
anus. Females have elongate ovaries widening to
oviducts widening to uteri which lead to vagina
and gonopore.
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How do nematodes reproduce and develop?
Internal fertilization. Zygotes covered in shells
and deposited. Direct development. Holoblastic
cleavage, not spiral or radial. Stereoblastula,
gastrulation by epiboly.
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How do nematodes reproduce and develop?
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How do nematodes reproduce and develop?