nematoda jenny brooke david friday, september 04, 2015 period 1
TRANSCRIPT
NematodaJenny Brooke David
Wednesday, April 19, 2023
Period 1
http://www.stanford.edu/group/parasites/ParaSites2006/Loiasis/Home.html
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
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
Digestive System
• Alimentary canal: digestive canal issuing a track from mouth to anus
http://classes.seattleu.edu/biology/biol235/hodin/nematodePriapulidGroup/nematodes/formAndFunction.htm#excretoryPathway of food:
mouth (stoma) pharynx intestines rectum anusJenny Kim
Excretory System
• Nitrogenous waste is excreted through body wall
• Rennette gland to excrete salt to maintain osmoregulation.
Jenny Kim
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
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
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/nematoda.html
Brooke Goycochea.
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/nematodes/images/lamelle-460.jpg
Brooke Goycochea.
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/burelle/nematode.jpg
Brooke Goycochea.
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/nematodesm.jpg
Brooke Goycochea
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)
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
Bibliography for beginning pix• http://riddlelab.msl.ubc.ca/images/maincelegans.jpg• http://images.google.com/imgres?imgurl=http://workforce.cup.edu/
buckelew/images/Trichinella%2520spiralis%2520male.jpg&imgrefurl=http://workforce.cup.edu/buckelew/Trichinella%2520spiralis%2520male.htm&usg=__-N5OebYUengR9rzBklrnegm5b0Q=&h=512&w=640&sz=27&hl=en&start=1&um=1&itbs=1&tbnid=To3n2v9H1z6ALM:&tbnh=110&tbnw=137&prev=/images%3Fq%3DTrichinella%2Bspiralis%26um%3D1%26hl%3Den%26sa%3DG%26ndsp%3D20%26tbs%3Disch:1
• http://www.cals.ncsu.edu/course/zo150/mozley/fall/nematode.jpg
• http://www.nottingham.ac.uk/bennett-lab/nematode.jpg
• http://web.pml.ac.uk/nematode/pictures/images/nematode5.jpg