Introduction to Nematodes Flashcards Preview

VTEC.3100 > Introduction to Nematodes > Flashcards

Flashcards in Introduction to Nematodes Deck (28):
1

Nematoda

All round worms (cylindrical) of animal/human parasitology importance

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Body Morphology

Cylindrical; pseudocoelum
Simple digestive system
Simple excretory system
Simple nervous system
Simple reproductive system

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Cuticle

covering of the body of the worm; should have close-set circular striations; very tough

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Internal leaf crowns

inside rim of mouth opening

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External leaf crowns

on the rim itself

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Cervical papillae

in esophageal region; paired

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Caudal papillae

near the tail; paired

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Prebursal papillae

just anterior to bursa

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cephalic vesicles

cuticle inflated around mouth opening

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Cervical Vesicles

cuticle inflated in the esophageal region

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Alae

flattened expansions of cuticle

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Bursa alae

caudal alae (flattened expansions of cuticle) have become elongated lobes in the male; function in reproduction. Caudal papillae elongated to support them are called bursal rays

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Digestive system of nematode

tubular; floats in fluid-filled body cavity

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Mouth opening of nematode

Called stoma
Can be surrounded by 1) 2-3 lips
2) leaf crowns
Blades, cutting plates, or teeth may be present

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Purpose of knowing esophagus shapes

Shapes help to identify nematodes, especially larvae
(Not commonly done in a typical practice)

16

Filariform (esophagus shape)

simple, posterior diameter slightly greater than anterior diameter

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Rhabditiform (esophagus shape)

anterior and posterior swellings

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Bulb-shaped (esophagus shape)

large posterior swelling

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Double-bulb-shaped (esophagus shape)

bulb constricted behind its middle

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Trichuroid (esophagus shape)

fine lumen; appears to pass through a single column of cells

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Intestine description

simple tube leading from esophagus

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Anus description

usually near the posterior end, has cuticular lining

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Excretory system

Very primitive
Collecting tubules end at mid-ventral excretory pore, in esophageal region

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Female reproductive system

Organs single or double
Ovary, oviduct, uterus, vagina, vulva
Eggs or 1st stage larvae passed from vulva
Some have ovijectors just before vulva that hold and eject eggs
Vulva may be covered by cuticular vulvar flap

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Male Reproductive System

Organs
Testis, vas deferens, seminal vesicle, can have copulatory bursa and spicules (chitinous structures near tail – dilate vulva of female)
Organs
Testis, vas deferens, seminal vesicle, can have copulatory bursa and spicules (chitinous structures near tail – dilate vulva of female)

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Essential Nematode Life Cycle

Egg – In final host
L1
Molt 1
L2
Molt 2
L3
Molt 3
L4
Molt 4
L5 – young adult

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Bursa

a fluid-filled sac or saclike cavity, especially one countering friction at a joint.

28

papillae

a small rounded protuberance on a part or organ of the body.