Lecture: Nematodes Flashcards
Adult nematodes are…
unsegmented, elongated, cylindrical worm
All of the viscera including the digestive system, excretory system and the reproductive system are suspended in a body cavity known as
Pseudocele or Pseudocoelum
Fluid of pseudocele
Hemolymph
Esophagus of nematodes that are simple, long and slender; seen in Strongyloides
Filariform
Esophagus of nematodes that is divided into distal corpus, an isthmus and an esophageal bulb; seen in Enterobius
Rhabditiform
Type of nematode esophagus that has an anterior portion muscular, posterior glandular; seen in Filarial worms
Spiruroid
Type of nematode esophagus that is short, muscular with a waist, seen in Ancylostoma
Strongyliform
Type of nematode esophagus that is long, thin, capillary-like lined with esophageal gland cells; seen in Trichuris, Capillaria and Trichinella
Stichosoma
Esophageal gland cells of nematodes
Stichocytes or Stichosomes
Minute inflations of the cuticle, which function as tactile receptors
Papillae
Paired minute chemoreceptor organs located in the cephalic or cervical region of all nematodes are known
Amphids
Pair of minute lateral post anal or caudal chemoreceptor organ present in some species of nematodes without caudal glands is known
Phasmids
Eggs are oviposited and the embryo develops outside the maternal body as in Ascaris, Trichuris
Oviparous
Where the adult female gives birth to a larva as in Trichinella spiralis and Filarial worms
Viviparous or Larviparous
The female can produce viable eggs without being fertilized by the male worms as in Strongyloides stercoralis
Parthenogenetic
Formed immediately after sperm penetration; waxy, colorless and lipoidal in nature
Vitelline membrane
Secretory product of the egg; chitinous in nature and synthesized from glycogen and ovarian nitrogen
Chorionic or True Shell
Outermost layer of the egg; has a tanning action
Albuminous layer
Requires a definitive host but does not require an intermediate host; from the egg stage it develop into the infective stage
Direct or Homogonic
Requires both a definitive host and one or two intermediate hosts for the development into infective stage
Indirect or Heterogenic
Nematodes with only one host are…
Homoxenous
Nematodes with more than one host are…
Heteroxenous
Classification of nematodes without caudal chemoreceptor organ (phasmids) and is provided with caudal glands
Class Enoplea / Class Adenophorea / Class Aphasmidea
Classification of nematodes with caudal chemoreceptor organ (phasmids) and is without caudal glands
Class Rhabditea / Class Secernentia / Class Phasmidea
Nematodes in Class Enoplea
Trichuris trichiura
Trichinella spiralis
Capillaria philippinensis
Nematodes in Class Rhabditea
Ascaris lumbricoides
Strongyloides stercoralis
Enterobius vermicularis
Angiostrongylus cantonensis
Filarial worms
Hookworms
Dracunculus medinensis
Nematodes that inhabits the small intestine
Ascaris lumbricoides
Capillaria philippinensis
Hookworms
Strongyloides stercoralis
Nematodes that inhabits the large intestine
Trichiuris trichiura
Enterobius vermicularis
Nematode that inhabits muscles
Trichinella spiralis
Nematode that inhabits lymphatic system and tissue
Filarial worms
Nematode that inhabits tissue
Dracunculus medinensis
Nematode that inhabits brain
Angiostrongylus cantonensis
Two types of muscle cells in the body wall
Platymarian Muscle Cells
Coelomyarian Muscle Cells
Supporting body wall of nematodes consists of
Outer hyaline, non-cellular cuticle
Subcuticular epithelium or hypodermis
Layer of muscle cell or somatic musculature
Responsible for the secretion of cuticle
Subcuticular epithelium or hypodermis
Outermost layer of the outer hyaline, non-cellular cuticle which is composed of collagen and cuticulin
Cortical Layer
Middle layer of the outer hyaline, non-cellular cuticle
Homogenous Matrix
Inner layer of the outer hyaline, non-cellular cuticle
Fibrous Layer
Constitutes the nerve center for nematodes
Circum-Esophageal Ring Commissure
Oviparous parasites
Ascaris and Trichuris
Viviparous/Larviparous parasites
Trichinella spiralis
Filarial worms
Parthenogenetic parasite
Strongyloides stercolaris