SECTION 2 Flashcards by Arriane Cyrel (MTI)

General morphology

Unsegmented, elongated (long) and cylindrical in shape.

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The body is covered by a non-nucleated cuticle which may be smooth striated, bossed or ornamented with spines

General morphology

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body cavity which contains all of the viscera (digestive, excretory, reproductive and nervous system.

Pseudocoele

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mouth/buccal cavity which may be provided with spines, hooks, cutting plates, stylets, or other structures for attachment or penetration

Anterior end

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a few mm to a meter in length

Length

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by sinuous changes of their bodies

Movement

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The (?) are separate, and the females are larger than the males; male posterior end is usually curved

sexes

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testes, vas deferens, seminal vesicle, ejaculatory duct, cloaca

Male

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organs may be single or bifurcated

Female

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a) accessory copulatory apparatus

Male

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(wing-like appendage)

Male

b) gubernaculum

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c) telamon

Male

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d) copulatory spicule

Male

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e) copulatory bursa (umbrella-like ex: Hookworms)

Male

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a) ovary

Female

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b) oviduct

Female

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c) seminal receptacle

female

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d ) uterus

female

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e) ovijector

female

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f) vagina

female

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Oviparous (ex.)

Ascaris

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females will lay eggs, the egg hatches after leaving the host

Oviparous

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Viviparous/Larviparous (ex.)

Trichinella

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– does not lay eggs, but larva

Viviparous/Larviparous

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Parthenogenetic (ex.)

Strongyloides

- female may fertilize herself

Parthenogenetic

- females will lay eggs, the egg hatches before leaving the host

Oviviparous

with complete alimentary tract (pathway of food)

Digestive System

: filariform, rhabditiform, spiruroid, strongyliform or stichosoma

Esophagus

: provided w/ spines, hooks, cutting plates, teeth, etc.

Buccal cavity

with chemoreceptors

Nervous System

- excitatory neurotransmitter (transmits signal)

Acetyl choline

– inhibitory neurotransmitter

Gamma-amino butyric acid (GABA)

- Antihelminthic drug

Gamma-amino butyric acid (GABA)

- Causes paralysis and death of parasite

Gamma-amino butyric acid (GABA)

: pair of laterally placed minute receptor organs in the cephalic or cervical region of all nematodes.

AMPHIDS

: pair of minute lateral post-anal organs in species w/o caudal glands

PHASMIDS

• with collecting tubules or collecting canal & an excretory pore

Excretory System

• fluid of the body cavity contains hemoglobin, glucose, proteins, salts and vitamins

No circulatory system

 Fulfils functions of blood

No circulatory system

1) egg stage 2) four larval stages 3)) adult stage

Developmental stages

Modes of attachment

• Anchorage with attenuated ends (T. trichiura) • Oral attachment to the mucosa (Ancylostoma) • Penetration of the tissues (Strongyloides) - barefoot • Retention in the folds of the mucosa (lumcricoides) – inserts in the foldings of the intestines

- barefoot • Penetration of the tissues (?)

Strongyloides

– inserts in the foldings of the intestines

• Retention in the folds of the mucosa (lumcricoides)

By sucking with ingestion of blood (?)

Ancylostoma - hoowkworm

• By ingestion of lyzed tissues and blood by embedded worms (?)

T. trichiura

• By feeding with intestinal contents (?)

A. lumbricoides

• By deriving from body fluids

. Modes of nourishment

: 4 – 16 weeks

o Trichinella spiralis

: 1 – 2 months

o Enterobius vermicularis

: 12 – 17 months

o A. lumbricoides

: at least 14 years

o Hookworms

: up to 25 years

o Filarial worms

: 5 – 10 years

o T. trichiura

: 20 – 30 years

o S. stercoralis

Life Cycle

o Egg - three layers o Four larval stages o Adult stage

Egg - three layers:

 Vitelline membrane (Ex. Ascaris egg)  Chorionic or true shell  Albuminous covering

: outer membrane (decorticated if without- environmental cause)

Albuminous covering

Aphasmidia Species which parasitize the small intestine

1. Trichinella spiralis 2. Capillaria philippinensis

Phasmidia Species which parasitize the small intestine

1. Ascaris limbricoides 2. Necator americanus 3. Ancylostoma duodenale 4. Ancylostoma ceylanicum 5. Strongyloides stercoralis

Aphasmidia Species which parasitize the large intestine

1. Trichuris trichiura

Phasmidia Specie which parasitize the large intestine

1. Enterobius vermicularis

• Anchorage with attenuated ends (?)

T. trichiura

• Oral attachment to the mucosa (?)

Ancylostoma

• Penetration of the tissues (?)

Strongyloides

• Retention in the folds of the mucosa (?)

lumcricoides

Phasmidia Species which parasitize the tissues

1. Wuchereria bancrofti 2. Brugia malayi 3. Loa loa 4. Dracunculus medinensis

Phasmidia Species which causes larva migrans in man

1. Ancylostima braziliense 2. Ancylostoma caninum 3. Toxocara spp.