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Biol 2200 > Nematodas > Flashcards

Nematodas Flashcards

(72 cards)

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1
Q

How are they comapred to mollusca

A

They are species complex

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2
Q

Where are they found and their form

A

Marine
Maiofauna ( biomonitoring)
In parasitic form eg threadworms or pin worms

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3
Q

What are they important for

A

Biomonitoring

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4
Q

What forms can namatode take

A

Parasitic worms the most
Eg. Threadworms and pinworms

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5
Q

How many nematodes yet to be found - diversity

A

3 million per square meter (soil)
Model org - C elegans - free living soil nematodes

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6
Q

Phylum nematode -> Protostome clade-> ecdysozoa

Describe protosomes claded

A

Extraordinary diverse
Ectysozoa - 3 subclass
Divided based on molecular similarities
Some structural too

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7
Q

List the 3 subclasses of ecdysozoa

A

Scalidophota
Panarthropoda
Nematoida

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8
Q

Q- Why are they placed here with the arthropod and not with annelis

A

Shed their Cuticle in order to grow

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9
Q

Characterostocs of nematods

A

T- Triplobastic, bilateral , vermiform, unseg, blastocoelomates / pseudocoelomate (most common)while others are acpelomates
B- cylindrical body
P- pointed at ant and post
C- have a thick , multilayered cuticle
J- juveniles molt
- longitudinal muscles and not cir muscles diff with ANNELIDS
- sense organs - cephalic. Caudal/ohasmids
- no circulatory, resp system
- complete dig system
- Unique secretory -excretory system ( have rennettes cells or set of collecting ducts)
- epidermal is cellular or syncitial, not cilliated
- long epidermal nerve cords
- gonochotistics - many diff modes
- eutely
- free living and parasitic

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10
Q

Describe the pseudocoelom

A
  • gut not lined with cells drived from mesoderm
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11
Q

How are nutrient circulated

A

Diffusion and oasmois

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12
Q

Effects of pesudocoelomate

A

No circular muscles or supporting mesetaries
Organs held loosley and not well developed
No circulation system , therefore through diffusion.

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13
Q

Describe the cuticle of nematode

A

Flexible - you see how it goes wiggly woogly, that also means it is lighter and thinner then mineral skeletons eg bivalves
No cillia , chitin, and emzymes (metabolically active)

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14
Q

Which form need cillia

A

Parasitic forms
Nemotoda lacks cillia

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15
Q

Why are enzymes present on the cuticle

A

Metabolically active

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16
Q

What is the diff btw nematoda and bivalves

A

Thinner and lighter then mineral skelton (bivalaves)

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17
Q

What is absent in the free living form of nematoda?

A

Inner cuticle layer thicker (fibrous layer) in terrestrial and parasitic form
Cilia is also needed in parasitic worm

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18
Q

How is the tegument in trematode & cestode different compared to Cuticle in nematode

A

Cestode (tapewprms) have microtriches and trematode (flukeworms) and nematodes DONT have microtriches

Tegumemt in trematode - made of multiple layers whole tegument is one expended layer , amd syncytial
Tegument in cestode is not multilayered but is syncytial with microtriches
Cuticle in nematode (no tegumemt) is multilayered but not syncytial

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19
Q

What is the imp Cuticle

A

Support
Movement
Prevent drying - cuticle is semipermeables due to the lipids
Role in secretion, excretion and substances uptake

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20
Q

How do nematoda grow

A

Shed by molting (3-4molts - instar to adult)
Controled by hormones
Regularly shed cuticle via excdysis (or molting)
In arthropods - the hormone controll is the ecdysozo, but ecdysozo doesnt control molting in nematoda

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21
Q

How is the outer body look like

A

Can be varied:
Smooth
Sensory setae
Wartlike bump
Ridges
Grooves

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22
Q

Epidermis of nematoda

A

Cellular to syncytial
Thicken sinto ventral, dorsal & lateral longitudinal cords

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23
Q

Muscles in nematoda

A

Have Longitudinal muscles - 4 quadrants
Muscles connected to dorsal and ventral nerval cords by muscle arm rather than nerve extension in the neuron

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24
Q

How is the muscles connection dif compared to other animals

A

Other animals Should have Netve extension in the neuron

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25
Can nematodes use perastaltic burrowing …..
No, they dont have cir muscles
26
Movement in nematodes - how do they move
Have waves of long mus contraction They travel back over the org Propeells the body formward But also They act against the hydrostautic skl and cuticle (imp of cuticle) Free living form - need to have contract in subs to occur
27
Modes of feeding for nematode
Carnivores (plankton, benthic) Deposits Detritivores Microscavengers (feed on fungi &bacteria on dead org or fecal ) Plant parasites of plants - nematodes use stylets Chemautrophic bacterial symbiosis in gut or cuticle ( eg sulfide rich envr)
28
Regional specilization of nematodes
Mouth surr by 6 lips ass with papilae and cuticular flaps Spines, teeth, jaws All these structure are ringly arranged around the mouth itself
29
Nov 29 before feeding and digestion
30
Digestive tract in Nematodes
Buccal cavity -> muscular pharynx (oesophagus) Intestine-> rectum-> cloaca-> trophosome (food storage)
31
Buccal cavity
Many shes and sizes
32
Muscular pharynx
Subdiv into distinct muscular region Function -?
33
Rectum
Subterminal ventral anus
34
Initial and final degestion
Initial - extracellular Final intracellular in intestince
35
K
36
I
37
J
38
K
39
L
40
M
41
Structure for circulation and gas exchanges in nematode
No
42
What are their parasitic forms
Hemoglobin
43
Excretion Do nematode have nephridia ? What do they have instead?
No they dont Rennet cells
44
Function of rennet cells
Connect directly to the excretory pore (anus in females and cloaca in males) only in free living for,s and not parasitic
45
Some groups have lost rennet cells , which forms ?
Parasites (C and D)
46
Kin toprotonephridia cells Osmoregulation
47
Parasitic forms with no rennet cells,what do they have
Protonephridia with no cillia
48
Osmoregulation in nematoda
By rennet cells Outer body the cuticle is deferentially permeable (impermeability due to lipid transfer protein) , allows water in but not out Advantage in a hyper tonic envr Not adv in a hypotonic envr Explanation - more solute outside and less water outside, water want to leave , but cuticle doesnt allow it to leave Vv explanation
49
Nervous system of nematoda
Nerve ring in circle composed of axonal dendrtic processe of neurons Long nerves (dorsal , ventral , lateral) ass to the nerve ring Has lateral commissures that connect all the long nerves Nerve ring also connects to anterior nerves
50
Difference btw nervous system and other organism
Has neuronal cell bodies in a bundle w/0 ganglia bcz no network of nerve fibres but often referrred to as ganglia Body cavity has muscle processes that connect to longitudinal nerve cords instead of the other way around
51
Anteriors nerves function
Have sensory function Leads to sensory structures Sensory str Eg senssilaa - general term for sensory structure eg spine And Labial pappilae Focus on mechanical and chemo sensory function
52
Dorsal cord function - motor
Lateral cord
53
Lateral cord
Sensory but not as well dev as anterior nerves
54
Ventral - main nerve trunk
Sensory and motor
55
Sense organs
Amphids -
56
Amphids function
chemo sensors
57
Amphids are conposed of
Modified cillia
58
Amphids are located in
Lateral part of the head
59
Amphids derived from
Are derived from modified cillia
60
2- phasmids
Posterios Function in chemoreceptor
61
3- sense organ ?
Pigment cup ocelli
62
Reproduction in nematodes
HOGLY DIVERSE MAINLY Gonochoristics With sexual dimorphism Males - smaller and curved Females are larger and straight
63
Males reproductive system in nematoda
Smaller Cloaca Copulatory apparatus - spicule Some have a gubernaculum - guide the spicule into female vagina Pheromones to locate each other + the doagram i made small one in lab
64
Females reproductive system in nematoda
Mid ventral gonoppre separated from anus + the diagram i made in lab
65
Fertilization/copulation
Come together Males wraps curved posteior part around the female gonopore leading into her vagina
66
HIGH REPRODUCTION DIVERSITY of nematodes
hermaphrodite Parthenogenesis Pseudogamy - when the copulate with diff sps sperms that are utilized to start the egg to undergo parthenogenesis (it initiates the egg becoming a zygote ) , BUT NO FERTILIZATION OCCURS Trioery - in a population MANY DIFF REPRODUCTION WAYS OCCURRING
67
What happens (development) after internal fertilization
1- Lay eggs in the envr Zygote with harder egg shell 2- Facultative vivipary - zygote hatches inside uterus - the female doesn’t survive bcz as the zygote grow they feed on mother 3- hermaphrodite (ovotestis)- self fertilization 4- direct development - free living
68
Development in free living forms
1- Direct developmemt after internal fertilization 2- Some have a resistant juvenile stages (dauer stage) - c elegans occurs at when 2nd stage molt into adult Dauer stage helps survive in stress full conditions …..
69
Life cycle and developments in parasitic forms
So,e have a specialized stage i….
70
Whipworm vs roundwarms lifecycle
W- all the dev stages donot occur in the human host Opp in round waorm
71
Whipworm lofe cycle
Mates in human guts Fertilised eggs in host faeces Ingestion of embryos + lifecycle diagram
72
Roundworm life cycle
Complete all stages of dev in human host + diagram

Biol 2200 (1 decks)

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