Nematoda & Acanthocephala Flashcards
Class nematoda belongs to phylum:
Nemathelminthes (roundworms)
Class Acanthocephala belongs to phylum:
Acanthocephales
Describe class Acanthocephala:
Thorny-headed worms or spiny-headed worms
Name subclasses of class Nematoda:
Adenophorea
Rhabditida
Strongylida
Ascaridida
Oxyurida
Spirurida
Describe class Nematoda:
Cuticle with circular striations causes pseudosegmentation
Cuticle lines the esophagus and rectum
Epicuticle is a thin layer of lipids and proteins
Hypodermis is a thin layer of tissue immediately underneath the cuticle
Lateral hypodermal cords contains cells and nuclei of hypodermis, and extrude into the pseudocoelom
Dorsal and ventral chords are formed by extensions of the hypodermis
What is the pseudocoelom of Nematoda?
It arises from embryonic blastocoel and is where the lateral hypodermal chords extrude into
Describe the digestive system of Nematoda:
Straight tube consisting of the buccal cavity (stoma, mouth), esophagus, esophago-intestinal valve, intestine and rectum (cloaca in males).
Head region of nematodes is:
adapted to its lifestyle
Different types of nematode oesophageus:
- Rhabditiform
- Strongyliform
- bulb-shaped, large posterior swelling - Filariform
- simple and slightly thickened posteriorly - Trichuroid
- single column of cells (stichosome)
Describe the nervous system of Nematoda:
Consists of:
* Circumesophageal nerve ring
* 2 or 4 longitudinal nerve rings
Anterior, ventral and dorsal nerve trunks
Excretory system of nematodes consist of:
Excretory pores and excretory tubules
Female reproductive system of nematodes:
Oviduct
Receptaculum seminis
Ovary
Uterus
Vulva
Vagina
Eggs
Male reproductive system of nematodes consists of:
Testis
seminal vesicle
Vas deferens
Ejaculatory duct
Cloaca
Spicula
Nematode males are smaller/bigger than females?
Smaller
Which nematode does not reproduce sexually?
Strongyloides
Cuticula of nematode consists of:
Anterior end - cuticle modification:
* Cephalic vesicle
* Cervical vesicle
* Cervical papilla
* Cervical alae
Posterior end - copulatory bursa
* Spicula
* Gubernaculum (guide for spicules)
* Lateral and dorsal lobe
* Bursal rays
* Dorsal ray
* embraces the female during copulation
What are accessory organs in nematodes?
Spicules and gubernaculum
Example of nematoda bursata:
Ancylostomaa
Example of nematoda non-bursata:
Trichuris
Life cycle of nematoda - describe moulting:
4 moulting
Cuticle detach from the hypodermis and is discarded
Types of life cycles for nematodes:
Geohelminthes - direct life cycle
Biohelminths - indirect life cycle with intermediate host
Paratenic parasitism
What is the infective (larval stage) of nematodes?
L3
What are 3 types of nematodes?
Ovipara (eggs placed outside mother’s cavity)
Ovivipara (eggs develop inside the mothers cavity)
Vivipara (offspring is born alive)
Describe the life cycle of Strongyles (fam. Trichostrongylidae)
- Direct
- Eggs are passed with feces, release L1
- Moults to L2 and L3
- L3 is ingested by host with herbage
- L3 enter mucosa of small intestine, caecum or colon
- Moult to L4-L5 - adult
Describe the life cycle of lungworms:
- Indirect
- L1 passed in feces
IH: L2–>L3
Host ingest L3
–> bloodstream –> lung –> L4-L5 in bronchi and trachea
L1 of Trichuris spp. develop inside eggs in:
environment
Genus Toxocara and Toxascaris belongs to order:
Ascaridida
Describe the egg of Toxocara canis
Medium
3 thick shells
Pitted shell
Unembryonated
1 blastomer
Dark brown
Toxocara canis and cati have what migration:
Entero-hepato-pulmonal
Infection of T. canis and cati is by:
Peroral
Transplacental (not T. cati)
Transmammary
Paratenic host
Toxocara is a:
zoonosis
Toxocara causes:
Larva migrans ocularis
Larva migrans cervicalis
Brain and heart leading to death
Ancylostoma braziliensis and N. americanus in human causes:
Dermatitis (larva migrans cutanea)
Name species of order Rhabditida:
Strongyloides stercoralis
Str. westeri
Str. suis (ransomi)
Str. papillosus
Str. fuelleborni
