Unsegmented Worms

PHYLUM NEMATODA ….the roundworms Roundworms

Taxonomy Kingdom: Animalia Phylum: Nematoda Class: Secernentea Adenophorea

Phylum Nematoda Vocab Hookworm * 4. trichinosis 1. parthenogenesis 2. cuticle Hookworm * 4. trichinosis Pinworm* 6. filarial worm* 7. Elephantiasis 8. vermiform 9. cloaca 10. Microfilaria

1. PARTHENOGENESIS- modified form of sexual reproduction by the development of a gamete without fertilization 2. CUTICLE- noncellular, protective organic layer secreted by the external epithelium (hypodermis) of many invertebrates 3. HOOKWORM- (New World or American Hookworm) Necator americanus; found in southern US; adults live in small intestine 4. TRICHINOSIS- caused by (the porkworm) Trichinella spiralis larvae; get from eating undercooked meat; characterized by muscular pain, fever, edema (swelling), & other symptoms 5. PINWORM- Enterobius vermicularis; most common roundworm parasites in the US 6. FILARIAL WORM- Wuchereria spp.; elongate, threadlike nematodes that live in the lymphatic system, where they block the vessels 7. ELEPHANTIASIS- a chronic filarial disease most commonly occurring in the tropics due to the infection of lymphatic vessels with the nematode Wuchereria spp. 8. VERMIFORM- resembling a worm in shape; long and slender 9 . CLOACA- a common opening for excretory, digestive, & reproductive systems 10. MICROFILARIA- the prelarval stage of filarial worms; found in the blood of humans and the tissues of the vector (carrier)

Characteristics Pseudocoelomates- big advancement…. why?

Characteristics cont Most small, many are microscopic, but a few are over 3 feet Bilateral symmetry, cylindrical body tapered at both ends, no segmentation

Characteristics cont No cilia or flagella Mostly dioecious, (male and female reproductive organs in separate organisms of the species) female larger

What system takes up most of the organism’s body?

Characteristics cont Most nematodes are free-living and are found in virtually all habitats, but mostly in soil and fruits. Some are parasitic Plant Nematode

Characteristics cont Have a complete digestive system consisting of a mouth, muscular pharynx, non-muscular intestine (only one cell layer thick), and an anus. 4 parts of a complete digestive system

Quick Review Questions What type of body cavity do nematodes have? What type of symmetry do they have? What does the term “dioecious” mean? Where can you find nematodes? Do they have a digestive system? Explain.

Feeding Many free-living roundworms use grasping mouthparts and spines to catch and eat other small animals.

Respiration, Circulation and Excretion Roundworms exchange gases and excrete metabolic waste through their body walls. They depend on diffusion to carry nutrients and waste through their bodies.

Movement Fluid in the pseudocoelom and muscles extending the length of their bodies function as a hydrostatic skeleton. Aquatic roundworms contract muscles to move like snakes through the water. Soil-dwelling roundworms push their way through the soil by thrashing around.

Reproduction Roundworms reproduce sexually. Most species have separate sexes. Parasitic roundworms often have life cycles that involve two or three different hosts or several organs within a single host.

Questions What do nematodes use their mouthparts for? How do nematodes breathe? How do nematodes move? How do nematodes reproduce?

Discussion 1. Explain why being a pseudocoelomate is a big advancement for nematodes. (Make reference to a previous phylum we have studied and connect the reference to nematodes.) 2. Explain the difference between being a hermaphrodite and being dioecious. Discuss these differences.

Nematode hatching

A Marine Nematode

Parasitic Nematodes Foldable *3 sheets of paper *several markers Wuchereria spp. Parasitic Nematodes Foldable *3 sheets of paper *several markers Ascaris lumbricoides Enterobius vermicularis Necator americanus Trichinella spiralis PARASITIC NEMATODES

Roundworms and Human Disease

Ascaris Ascaris lumbricoides is a serious parasite of humans and many other vertebrate animals. It absorbs digested food from the host’s small intestine.

Ascarids taken from children of one village.

Ascaris Dissection Round Worm Dissection Sexual dimorphism: physical characteristics that are used to differentiate males from females 2 ways to tell males from females: Males are smaller Males have a coiled hook at posterior end for copulation

Dissected Female

Monsters Inside Me…Ascaris

Coughing up worms Ascaris Monsters Inside Me Ascaris

Ascaris lumbricoides Giant intestinal roundworm Ascariasis is the disease you get from the worm Aka Hand to mouth disease Largest roundworm a human can get (up to 16 inches) Begins life as free living eggs in soil 800 million throughout the world are infected Live in small intestine of humans Produce large # of eggs that exit with feces Internal anatomy is mainly reproductive organs & digestive tract 2nd stage larvae is the infective stage Human ingests embryonated eggsthey hatch in the intestinelarvae penetrate intestinal wall & are carried via circulation to lungsmolt 2x in lungsmigrate up trachea & are swallowed

Worms attain sexual maturity in the intestine, mate & begin egg production Infection in US is rare – worm is brought over by people returning from vacation Adult worms can live in intestinal tract for years undetected Can grow up to 16 inches long In undeveloped/unsanitary African countries 95% of the population is infected

Life cycle

Trichinella Adult Trichinella worms live and mate in the intestines of their hosts. Larvae travel through the bloodstream and burrow into organs and tissues. 50 µm Encysted juveniles Muscle tissue

Trichinella cont Trichinella completes its life cycle only when another animal eats muscle tissue containing these cysts. Humans can get trichinosis by eating raw or incompletely cooked pork.

Cysts in Contaminated Pork Trichinella spiralis

Trichinella

Trichinella spiralis Porkworm Live in mucosa of small intestine of humans & other carnivores & omnivores (the pig) In intestine, adult females give birth to young larvae that enter the circulatory system & are carried to skeletal (striated) muscle of same host young larvae encyst in skeletal muscles & remain Another host must ingest infective meat (muscle) to continue the life cycle Humans get it by eating improperly cooked pork Once ingested, larvae excyst in stomach & make their way to the small intestine where they molt 4x & develop into adults

Hookworms Necator americanus..American hookworm Hookworm eggs hatch and develop in the soil. They use sharp toothlike plates and hooks to burrow into the skin and enter the bloodstream.

Hookworms cont Hookworms travel through the blood of their host to the lungs and down to the intestines. There, they suck the host’s blood, causing weakness and poor growth. Small hookworms

Monsters…Flesh-eating Hookworms

Hookworm.. healthbyte http://www.youtube.com/watch?v=IMIDIAUBF8Y Hookworm relationships:) http://www.youtube.com/watch?v=wxGwvE8ytCQ

HOOKWORM *Filariaform=threadlike *this is NOT a filarial worm

Necator americanus New World Hookworm/American Hookworm Found in Southern US Adults live in small intestine where they hold onto the intestinal wall w/teeth & feed on blood and tissue fluid Females can produce 10,000 & eggs daily, which can pass out of the body in feces Egg hatches on warm, moist soil Humans can became infected with a filaria-form larva penetrates the skin & usually between toes Outside defecation & subsequent walking barefoot are methods of becoming infected

Hookworms Mild symptoms: rash, mild diarrhea Severe symptoms: anemia, weight loss Common in areas with warm temp & decent amount of rainfall Tx: 1-3 days of meds to eliminate worms Recheck stool to make sure worms are gone

Filiarial Worms Filarial worms are threadlike worms that live in the blood and lymph vessels of birds and mammals. They are transmitted by mosquitoes. Causes Elephantiasis

Filarial worm in cow eye

Elephantiasis

Elephantiasis cont

Monsters Inside Me .. Filarial worms http://animal.discovery.com/tv-shows/monsters-inside-me/videos/the-40-year-parasite.htm

Filaria- causes, symptoms, etc.

Elephantiasis

Filariasis Treatment.. India

Wuchereria spp. Filarial worms In tropical countries 250+ million humans infected Wuchereria bancrofti & Wuchereria malayi Fluid in connective tissue accumulates in peripheral (outer) tissuesenlargement of various appendages = elephantiasis Transmitted by mosquitoes Prevalent filarial worm in the US is Dirofilaria immitis Since these adult worms live in the heart and large arteries of the lungs, the infection is called heartworm disease Hard to eliminate Condition can be fatal Prevention – heartworm meds

Wuchereria spp. Filariasis – info & treatment Lymphatic system blockage causes excessive swelling 120 million ~ Africa, India, South Asia, Pacifica 25 million Indian people alone Noninvasive treatment 14 days inpatient 1. wash w/ medicated soap 2. submerge in solution 3. antibiotic cream 4. yoga 5. massage 6. wrap in compression Continue treatment at home for 6 months 50% reduction in swelling Strict vegetarian diet

Enterobius vermicularis…PINWORMS http://www.youtube.com/watch?v=6M_bBOSV67Y colonoscopy http://www.youtube.com/watch?v=R0S7nsCVg7E&list=LPI1aJa6N7ACI&index=7&feature=plcp Meducational http://www.youtube.com/watch?v=Zrn7jTqKBFs&feature=BFa&list=LPI1aJa6N7ACI case study

Enterobius vermicularis Human pinworm aka threadworm (UK) Most common roundworm parasite Adults become established in lower part of large intestine @ night, females migrate out to opening of anus & deposit eggs containing 1st stage larva & die Females & eggs produce an itching sensation Easily spread because scratching an itch contaminates the hands & bed clothes/sheets When hands touch mouth & eggs are swallowed, the eggs hatch Larvae molt 4x in the small intestine & migrate to large intestine Adults mate & females soon begin egg production

Small – thin- white – roundworm Can affect all people Common among children, institutionalized persons & household members of persons w/pinworm infection Treatable with OTC (over the counter) or rx (prescription) meds Reinfection, which occurs easily, should be prevented Can do scotch tape test to check for infestation Pinworms are not usually a serious situation

Lifecycle of a Pinworm

NEMATODES & INSECTS

BENEFICIAL NEMATODES?!! Isn’t than an oxy moron? http://www.ladybug.uconn.edu/factsheets/tp_05_nematode.html http://oardc.osu.edu/nematodes/ http://oardc.osu.edu/nematodes/biologyecology.htm

Ascaris Dissection and Nematodes Slideshow http://www.studyblue.com/#file/view/542000

Nematoda Quiz

In roundworms, the body cavity that forms between the endoderm and mesoderm is the ganglion. hydrostatic skeleton. pseudocoelom. coelom.

All of the following are parasitic roundworms EXCEPT Tapeworms filarial worms Hookworms ascarid worms

Characteristics of roundworms include a digestive system with one opening and a pseudocoelom. one opening but no pseudocoelom. two openings and a pseudocoelom. two openings but no pseudocoelom.

Gas exchange and excretion of metabolic wastes in roundworms occurs via a complex system of alveoli. through their body walls by diffusion. through excretory tubules. by flame cells.

The roundworms called ascarids cause harm by causing serious body swelling. burrowing into body tissues and causing pain. causing malnutrition. causing internal bleeding.

In roundworms, the body cavity that forms between the endoderm and mesoderm is the ganglion. hydrostatic skeleton. pseudocoelom. coelom.

All of the following are parasitic roundworms EXCEPT Tapeworms filarial worms Hookworms ascarid worms

Characteristics of roundworms include a digestive system with one opening and a pseudocoelom. one opening but no pseudocoelom. two openings and a pseudocoelom. two openings but no pseudocoelom.

Gas exchange and excretion of metabolic wastes in roundworms occurs via a complex system of alveoli. through their body walls by diffusion. through excretory tubules. by flame cells.

The roundworms called ascarids cause harm by causing serious body swelling. burrowing into body tissues and causing pain. causing malnutrition. causing internal bleeding.