SECTION 2: MORPHOLOGY, PATHOPHYSIOLOGY, LIFE CYCLE, SPECIMENS USED FOR IDENTIFICATION, DIAGNOSTIC FEATURES, PREVENTION & CONTROL OF NEMATODES (ROUNDWORMS)

Question 1

General morphology: (?) in shape.

Answer 1

Unsegmented, elongated and cylindrical

Question 2

The body is covered by a non-nucleated cuticle which may be (?).

Answer 2

smooth striated, bossed or ornamented with spines

Question 3

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

Answer 3

Pseudocoele

Question 4

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

Answer 4

Anterior end

Question 5

– a few mm to a meter in length

Answer 5

Length

Question 6

– by sinuous changes of their bodies

Answer 6

Movement

Question 7

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

Answer 7

larger
curved

Question 8

Reproductive system • Male:

Answer 8

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

Question 9

Reproductive system • Male Parts

Answer 9

a) accessory copulatory apparatus
b) gubernaculum (wing- like appendage)
c) telamon
d) copulatory spicule
e) copulatory bursa (umbrella like ex: Hookworms)

Question 10

: with complete alimentary tract

Answer 10

Digestive System

Question 11

Esophagus:

Answer 11

filariform, rhabditiform, spiruroid, strongyliform or stichosoma

Question 12

: with chemoreceptors

Answer 12

Nervous System

Question 13

• excitatory neurotransmitter

Answer 13

Acetyl choline

Question 14

– inhibitory neurotransmitter

Answer 14

Gamma-amino butyric acid (GABA)

Question 15

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

Answer 15

AMPHIDS

Question 16

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

Answer 16

PHASMIDS

Question 17

: with collecting tubules or collecting canal & an excretory pore

Answer 17

Excretory System

Question 18

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

Answer 18

No circulatory system

Question 19

Developmental stages:

Answer 19

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

Question 20

Reproduction: The adult female may be

Answer 20

a) Oviparous (ex. Ascaris)
b) Viviparous (ex. Trichinella)
c) Parthenogenetic (ex. Strongyloides)

Question 21

a) Oviparous (ex. )
b) Viviparous (ex. )
c) Parthenogenetic (ex. )

Answer 21

Ascaris
Trichinella
Strongyloides

Question 22

Modes of attachment

Answer 22

• 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)

Question 23

• Anchorage with attenuated ends (?)
• Oral attachment to the mucosa (?)
• Penetration of the tissues (?)
• Retention in the folds of the mucosa (?)

Answer 23

T. trichiura
Ancylostoma
Strongyloides
lumcricoides

Question 24

Modes of nourishment

Answer 24

• By sucking with ingestion of blood
• By ingestion of lyzed tissues and blood by embedded worms
• By feeding with intestinal contents
• By deriving from body fluids

Question 25

Life span
o Trichinella spiralis:
o Enterobius vermicularis:
o A. lumbricoides:
o Hookworms:
o Filarial worms:
o T. trichiura:
o S. stercoralis:

Answer 25

4 – 16 weeks
1 – 2 months
12 – 17 months
at least 14 years
up to 25 years
5 – 10 years
20 – 30 years

Question 26

Life Cycle

Answer 26

o Egg
o Four larval stages
o Adult stage

Question 27

Egg - three layers:

Answer 27

Vitelline membrane
Chorionic or true shell
Albuminous covering

Question 28

lack “Phasmids” or without caudal chemoreceptors

Answer 28

Aphasmidia

Question 29

with “Phasmids”

Answer 29

Phasmidia

Question 30

A. Species which parasitize the small intestine Class: Aphasmidia

Answer 30

1. Trichinella spiralis
2. Capillaria philippinensis

Question 31

B. Species which parasitize the large intestine Class: Aphasmidia

Answer 31

1. Trichuris trichiura

Question 32

A. Species which parasitize the small intestine Class: Phasmidia

Answer 32

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

Question 33

B. Specie which parasitize the large intestine Class: Phasmidia

Answer 33

1. Enterobius vermicularis

Question 34

C. Species which parasitize the tissues Class: Phasmidia

Answer 34

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

Question 35

D. Species which causes larva migrans in man Class: Phasmidia

Answer 35

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