FINAL - Phylum Nematoda

Question 1

Nematodes are commonly called __________

Answer 1

roundworms

Question 2

2 classes of parasitic nematode

Answer 2

(1) Secernentea (Phasmidia)

2) Adenophora (Aphasmidia

Question 3

Phasmids

Answer 3

small sensory organs, located posteriorly on body surface of secernenteans

Question 4

Most human-infecting nematodes belong to this class:

Answer 4

Secernentea

Question 5

Nematodes characteristics:

Answer 5

elongated, sharply tapered at both ends, uniformly cylindrical (round), bilaterally symmetrical, and possess a pseudocoelom within which all organ systems are found

Question 6

Tube with in a tube:

Answer 6

Outer tube: the body wall and underlying muscles

inner tube: the complete digestive system with an anterior mouth and a posterior anus

Question 7

They are _______ with _________:

Answer 7

dioecious

sexual dimorphism

Question 8

The body wall comprises of the:

Answer 8

cuticle, epidermis and muscles

Question 9

Cuticle

Answer 9

forms the outermost covering of the body

Metabolically active

Question 10

Cuticle surface characteristics

Answer 10

surface may be smooth or non-smooth

structures like bristles, microvilli, spines, warts may be present

Question 11

Cuticle consists of 4 regions:

Answer 11

epicuticle
exocuticle
mesocuticle
endocuticle

Question 12

Hypodermis

Answer 12

lies beneath the basal lamina and secretes the cuticle

Question 13

Muscle types present/absent

Answer 13

Circular muscle is absent

Only longitudinal muscle is present

Question 14

Digestive System

Answer 14

Complete digestive tract with mouth, gut & anus

Question 15

3 major regions of the gut:

Answer 15

fore-, mid-, and hindgut

Question 16

Foregut

Answer 16

begins at the mouth, circular opening and surrounded by lips

Buccal cavity lies between the mouth and esophagus

Has muscles

Question 17

Midgut

Answer 17

aka intestine

simple tube-like

made of 1 layer of cells

With out muscles

Question 18

Junction between fore-& midgut

Answer 18

esophagus-intestinal valve

Question 19

________ serves as the primary means of excretion of ____________, in addition to its function in nutrient ________________

Answer 19

Intestine
waste products
digestion and absorption

Question 20

Hindgut

Answer 20

lies posteriorly. The anus opens to the outside mid-ventrally

Question 21

Excretory System:

Answer 21

Excretion is via renette cells

Question 22

renette cells

Answer 22

unicellular glands that eliminate foreign substances through an excretory pore

Question 23

Male testis:

Answer 23

1 testicle sometimes 2

May be short & uncoiled or long and thread-like

Question 24

Sperm’s pathway:

Answer 24

Testis –> Vas deferens or sperm duct –> seminal vesicle (sperm is stored) –> ejaculatory duct –> cloaca with 2 pouches containing copulatory spicules

Question 25

Females

Answer 25

Didelphic - 2 ovaries (most common)

Monodelphic and polydelphic less common

Question 26

Egg’s pathway:

Answer 26

Ovary –> oviduct –> uterus –> vagina –> vulva

Question 27

Sperm movement

Answer 27

Sperms lack cilia or flagella and move by using pseudopodia

Question 28

Eggs have a shell composed of 3 or 4 layers:

Answer 28

1) vitelline layer
2) chitinous layer
3) lipid layer
4) proteinous layer (in ascaris and trichuris)

Question 29

4 molting stages of larva when hatching form egg:

Answer 29

(1) formation of new cuticle
(2) loosening of the old cuticle
(3) breakage of the old cuticle
(4) escape of the larva

Question 30

Hypobiosis

Answer 30

a lag phase at some stage of development occurs which is an adaptation to withstand unfavorable environmental conditions

Question 31

Larval forms

Answer 31

1st stage: L1

2nd: L2
3rd: L3
4th: L4