10/ Phylum Nematoda (Roundworms) Flashcards

1
Q

Is a large group with 25,000 recorded species (but possibly around 50,000).

A

Phylum Nematoda (roundworms)

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2
Q

The focus of this subject will be more on the common parasitic species of man and animals.

A

Phylum Nematoda (roundworms)

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3
Q

Under phylum that contains a mix both free-living
and parasitic members, classifications will not be included and the parasitic forms will be arranged by type.

A

Nematoda

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4
Q

(nematos) means=

A

'’threads”

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5
Q

Organs are organized enough to form organ-systems.

A

Organ-system grade

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6
Q

Level of complexity of Phylum Nematoda

A

Organ-system grade

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7
Q

Phylum Nematoda includes:

A

Free-living and parasites

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8
Q

Most important parasitic group: causes economic loss in animal and plant-based livelihoods.

A

Phylum Nematoda

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9
Q

Phylum Nematoda has a _____ shape?

A

Cylindrical

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10
Q

Phylum Nematoda has lack of?

A

Lack of motile cilia or flagella (except in one species)

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11
Q

Phylum Nematoda has an embryonic cell layer of?

A

Triploblastic

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12
Q

Anatomy and Physiology of a Nematode:

A

Epidermis
Muscles
Body cavity
Digestion
Nervous System
Reproduction

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13
Q

Thick, noncellular outer
covering made of collagen
o Comes in several layers
o Shed during growth stages
o Has high turgor (strong and
rigid, but flexible) – protects the
worm from hostile environments

A

Cuticle

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14
Q

The underlying
epidermis (also made on syncytial
tegument) that secretes the cuticle

A

Hypodermis

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15
Q

Epidermis:

A

Cuticle
Hypodermis

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16
Q

Complex; Looks more like nerve cells, with the processes contain contractile fibers (actin and myosin)

A

Muscles

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17
Q

Lie beneath the hypodermis.

A

Muscles

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18
Q

Only contract longitudinally, meaning the worm body can lengthen, shorten, and move in a
whip-like manner.

A

Muscles

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19
Q

The lack of circular muscle fibers means the worm body cannot increase/decrease its diameter.

A

Muscles

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20
Q

Body cavity:

A

Pseudocoelomate

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21
Q

Has a body cavity containing the organs, but does not have a structure called the peritoneum which holds organs in place.

A

Pseudocoelomate

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22
Q

Pseudocoelomate – has a body cavity containing the organs, but does not have a structure called the ________- which holds
organs in place.

A

peritoneum

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23
Q

(pseudo) means=

A

“false/fake”

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24
Q

Gut is complete: consists of a mouth, muscular pharynx, long non-muscular intestine, short rectum, and anus.

A

Digestion

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25
Q

Food is sucked into the mouth by contraction of the strong muscles of the pharynx and then pushed down when the muscles relax.

A

Digestion

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26
Q

Intestines is one cell-layer thick and has no muscles, so food matter can only move through intestine by body movements and by additional food being passed into the intestines.

A

Digestion

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27
Q

Digestion is intracellular by phagocytosis of.

A

gastrodermal cells

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28
Q

Is intracellular by phagocytosis of gastrodermal cells

A

Digestion

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29
Q

Nervous System:

A

Sensory Papillae
Amphids
Phasmids

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30
Q

Is a ring of nerve tissue and ganglia around the pharynx, which then gives rise to
2 nerve cords (ventral and dorsal nerve cord) that send signals to the rest of the body.

A

“primitive brain”

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31
Q

Found around head and tail

A

Sensory papillae

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32
Q

Pair of complex sensory organs that open on each
side of the head, which enters into a pore with dendrites.

A

Amphids

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33
Q

Reduced in parasitic nematodes

A

Amphids

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34
Q

Similar to amphids but found in posterior end only found in parasitic nematodes.

A

Phasmids

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35
Q

Reproduction:

A

Copulatory spicules

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36
Q

Most nematodes are dioecious, some monoecious.

A

Reproduction

37
Q

Paired testes, seminal vesicles, vas deferens, spicules

A

Male Reproductive

38
Q

Paired ovaries, paired oviduct, uterus (holds eggs), spermatheca (stores sperms), vagina

A

Female Reproductive

39
Q

Males are smaller than females

A

Reproduction

40
Q

Needle-like mating structures found in posterior end of males to facilitate transfer of sperm.

A

Reproduction

41
Q

Females have a genital pore where sperm is received and eggs are released.

A

Reproduction

42
Q

Nematode sperm is unique because it does not have flagella and is more like an amoeba.

A

Reproduction

43
Q

Fertilization is internal
and eggs stored in uterus until deposition.

A

Reproduction

44
Q

Growth from juvenile to adult is through:

A

molting/shedding of cuticle

45
Q

Life-cycle in parasitic forms may require intermediate hosts
* Many parasitic nematodes have free-living juvenile stages

A

Reproduction

46
Q

Eggs are encased in a highly resistant shell, allowing them to survive in the environment for a long period of time until
conditions are good for them or until they enter their hosts (if parasitic)

A

Reproduction

47
Q

Representative Nematodes are:

A

FREE-LIVING NEMATODE
INTESTINAL ROUNDWORMS
HOOKWORMS
TRICHINA WORM
PINWORM
FILARIAL WORMS

48
Q

FREE-LIVING NEMATODE:

A

Caenorhabditis elegans

49
Q

The most common and well-studied free-living nematode.

A

Caenorhabditis elegans

50
Q
  • Hermaphrodite (only few are males)
A

Caenorhabditis elegans

51
Q

Transparent and almost microscopic

A

Caenorhabditis elegans

52
Q

Caenorhabditis elegans has _________ in intestines.

A

Has gut granules

53
Q

Feeds on bacteria and yeast that develop in decaying organic matter.

A

Caenorhabditis elegans

54
Q

Often large, parasitic nematodes; The worms can only mature and reproduce in
the intestines of their specific host.

A

INTESTINAL ROUNDWORMS

55
Q

The most common nematode parasite in humans (1.27 billion people infected
worldwide
“Large Roundworm of Humans”

A

Ascaris lumbricoides

56
Q

Ascaris lumbricoides
Mode of Transmission: (spread via unsanitary defecation habits and
accidentally ingesting the eggs)

A

Feco-oral

57
Q

looks similar to A.
lumbricoides, but it is spread by pigs (but can also infect humans)

A

Ascarias suum (large roundworm of pigs)

58
Q

Life-cycle similar to Ascaris, but juveniles do not migrate to other organs in the dog and just stay in the digestive tract.

A

Toxocara canis

59
Q

Taxocara canis mode of transmission:

A

Feco-oral

60
Q

Can infect humans, but do not complete life-cycle in the humans.

A

Taxocara canis

61
Q

The juvenile/larval forms will just travel/migrate the body and enter organs called:

A

Visceral larval migrans

62
Q

Intestinal Roundworm of Dogs

A

Taxocara canis

63
Q

Small nematodes; their anterior end curves, giving it a hook-like appearance, only mature in the intestines of their host.

A

HOOKWORMS

64
Q

Their mouth possesses large “teeth” plates to cut the intestinal wall of their hosts and their saliva contains_________ to prevent clotting.

A

Anticoagulant

65
Q

Human hookworm

A

Necator americanus

66
Q

Life cycle:Eggs are shed with feces of infected individual.

A

HOOKWORM

67
Q

Whey they come in contact with bare hands/feet of potential host, the ___________ and enter the bloodstream until they reach the intestines.

A

Larvae penetrates the skin

68
Q

“Canine hookworm”

A

Ancylostoma caninum

69
Q

Similar-cylcd as Necator with freeiving larval stage

A

Ancylostoma caninum

70
Q

Can infect humans, but do not complete life-cycle in the humans. Instead, the juvenile/ larval forms will just continue to migrate through the skin called:

A

Ancylostoma caninum and migrate through the skin called cutaneous larval migrans

71
Q

Small nematodes that tends to curl into a spiral; ovoviviparous (females incubate eggs inside body and “gives birth” larvae.

A

TRICHINA WORMS

72
Q

Larvae forms cysts in tissue and muscles

A

TRICHINA WORMS

73
Q

Trichina worm of pork

A

Trichinella spiralis

74
Q

Mode of transmission in trichinella spiralis:

A

Eating raw/undercooked pork with encysted juveniles

75
Q

No free-living stage. Spends entire life in host.

A

Trichina worm of pork

76
Q

Small intestinal nematodes with a characteristic pointed tail, giving it a “pin-like” appearance.

A

PINWORMS

77
Q

“The human pinworm”

A

Enterobious vermicularis

78
Q

Life cycle: Female pinworms migrate to anus of host at night to lay their eggs on the wall of the anus.

A

Enterobious vermicularis

79
Q

Most common nematode parasite in children

A

Enterobious vermicularis

80
Q

Long, thin nematodes that invades the circulatory and lymphatic system if their host

A

FILARIAL WORMS

81
Q

Long, thin nematodes that invades the circulatory and lymphatic system if their host; their larval form is called____ ingested by mosquitoes where it develops further into its infective larval stage.

A

Microfilaria

82
Q

“Human filarial worm”

A

Human filarial worm

83
Q

Life cycle: humans are infected when bitten by mosquito carrying the infectious larval stage.

A

Wuchereria bancrofti

84
Q

The larga I’ll travel through the circulatory system and enter in the________ to become adults.

A

Lymphatic system

85
Q

Affected parts (usually legs and arms, sometimes testicles in males) in a disease called:

A

Elephantiasis

86
Q

“Canine Heartworm”

A

Dirofilaria immitis

87
Q

Causative agent of Dirofilariasis/Heartworm in dogs

A

Dirofilaria immitis

88
Q

Mode of transmission of Dirofilaria immitis:

A

Bite of mosquitos carrying infectious larva