Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Parasitology > 10. Nematodes intro > Flashcards

10. Nematodes intro Flashcards

1
Q

nematodes make up what fraction of the multicellular animals on earth?

A

4/5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how many species of nematodes have been described?

A

500,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is a non-parasitic nematode that is used for research and development?

A

Caenorhabditis elegans (C. elegans)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the most common human parasitic nematode worldwide?

A

Acaris lumbricoides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the most common human parasitic nematode in US/Canada?

A

Enterobius vermicularis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

in most species _____ reproduction by adult nematodes is the norm and occurs within an infective definitive host

A

sexual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the ways in which the larval stages may be passed?

A
  • within the egg
  • free living in soil
  • parasitic in an intermediate host
  • parasitic in the definitive host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the basic life cycle of nematodes

A
  • egg
  • four larval stages (L1, L2, L3, and L4)
  • two adult stages comprising separate males and females
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is L5?

A

another name for sexually immature adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the two phases of the life cycle of nematodes?

A
  • pre-parasitic

- parasitic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what stages are part of the pre-parasitic phase?

A
  • L1, L2 and L3

- the parasite must pass through these stages before the nematode is again infective for another host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what stages are part of the parasitic phase?

A
  • L3 and onward

- will undergo a migration within the body of the definitive host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

which nematodes have infectious eggs?

A
  • ascaris (ex: ascaris lumbricoides)

- pinworm (ex: enterobius vermicularis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

which nematode is up to 30 cm in length and lives in the intestines of humans, horses, and pigs?

A

Ascaris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

which nematode spends the entire lifecycle in or on the human host?

A

pinworm/Enterobius vermicularis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

which parasite lays eggs in the perianal region causing itch?

A

pinworm/Enterobius vermicularis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

which nematodes have infectious larvae?

A
  • adult hookworm (Necator americanus)

- trichina worm (Trichinella spiralis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how do the larvae of the hookworm enter the human host?

A

by penetrating skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe the path in the body which is taken by the hookworm?

A

they penetrate the skin, enter the blood stream to travel to the lungs and are coughed up and swallowed in the sputum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the best way to avoid getting hookworm?

A

wearing shoes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the largest nematode and in what animal is it found?

A
  • Placentonema gigantisma
  • 9-13m long
  • found in sperm whales
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

is the body of a nematode segmented or non segmented? flat or round?

A
  • non-segmented

- round (roundworm) and tapered at both ends

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does the nematode body wall consist of?

A
  • an outermost cuticle

- an underlying hypodermis that secretes the cuticle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is the cuticle made of?

A
  • the syncytial hypodermis secretes the thick outer layer of collagen
  • it is proteinaceous (not callagen) with outer lipid laters
25
what are the characteristics of the collagenous cuticle?
- tough | - flexible
26
does a nematodes cuticle have cilia?
no
27
how often is the cuticle molted/shed?
usually four times in the life of the nematode, as it goes through the life stages
28
with which other groups does the nematode share the characteristics of a molted cuticle and the lack of cilia?
- arthropods | - ecdysozoans
29
what constrains the growth of the parasite between life stages?
the cuticle
30
what are the two steps of molting?
- SYNTHESIS of a new cuticle by the hypodermis - EXSHEATHMENT - a process by which the old cuticle is loosened and ruptured followed by the larva wriggling out of the casing
31
what does exsheathment initiate?
infection
32
the process of exsheathment during infection is not only _______ but is also _______ within the host
- host-specific | - site-specific
33
what kind of muscle lies below the hypodermis?
longitudinal muscle (NO circular muscle, meaning the worm cannot shorten and lengthen as do earthworms)
34
movement of the parasite is due to _________ caused by contraction of the longitudinal muscles
undulating motion
35
what type of motion is observed with longitudinal muscle?
dorsoventral flexion, which allows for the characteristic sinusoidal undulating motion
36
what is another name for the body cavity?
pseudocoelom
37
why is it a pseudocoelom and not a coelom?
it is not lined internally with cilia
38
what fills the pseudocoelom?
pseudocoelomic fluid
39
where are reproductive organs found?
suspended in the pseudocoelom
40
what are the two functions of the pseudocoelomic fluid?
- gives the body rigidity | - transports materials from cell to cell
41
is the digestive tract complete or incomplete?
complete
42
what are the parts of the digestive tract in order?
mouth --> pharynx --> oesophagus --> intestine --> anus
43
what is found in the intestine to increase absorption?
microvilli
44
who does most of the digestion, the host or the nematode?
the host, the nematode mostly just absorbed the digested food of the host
45
what does the nervous system of the nematode consist of?
- a ganglian nervous system - with an anterior neural ring, - and 2 or 4 longitudinal nerve truncs extending the length of the nematode
46
what is another name for the anterial neural ring?
circumesophageal ring
47
where is the excretory pore of the nematode?
near the mouth
48
what are the characteristics of the excretory system?
- simple and tubular - one or 2 one-celled renette glands and excretory ducts - excretory pore is anterior - NO flame cells*
49
does the nematode have a respiratory system?
no
50
how does gas exchange occur in nematode?
diffusion
51
all nematodes are ______ (reproductive anatomy)
dioecious (separate male and female organisms)
52
what does the reproductive system consist of?
tubular organs lying in the pseudocoelom
53
what do all nematodes release?
eggs
54
which are smaller, male or female nematodes?
male
55
what is particular about the posterior end of a male nematode?
it is curved
56
what does the male reproductive system consist of?
a single tubules starting with one testis and ending with a terminal cloaca and copulatory spicules
57
what is different in the female reproductive system?
the organs are doubled
58
what are the components of the female reproductive system?
- 2 threadlike ovaries - 2 oviducts - 2 uterus - single genital pore at mid-body
59
what is common about the male and female reproductive organs?
they are both tubular and continuous, and increase in diameter as they extend to the genital opening

Parasitology (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions