LABORATORIO: Parte 2

Filo Nematoda y otros

EJERCICIO 10

Goals for today• Learn to recognized the Phylum Nematoda

and other smaller phyla from other animals• Learn the main ‘diagnostic’ characteristics• Learn about some free-living and parasitic

species biology

Nematoda: roundwormsNematod are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals

Key characteristics of the phylum:•Body elongate and round body.•Unsegmented•Cuticle•Nervous system with pharyngeal nerve ring•Has not circulatory system •Unlike cnidarians or flatworms, roundworms have a digestive system that is like a tube with openings at both ends.•Pseudocoelomate •Widespread and abundant in all habitats; some parasitic

Nematoda: Your TasksExercise 9A:

– Phylum: Nematoda• Genus: Ascaris lumbricoides, A. suum

Ascaris lumbricoides is a common intestinal parasite of humans. A. suum paralyzes pigs. Nearly ¼ of the human population is infected with this roundworm. The eggs are resistant to chemicals, remaining viable in 2% formalin, and 50% solutions of the common laboratory acids

So be careful!! Use gloves and wash your hands after the dissection

Nematoda: Ascaris1. Take a slide from your box with a cross section of a male and female Ascaris.

Nematoda: Ascaris2. Dissection. Use gloves at all times!

Female

Male

Select one sex and then search for a student with the dissection of the opposite sex. Either can be in the exam!

Ascaris lumbricoides cont.Female

vagina

genital pore

uterus

gutoviduct

Ascaris lumbricoides cont.

seminal vesiclesperm duct

testesgut

Male

Male spicules

Nematoda: Your TasksExercise 9A:

– Phylum: Nematoda• Genus: Ancylostoma caninum (dog hookworm)

Observe a slide of the dog hookworm. This is a common parasite of domestic dogs and cats. Try to note the cutting plates which uses to attach itself to the intestinal mucosa of its host.

Read page 161 on hookworms

Nematoda: Your TasksExercise 9A:

– Phylum: Nematoda• Genus: Trichinells spiralis (trichina worm)

Observe a slide of the trichina worm a parasite of humans, hogs, rats and other mammals

Your slide is a cyst of the parasite

Read page 162 on trichina worms

Nematoda: Your TasksExercise 9A:

– Phylum: Nematoda• Genus: Enterobius vermicularis (pinworms)

Observe a slide of a pinworm which parasites humans in USA. They live in the large intestine and cecum.

Read page 162-163 on pinworms

Rotifera: Your TasksExercise 9A:

– Phylum: Rotifera

Observe a slide of a rotifer: Rotifers have a corona of cilia that is use for swimming and feeding. The foot has a pedal gland that secrets a cement to cling on substrate. The mastax is fitted with jaws for grinding food particles. The body is cover by a cuticle which in many roftifers is rigid and called lorica.

There are pseudocoelomates

Habitan en aguas dulces, tierra húmeda, musgos, líquenes, hongos, e incluso agua salada

Acanthocephala: Your TasksExercise 9A:

– Phylum: Acanthocephala

Observe a slide of a spiny-headed worm. This worm is a parasite of pigs, where it attaches to the intestinal lining and absorbs digested food from its host. Like tapeworms it has not digestive system at all.

probóscide invaginable erizada de espinas

There are pseudocoelomates

Important LinksNematods and others

http://faculty.evansville.edu/de3/b10802/PPoint/Pseudocoelomates/sld001.htm

http://www.savalli.us/BIO385/Diversity/13.Nematoda.html

http://en.wikipedia.org/wiki/Nematode

http://en.wikipedia.org/wiki/Rotifer

http://en.wikipedia.org/wiki/Acanthocephala