Introduction To Nematodes

Front 1

Members of the Phylum Nematoda are collectively referred to as what?

Back 1

Roundworms or Nematodes.

Front 2

2 distingishing characteristic of Nematodes are what?

Back 2

They are bilaterally symmetrical and have a cylindrical shape.

Front 3

Where do Nematodes live and what type of parasites are they?

Back 3

Most are free-living, other nematodes are endopatasites of humans & other animals.

Front 4

Describe the body wall of nematodes.

Back 4

Consists of the following from outside to inside: cuticle, hydrodermis & longitudinal muscles.

Front 5

Describe how the the cuticle of the nematodes body wall produced and what it consists of.

Back 5

It is a noncellular outer covering that is secreted by the hypodermis. It consists of mainly protein collagen, lipoprotein & protein cuticulin.

Front 6

Describe the apperance of the cuticle of nematodes.

Back 6

Often ornamented with pores, punctations, spines & alae.

Front 7

Define pores, punctations, and alae of the cuticle of nematodes.

Back 7

Pores are deep depressions. Punctations are shallow depressions. Alae are lateral or sublateral thickenings and aid in locomotion by increasing the external surface area.

Front 8

Nematodes have a pseudocoel (pseudocoelom) define & describe this body part.

Back 8

A body cavity filled with pink fluid called hemolymph. The fluid is pressurized & functions as a hydrostatic skeleton.

Front 9

How do nematodes move about & why?

Back 9

Nematodes undergo thrashing movements because they only have longitudinal muscles. This is in contrast to flatworms which are segmented & have both circular & longitudinal muscles, thus can crawl.

Front 10

Nematodes have 4 kinds of sensory organs what are they?

Back 10

Papillae, ampids, phasmids, & ocelli.

Front 11

Papillae of nematodes are what?

Back 11

Tactile (touch) receptors & have the appearance of tiny bumps.

Front 12

Amphids of nematodes are what?

Back 12

Pit-like organs. They are more conspicuous in free-living species & are located anteriorly. They function for chemoreceptors.

Front 13

Phasmids of nematodes are what?

Back 13

Pit-like organs near the posterior end of most parasitic nematodes. They function as chemoreceptors.

Front 14

Describe the nematodes digestive system.

Back 14

Typically a complete digestive system w/ a mouth at one end & anus at the other end.

Front 15

Describe the buccal cavity of nematodes.

Back 15

Most species have one. Cutting plates may be present & extend form its wall or maybe on anterior projections of the esophagus. Most species lack cutting plates.

Front 16

If the cuticle of the buccal cavity is very thick what is this rigid structure called.

Back 16

Buccal capsule.

Front 17

Nematodes either have an esophagus or pharynx that function for what?

Back 17

Muscular and function to suck in food & force it into the intestine.

Front 18

Describe the esophagus of Nematodes.

Back 18

Elongated and muscular.

Front 19

Decribe the pharynx of Nematodes.

Back 19

Relatively short and muscular.

Front 20

DOS, 1 or more esophageal bulbs may be present. What are they?

Back 20

Enlargements that are single or posterior bulbs that functions as a 1-way valve to prevent food regurgitation.

Front 21

Describe the intestine of nematodes.

Back 21

Nonmuscular & consists of a single layer of columnar epithelial cells & basement membrans. It is bilaterally flattened when empty.

Front 22

Decribe the function of the intestine of nematodes.

Back 22

Functions for digestion of food & absorption of nutrients. Food rapidly passes through & much of it is not absorbed.

Front 23

Describe the rectum of nematodes, the difference in males & females & it's functions.

Back 23

Both M & F rectums are lined with cuticle & the contents of the intestine pass through these organs. Males rectum is referred to as a cloaca & it also receives sperm from the reproductive system.

Front 24

There are 2 basic types of excretory systems of nematodes. What are they?

Back 24

Tubular kind & Glandular kind.

Front 25

Describe the Tubular kind of excretory system in nematodes.

Back 25

Consists of 2 (sometimes 1) long lateral excretory canals that connect to each other at the anterior end by a transverse canal.

Front 26

Describe the Grandular kind of excretory system in nematodes.

Back 26

Consists of 1 or 2 large cells called renette cells or renette glands.

Front 27

Members of 2 Orders of Nematodes are unique for what reason?

Back 27

They lack an excretory system.

Front 28

Most species of Nematodes are dioecious meaning what?

Back 28

That there are male & female worms.

Front 29

Decribe the male Nematodes.

Back 29

Smaller than females & their posterior end is different than females.

Front 30

What is a bursa?

Back 30

The posterior ends of males are either curled or broadened into a bell-shape or fans-shape structure.

Front 31

What is the function for the different shaped psoterior end of male nematodes?

Back 31

During copulation the posterior end wraps around the female & holds her tightly.

Front 32

Describe the reproduction organs of male nematodes.

Back 32

Tubular shaped & most species only have a single reproductive organ.

Front 33

Describe the sperm of nematodes.

Back 33

They are unique in that they lack a flagellum & move by means of pseudopodia.

Front 34

How does fertilation occur in nemtaodes?

Back 34

Internally & involves copulation. Males have 1 or 2 copulatory spicule(s) which functions to hold open the female genital pore or vulva to allow sperm to pass into her.

Front 35

Describe the reproduction organs of female nematodes.

Back 35

Tubular in shape and most organs are paired.

Front 36

Life cycle of nematodes typically consists of what stages.

Back 36

Adult, egg, 1st stage juvenile, 2nd stage juvenile, 3rd stage juvenile, 4th stage juvenile, adult. Some species the females give birth to juveniles instead of releasing eggs.

Front 37

Describe the juvenile stages of nematodes.

Back 37

All juvenile stages are similar in body form to the adult stage of that species. Each stage sheds its cuticle & becomes the next stage. Growth in body sixe occurs after shedding the cuticle. After the 4th molt in large n ematodes there is a considerable increase in size.

Front 38

Describe the eggs of nematodes and where they hatch.

Back 38

Eggs may or may not have an operculum. Most species the eggs have to be swallowed & typically hatch in the SI of the host. Some species that have a free-living 1st stage juvenile the eggs hatch outside of a host.

Front 39

There are 2 classes of Nematodes of medical importance. What are they?

Back 39

Class Enoplea & Class Rhabditea

Front 40

Describe the Class Enoplea.

Back 40

DOS they have 5 or more esophageal glands that produce salvia. They have the glandular kind of excretory system or lack an excretory system.

Front 41

Describe the Class Rhabditea of Nematodes.

Back 41

They have 3 esophageal glands that produce salvia. They always have the Tubular kind of excretory system. Some may also have the glandular kind in addition.

Front 42

Whipworms belong to what Kingdom, phylum, class and have what SN?

Back 42

Animalia, Nematoda, Enoplea, Trichuris trichiura.

Front 43

Whipworms are parasites to who? What is their distribution?

Back 43

Humans & dogs. Cosmopolitain; common in locals where the climate is warm, humidity & rainfall high & soil retains moisture.

Front 44

What is the common name of Trichuris trichiura and why?

Back 44

Whipworm, because they are shaped like a whip with a handle. The anterior end is long & thread like (buccal cavity & esophagus), the posterior 1/3 is thick (intestine & reproductive organs).

Front 45

Describe the eggs of Whipworms.

Back 45

Barrel shaped with a opercula pug at one end. Pass out of the DH in the feces. The eggs develop in moist shaded soil & become infective in 21 days.

Front 46

Where do the adult worms of Trichuris trichiura inhabit the DH? How do they feed and on what?

Back 46

In the LI, burrow into posterior end (handle part) into the lumen of LI. can live for several years. The buccal cavity has a small stylit & feed on cell contents & blood.

Front 47

The practice of eating soil is called what?

Back 47

Geophagy.

Front 48

S&S of whipworm infection.

Back 48

Most are symptomless. Heavy infection: dysentery (D w/ mucus & blood), anemia, abdominal pain, mental dullness, & growth retardation. Clubbing of the digits or recital prolaps may also occur.

Front 49

What SN & CN species causes Trichoriasis? How is it diagnosed & what is the treatment of choice?

Back 49

Trichuris trichiura, Whipworms. Eggs in feces or colonoscopy reveal adult worms. DOC Mebendazole (Vermox) & Albendazole.