Exam 3 Practice Flashcards: Phylum Nematoda and Protozoa

Comprehensive vocabulary flashcards covering Phylum Nematoda, Trypanosomatidae, Hexamitidae, and Trichomonadidae based on the video transcript and lecture notes.

Pseudocoel

A fluid-filled cavity enclosed by the body wall that functions as a hydrostatic skeleton; it differs from a true coelom because it has no peritoneal (mesodermal) lining.

Cuticle

A noncellular layer secreted by the underlying hypodermis that is shed 4 times (4 molts) during nematode development.

Syncital

The state of the hypodermis in adult nematodes where nuclei lie in four epidermal cords rather than separate cells.

Myocyton

The noncontractile cell body of nematode body wall muscles.

Hemolymph

The name of the fluid found within the pseudocoel of a nematode.

Sensilla

Small sense organs in nematodes that are most prominent in the cephalic and caudal regions.

Depressor ani

Anal dilator muscles that contract to open the anus for defecation driven by hydrostatic pressure.

Trichuris trichiura

Known as the whipworm, this tissue parasite lives $3$ to $5\,cm$ in length and embeds its slender anterior end in the gut mucosa.

Nurse cells

Specialized structures in skeletal muscle fibers where J1 juveniles of Trichinella spiralis reside.

Ascaris lumbricoides J3 stage

The infective stage reached after juveniles molt twice inside the egg; infection occurs when these unhatched juveniles are swallowed.

Autoinfection

In Strongyloides stercoralis, this occurs if juveniles molt twice before exiting the host in feces, allowing them to reinfect the same individual.

Onchocercomas

Benign subcutaneous nodules consisting of collagen fibers surrounding adult Onchocerca volvulus worms; they are located at the site of a black fly bite.

Sclerosing keratitis

A condition resulting from degenerating Onchocerca volvulus juveniles in the eyes, which can lead to blindness.

Dirofilaria immitis

The heartworm, which resides in the right side of the heart and pulmonary arteries of dogs and cats; it is transmitted by mosquitoes.

Elephantiasis

The result of repeated attacks of acute lymphatic inflammation and infiltration of fibrous connective tissue in Wuchereria bancrofti infections.

Loa loa

The 'eye worm' that migrates through subcutaneous connective tissue and shows diurnal periodicity of microfilariae in peripheral blood.

Anisakis simplex

Sometimes called 'sushi parasites,' these marine nematodes require ingestion of raw or undercooked fish and cause extreme gastric pain within $1$ to $12\,hours$.

Retroinfection

A form of reinfection by Enterobius vermicularis where eggs hatch on perianal skin and juveniles migrate back into the anus.

Ground itch

The cutaneous phase of hookworm (Ancylostoma duodenale) infection caused by bacterial infection at the site of invading juveniles.

Heteroxenous

A term describing a parasite that lives within more than 1 host during its life cycle.

Kinetoplast

A dark-staining mass of DNA within a single mitochondrion situated at the base of the flagellum.

Winterbottom’s sign

Swollen lymph nodes at the base of the skull, a characteristic clinical sign of Trypanosoma brucei infection.

Romana’s sign

Swelling and edema of the eye's conjunctiva which occurs when Trypanosoma cruzi enters through that site.

Pseudocyst

A structure formed when Trypanosoma cruzi amastigotes multiply inside cells of the spleen, liver, or cardiac muscles.

Kala-azar

Also known as visceral leishmaniasis, a disease caused by Leishmania donovani that destroys phagocytic cells and causes hepatosplenomegaly.

Promastigote

The stage of Leishmania donovani found in the sand fly midgut and buccal cavity that is injected into vertebrates.

Adhesive disk

A bilobed structure on the ventral surface of Giardia lamblia used to attach to the epithelial surface of the small intestine.

Leukorrhea

A copious white or greenish discharge caused by intense inflammation from certain strains of Trichomonas vaginalis.