Nematoda

1
Nematoda

• Jenny Brooke David
• Friday, February 15, 2013
• Period 1

http//www.stanford.edu/group/parasites/ParaSites2
006/Loiasis/Home.html
2
Sample Animals and Pictures

• Caenorhabditis elegans
• Tricinella spiralis

David Dallas-Orr
3
Body Cavity (coelom) present or absent

• Have a coelom
• Nutrients are transported in the fluid in the
  pseudocoelom
• The fluid under high pressure

David Dallas-Orr
4
Body Symmetry

• Bilaterally symmetrical

David Dallas-Orr
5
Nervous System

• Nematodes have a reasonably well developed
  nervous system.
• This is comprised of a circum-pharyngeal nerve
  ring made up from 4 nerve ganglia from which 6
  longitudinal nerves extend down through the body
• There are also 6 shorter nerves which extend
  forwards towards the mouth.

David Dallas-Orr
6
Circulatory System

• Lacks a circulatory
• system

David Dallas-Orr
7
Digestive System

• Alimentary canal digestive canal issuing a track
  from mouth to anus

http//classes.seattleu.edu/biology/biol235/hodin/
nematodePriapulidGroup/nematodes/formAndFunction.h
tmexcretory
Pathway of food mouth (stoma) ? pharynx ?
intestines ? rectum ? anus
Jenny Kim
8
Excretory System

• Nitrogenous waste is excreted through body wall
• Rennette gland to excrete salt to maintain
  osmoregulation.

Jenny Kim
9
Locomotion/Musculature

• Only longitudinal muscles for movement
• Moves by undulations or wave-like motions of the
  body. This produces a thrashing movement.

http//classes.seattleu.edu/biology/biol235/hodin/
nematodePriapulidGroup/nematodes/locomotion.htm
Jenny Kim
10
Skeletal Type

• Hydostatic skeleton Non-compressible fluid
  enclosed and pressurized in body cavity.
• Tough cuticle that coats body
• Cylindrical and un-segmented

http//www.newscientist.com/gallery/mg20327161300-
enemy-within-human-parasites/3
Jenny Kim
11
SENSORY STRUCTURES/FEATURES

• Nematodes have peripherally located sense organs.
• Recent studies revealed the presence of true
  cilia in nerve processes connected with sensory
  organs.

• The body is covered in sensory bristles and
  papillae that provide a sense of touch.

http//www.ucmp.berkeley.edu/phyla/ecdysozoa/nemat
oda.html
Brooke Goycochea.
12
REPRODUCTION

• A female may deposit 100,000 or more fertilized
  eggs per day.

• Different species of nematodes have various
  ranges of modes of reproduction.
• Reproduction is usually sexual and most nematode
  species are dioecious.  Some species, however,
  are hermaphroditic.

http//w3.rennes.inra.fr/umrbio3pE/equipes/nematod
es/images/lamelle-460.jpg
Brooke Goycochea.
13
GAS EXCHANGE

• Have an alimentary canal but no circulatory
  system.
• Respiration and gas exchange occur by diffusion
  across the body wall.
• Both anaerobic and aerobic metabolism is common.

http//www.ars-grin.gov/ars/SoAtlantic/fp/stpp/bur
elle/nematode.jpg
Brooke Goycochea.
14
Unique Features of Nematodes

• About 25,000 species are known but about 20 times
  more exist. There is little known about each
  nematode species even though they are numerous.
• It is said that if nothing but nematodes existed,
  they would preserve the outline of Earth and its
  many features.

• Humans host at least 50 nematode species.

http//www.ucmp.berkeley.edu/phyla/ecdysozoa/nemat
odesm.jpg
Brooke Goycochea
15
Quiz

• 1. Which of the following do not have a
  Hydrostatic skeleton for support?
• A. Cnidaria
• B. Platyhelminthes
• C. Nematoda
• D. Annalida

• 2. Which of the following have a circulartory
  system?
• A. Cnidaria
• B. Platyhelminthes
• C. Nematoda
• D. Annalida

• 3. Which of the following does not has a
  different body symmetry in the group listed
  below?
• A. Cnidaria
• B. Mollusca
• C. Nematoda
• D. Chordata

• What type of body symmetry does each of the
  different phyla have? (listed above)

16
Quiz

• 1. Which of the following do not have a
  Hydrostatic skeleton for support?
• A. Cnidaria
• B. Platyhelminthes
• C. Nematoda
• D. Annalida

• 2. Which of the following have a circulartory
  system?
• A. Cnidaria
• B. Platyhelminthes
• C. Nematoda
• D. Annalida

• 3. Which of the following does not has a
  different body symmetry in the group listed
  below?
• A. Cnidaria
• B. Mollusca
• C. Nematoda
• D. Chordata

• What type of body symmetry does each of the
  different phyla have? (listed above)
• A - Radial B,C,D Bilateral

17
Bibliography for beginning pix

• http//riddlelab.msl.ubc.ca/images/maincelegans.jp
  g
• http//images.google.com/imgres?imgurlhttp//work
  force.cup.edu/buckelew/images/Trichinella2520spir
  alis2520male.jpgimgrefurlhttp//workforce.cup.e
  du/buckelew/Trichinella2520spiralis2520male.htm
  usg__-N5OebYUengR9rzBklrnegm5b0Qh512w640sz
  27hlenstart1um1itbs1tbnidTo3n2v9H1z6ALM
  tbnh110tbnw137prev/images3Fq3DTrichinella
  2Bspiralis26um3D126hl3Den26sa3DG26ndsp3D20
  26tbs3Disch1
• http//www.cals.ncsu.edu/course/zo150/mozley/fall/
  nematode.jpg
• http//www.nottingham.ac.uk/bennett-lab/nematode.j
  pg
• http//web.pml.ac.uk/nematode/pictures/images/nema
  tode5.jpg